Solid state preamp grain compared to valves

[Lawrence001]

I've tried a few SS active pres and I haven't been able to get on with them, ultimately I find the sound irritating. I've put this down to a slight silicon grain even on good ones (eg. Audio Research). I've also matched them with a few modern SS power amps that seem to smooth out the grain but they make the sound dull and lifeless. I've never had this with valve pre amps (sometimes harshness with cheaper ones or cheap valves, but never the "grain"). Nor with good passives.

Is it in my head, are my ears/brain sensitive, or is this just the way it is?

Sent from my BLN-L21 using Tapatalk

[Ali Tait]

You like what you like, end of really. What I’ve found is that any active pre isn’t really transparent, they all add a little something to the sound. The Slagle AVC I had was better to my ears than any active pre I’ve tried in my system previously, however I’ve sold that as I got hold of a set of Tribute AVC’s which Anthony of BTE Desgns is putting in a nice box for me. I’m hoping these will be even better.

[Bigman80]

You like what you like, end of really. What I’ve found is that any active pre isn’t really transparent, they all add a little something to the sound. The Slagle AVC I had was better to my ears than any active pre I’ve tried in my system previously, however I’ve sold that as I got hold of a set of Tribute AVC’s which Anthony of BTE Desgns is putting in a nice box for me. I’m hoping these will be even better.The Slagle has an undeniable fluidity. It's a fantastic pre.

I have the DCB1 preamp now and have a better bass control at the expense at a very very slight loss of that beautiful fluidity. It's as good at the soundstaging and to be honest, it's got a slightly better resolution but it really is nip and tuck.

As for grain, Not to my ears and I've just swapped to a Monarchy Audio SM-70 and DCB1. Both solid state. It definitely has more bite and grit but I really like that. Like Ali said, it's whatever you like.

[anthonyTD]

Wide bandwidth, and the ability to be able to drive [properly] the cables, and the front end of what ever power amp your using' these are two very important aspects of a good preamp!
A...

[Marco]

I fully agree, which is where some passives can fall down.

Marco.

[Marco]

I've tried a few SS active pres and I haven't been able to get on with them, ultimately I find the sound irritating. I've put this down to a slight silicon grain even on good ones (eg. Audio Research). I've also matched them with a few modern SS power amps that seem to smooth out the grain but they make the sound dull and lifeless. I've never had this with valve pre amps (sometimes harshness with cheaper ones or cheap valves, but never the "grain"). Nor with good passives.

Is it in my head, are my ears/brain sensitive, or is this just the way it is?


I know where you're coming from Lawrence, as I've experienced the same. However, not all SS preamps are like that; it simply depends on how they've been designed, and crucially, how they 'gel' with the partnering power amp.

Therefore, the effect you're hearing is often more likely to come from a pre/power amp mismatch (and sometimes the cables used), than any defined sonic signature of silicon.

That's why, in my experience, pre and power amps (valve or SS) should always be viewed as a pairing, and therefore considering their respective electrical requirements (and sonic signatures, so that synergy is achieved), is vitally important to get a good sound.

Too many folks, when buying hi-fi equipment, don't build SYSTEMS; they simply assemble a disparate collection of boxes, and somehow expect them to make music. Unfortunately, that's not how it works!;)

Marco.

[Macca]

Most pre-amps are rubbish whether they are valve or solid state.

Best valve pre-amp I have heard is Marco's heavily modded Croft. In fact that is pretty much a custom build really.

Best solid state is Barry's Mark Levinson. I'd have one if I could find one and afford it.

If you can't afford to spend thousands on an active pre-amp get a quality passive and use a compatible power amp.

[Marco]

Yes, that's pretty sound advice. A lot of potentially good systems are hampered by a poorly matched and/or designed preamp.

However (and I know this is not what you're saying, but it's often stated as the case), it's also a fallacy that simply sticking a passive preamp into a system will cure 'all the ills' of an active design.

That simply isn't the case, as is the notion that passives are automatically more 'accurate'. They're not accurate if they're mangling the music signal, because they're being used in the wrong system or with the wrong power amp. You have to get it right.

And yes, the VERY best active designs, valve or SS, don't come cheap. The same applies to phonostages.

Marco.

[Yomanze]

Some of that “grain” could be in the recording itself, where some of the more euphonic valve pres would gloss over it.

Know what you mean about solid state grain though, it’s rare to find solid state gear without it when comparing to valves, just as it’s rare to find solid state precision and tautness with valves.

[Macca]

Some of that “grain” could be in the recording itself, where some of the more euphonic valve pres would gloss over it.

.

Agree but we shouldn't confuse 'grain' in the recording with distortion added by the system. A lot of what people think is 'On the recording' really isn't.

[Marco]

IME, only poor SS preamps sound grainy. The good ones don't, *but*, to my ears, are a little musically bland/matter-of-fact, compared with the best valve designs.

Marco.

[Bigman80]

Some of that “grain” could be in the recording itself, where some of the more euphonic valve pres would gloss over it.

Know what you mean about solid state grain though, it’s rare to find solid state gear without it when comparing to valves, just as it’s rare to find solid state precision and tautness with valves.+1

[hifinutt]

had lots of valve pre amps in recent years , also had quite a few ss and using a bel canto pre 3 ss pre now . i am not sure i would recognise grain and not sure what it is really . it sounds very natural and enjoyable into my class A power amp . i am extremely impressed with it in many ways . amazing vfm but you do need a separate psu to run it

[George47]

Preamps have become the real plain Jane of the audio world.

Many people are recommending that the variable outputs of DACs give a stunning sound, so why bother spending more than fourpence on a preamp?

Of course, the answer is if you do not want to mess up the music then you will need a good preamp. A lot of DACs alter the volume by slicing bits off the signal. So having gone to the expense of getting a brilliant 16 bit (or 24 bit) signal you let the DAC chop off bits and reduce resolution. For me, most passives seem to give a very neutral, detailed sound but some of the drive and impact is lost, sometimes with a loss of brilliance in the high frequencies. And yes even when care is taken to get the impedances right. TVCs seem to be a better match but then there are small badly made transformers and ones where great care is taken to design and make a great transformer. MFA and Townshend seem to get it right.

An awful lot of SS preamps have a (slightly) grainy sound, which can be made worse by intense, compressed music. There are some that do not have that edge (slight?) but they tend to be one-offs or expensive. But a lot of SS preamps sort of make up for it with a very tight and dynamic sound with great bass control.

Getting a valve preamp to give a grainless sound is more straightforward but the less good ones do it by flattening the dynamics. However, when the better ones get it right it can be magical. The sound becomes realisitic and musicians sound like they are trying to communicate something to you not a disembodied voice that is as clear as anything but they could be singing the Reading phone book with more emotion.

You clearly do not like the SS edge and I have to admit I do not either

[Macca]

I wonder how many of us would not be able to distinguish between good valve, solid state and passive pre-amps if we did not know which we were listening to?


Could you go into a strange room with an unknown and hidden system, have a listen and then say - 'That's solid state amplification', or 'that's valve amplification?'


Not tried that myself but I'm pretty sure it would be harder than we think it would.

[Marco]

Preamps have become the real plain Jane of the audio world.

Many people are recommending that the variable outputs of DACs give a stunning sound, so why bother spending more than fourpence on a preamp?

Of course, the answer is if you do not want to mess up the music then you will need a good preamp. A lot of DACs alter the volume by slicing bits off the signal. So having gone to the expense of getting a brilliant 16 bit (or 24 bit) signal you let the DAC chop off bits and reduce resolution. For me, most passives seem to give a very neutral, detailed sound but some of the drive and impact is lost, sometimes with a loss of brilliance in the high frequencies. And yes even when care is taken to get the impedances right. TVCs seem to be a better match but then there are small badly made transformers and ones where great care is taken to design and make a great transformer. MFA and Townshend seem to get it right.

An awful lot of SS preamps have a (slightly) grainy sound, which can be made worse by intense, compressed music. There are some that do not have that edge (slight?) but they tend to be one-offs or expensive. But a lot of SS preamps sort of make up for it with a very tight and dynamic sound with great bass control.

Getting a valve preamp to give a grainless sound is more straightforward but the less good ones do it by flattening the dynamics. However, when the better ones get it right it can be magical. The sound becomes realisitic and musicians sound like they are trying to communicate something to you not a disembodied voice that is as clear as anything but they could be singing the Reading phone book with more emotion.

You clearly do not like the SS edge and I have to admit I do not either

Pretty much my experience too, George. There's no 'perfect preamp', the same as there's no perfect anything else in hi-fi. All have their respective sonic signatures.

Marco.

[Yomanze]

Pretty much my experience too, George. There's no 'perfect preamp', the same as there's no perfect anything else in hi-fi. All have their respective sonic signatures.

Marco.

Yes, I would love to have one of those ‘transparent’ components that objectivists love, because to me, they do not exist! If they did, I would absolutely own one.

[Marco]

I wonder how many of us would not be able to distinguish between good valve, solid state and passive pre-amps if we did not know which we were listening to?


Could you go into a strange room with an unknown and hidden system, have a listen and then say - 'That's solid state amplification', or 'that's valve amplification?'


Not tried that myself but I'm pretty sure it would be harder than we think it would.

I don't think that would work, simply because you'd be completely unfamiliar with the sound of the amps concerned (there is no 'universal sonic signature' for SS and valve amplification), and so have no basis on which to make a judgement.

The thing to do, would be first to familiarise yourself with the sound of the amps (and test system) in question, then attempt to blindly identify which amp was being used at any given time. That way you'd get a proper handle on the differences between both.

In my experience, when you get to the pinnacle of what both SS and valve preamps can do, there's little to choose between the best examples of each.

Marco.

[Marco]

Yes, I would love to have one of those ‘transparent’ components that objectivists love, because to me, they do not exist! If they did, I would absolutely own one.

Me too, as it'd solve a lot of headaches! Plus, it would focus you more on what matters most (listening to music), not fretting over boxes:)

Marco.

[Macca]

I don't think that would work, simply because you'd be completely unfamiliar with the sound of the amps concerned (there is no 'universal sonic signature' for SS and valve amplification), and so have no basis on which to make a judgement.

The thing to do, would be first to familiarise yourself with the sound of the amps (and test system) in question, then attempt to blindly identify which amp was being used at any given time. That way you'd get a proper handle on the differences between both.

In my experience, when you get to the pinnacle of what both SS and valve preamps can do, there's little to choose between the best examples of each.

Marco.

Exactly. I was responding to the various generalisations that were being made about valve and solid state.

I suppose if you had a poor valve amp and a poor solid state amp then you could tell the difference because they would doing different things badly. But once you move into the real quality stuff, forget it. I've seem people mistake solid state amps for valve amps a few times. One of them was an EE who had designed and built many valve and solid state amplifiers.

[Marco]

I suppose if you had a poor valve amp and a poor solid state amp then you could tell the difference because they would doing different things badly. But once you move into the real quality stuff, forget it.

That's pretty much it in a nutshell:)

Marco.

[Haselsh1]

One of the best preamps I have ever owned was by World Audio Design and was their KLP1. I guess in reality it was a passive design that used its 6922 valves simply for driving the interconnects. Its sound was just so fluid and clear with that classic liquid purity. Bloody lovely gadget.

[hifinutt]

that grandinote proemio SS pre that is in BD audio closing sale is pretty good , shame no distributor for the brand now . heaven knows where it summons the bass from , had it in my system for a few weeks while my valve pre was off for repair

[User211]

Quite a few valve preamps display fluidity only when they have been on for a good long time.

Some can get annoyingly overly fluid when they've been on for, say, 4 hours plus.

Their character most definitely changes as the hours go by...

[YNWaN]

When I changed all the internal cards in my pre-amp for those by Ryan Sound Labs (though the make isn’t relevant as such) the reduction in grain was the single biggest improvement - in fact it quite transformed the sound.

[chris@panteg]

I really liked the Concordant range of valve preamps, used an Excelsior for 15 years, marvellous pre.

[anubisgrau]

a number of DIY efforts based of JFETs will bring you closer to natural, grainless sound. it doesn't have to cost a lot. even the original audio note had such designs (there is a version of M7).

[Haselsh1]

Quite a few valve preamps display fluidity only when they have been on for a good long time.

Some can get annoyingly overly fluid when they've been on for, say, 4 hours plus.

Their character most definitely changes as the hours go by...

Time is definitely a factor in my current pre/power setup. This combo doesn't really sound at its best until after maybe an hour or so and it definitely sounds best in ultralinear mode.

[Jimbo]

Quite a few valve preamps display fluidity only when they have been on for a good long time.

Some can get annoyingly overly fluid when they've been on for, say, 4 hours plus.

Their character most definitely changes as the hours go by...

I agree, mine sounds better the longer it's left on and it is usually at its best just before I switch it off and go to bed. But I must factor in the noise floor which is also very apparent in my system especially late at night.

When the two meet, low noise floor and valve optimal operating temperature, I drift on the wavy acoustic dreamland of audio nirvana. :)

I really should stop drinking that stuff!:lol:

[hifinutt]

for any newbies , a definition of what grain is would be good

[Haselsh1]

for any newbies , a definition of what grain is would be good

Well for me, grain is a slight coarseness in the upper mid/treble that sounds like fine sand paper being rubbed together instead of sounding liquid like pure water.

[struth]

For me it's second class whisky [emoji23]

[Haselsh1]

For me it's second class whisky [emoji23]

LOL... so true, so true

[struth]

Lol so the answer is A Bit Rough Around The Edges

[Lawrence001]

Well for me, grain is a slight coarseness in the upper mid/treble that sounds like fine sand paper being rubbed together instead of sounding liquid like pure water.Thanks everyone for their comments, yes this is how I would describe it, but it's more subtle than the description makes it sound. I've had some cheap valve pres that sound good to my ears so I wouldn't base it purely on price or "quality". I'm now using my Django TVC which sounds just right to me.

I have another question. Has anyone encountered an issue where having good full range speakers that work well in the room seem to be bass light when you've been used to ones that have overpowered the room a bit? They hit all the right notes but not as strongly as you're used to in the bottom registers.

Sent from my BLN-L21 using Tapatalk

[hifinutt]

Well for me, grain is a slight coarseness in the upper mid/treble that sounds like fine sand paper being rubbed together instead of sounding liquid like pure water.

brilliant , thats great

[2fastgt4]

Most older people above 40 have this grain already. Because of hearing damage in that very place[emoji56].
Some preamps is softer in the that very spot. But not necessary better.
A transparent pre-amp could sound grainy to some. And harsh to other.

To make a really good transparent ss pre-amp is very expensive. I have one. The price is near 10k $. This is direct from the designer him self. The pre-amp is a dual mono fully balanced no feedback class A design with separate psu.https://uploads.tapatalk-cdn.com/20180721/e9a9248a501067284baa68837ba0e4a9.jpghttps://uploads.tapatalk-cdn.com/20180721/d2c309bf41e0e425b13fed839caed509.jpg

Tommy

[Marco]

Awesome looking pre, Tommy. Must sound great!:)

Marco.

[2fastgt4]

Thanks Marco. It sounds really great to with my Focal Alto Utopia. No grain there.
Awesome looking pre, Tommy. Must sound great!:)

Marco.

Tommy

[Marco]

Wow - nice speakers, too! :respect:

Marco.

[Haselsh1]

Most older people above 40 have this grain already. Because of hearing damage in that very place

I take it you can prove this..?

[Haselsh1]

Andrew (Rothwell), apologies for me making assumptions about such things. When I had the preamp built by WAD themselves I was under the impression that it only used the 6922's to drive the interconnects. I have never tried to cover up the fact that I know jack shit about electronics and that is why I would never attempt to build my own amplifiers. There are things that should be left alone and for me, electronics and valves are two connected things that I will not mess with. I am in no immediate hurry to die due to a huge overdose of electrical shock. I seriously admire those people who grasp such things with fluency.

[2fastgt4]

Prove that older people have hearing lost compared to normal hearing?
Depending on how you understand my meaning of "most" it should be possible.
But ok, maybe I should say a "lot"instead.
And maybe change "damage" to "hearing lost" .
But yes. There is a lot of older people above the fourties starting to have some kind of hearing lost.
When you start to have hearing problems above 10.000hz . Sounds in the problems frequencies will sound destorded or if you are lucky you will not hear it, depending on your problem.

I'm 46 my self. And have tinitus from time to time.
There is an scale for normal hearing according to age. When my tinitus is bad I score as I would be above 65 years. When I'm fine I score better.
The funny part is that I'm more sensitive now when it comes to destorded sound than when my hearing was ok. ( Or , at least I like to think so)

Sorry for bad English and off topic.

On topic :

The pre-amp pictured above comes with eather a small psu or a big one. The picture is the big one.
There is also an little older version of the pre-amp itself. I have been lucky enough to have all version of it.
To the case. When I started out with the first version with the small psu I felt it was very good. But with a little grain. That psu have only two trafo and no capacitors. (But pre-amp have 20 pieces of 2700uf itself). I was told that it would be better with the big psu. Really I didn't believe that. But you know how it is. I had to try the big one with 4 trafo and 16 pieces of capacitors with 4700uf each. And boy I was wrong. A lot of the grain that I fought was problems with my hearing was lost. This pre-amp is very analytic and reviling. But in the positive meaning. It has an unheard dynamic and attack I always longed for. I was very pleased with it. But then the "designer" made a new print with 25 % shorter signal route. And with better resistor a totally new regulator. This is the one pictured. Even the old one have very good measurements topping the best pre-amp you can get. The new one is even better. The sound feels richer and fuller. And it's more pleasant to listen to. It has more of everything.
So I believe that ss pre-amp can sound as good as valve or better after my own taste.

The discussion about pre-amp vs dac with volume control. My experience is that the volume part of the dac is not that good. Therefore a dedicated pre-amp is better.
But it could maybe depend on your system. If any part of your system are holding back more than the dac then there is no reason to buy a 10k pre-amp.

My dac is the B.M.C dac1. It has also analog inputs and a analog volume control.
I have tried it as a pre-amp. And yes it is pretty good. Doing a good work. It plays a little softer and sounds really nice. Most people would be happy with it. And yes it is (almost) crazy to spend 10k on a pre-amp when the dac does it that good.
But there is a good reason to have it if you can afford it. It has a better soundstage. A lot more detailed bass that hits harder. It sounds faster bigger and more Musical. Vocals sounds more realistic. Acoustic instruments sounds way better. I could go on...
Of course this means a lot to me. But others might not even care. And might say that it is not even worth it. Or that they can do the same with DSP. If someone is interested to know the brand pictured above it is the best brand made in Norway. Musical Innovation.

I take it you can prove this..?

Tommy

[SPS]

That grey sound or grain in some hifi amps is not frequency related... My hearing tails off at around 13khz but it's still easy for me to recognise.

[walpurgis]

That grey sound or grain in some hifi amps is not frequency related... My hearing tails off at around 13khz but it's still easy for me to recognise.

Yes. Same here.

[Barry]

I would have thought 'grain' was the same in the audio sense as it is in photography. A fine grain film is smooth, with no obvious texture. A coarse grain film has a 'sandy' coarseness to it; a surface texture which is not smooth.

I don't see why valve electronics should necessarily be free from grain any more than SS electronics.

[walpurgis]

An older A/B amp in need of a service may be producing audible effects from crossover distortion.

[mikmas]

I would have thought 'grain' was the same in the audio sense as it is in photography. A fine grain film is smooth, with no obvious texture. A coarse grain film has a 'sandy' coarseness to it; a surface texture which is not smooth.

Interesting comparison - wonder if the term migrated from one area to the other. 'Grain' in photography is more literal than in audio though given that it refers to the actual chemical grains which will be more visible in some emulsions than others (and can also be exaggerated through the development process.)

Always loved the iconic image of Omaha Beach by Robert Capa and the fascinating story of how it came to be so grainy ....

Find it confusing in relation to audio because it becomes interchangeable with noise, although I think what is referred to here is something different. Also pertinent that grain in photographs tend to be fairly uniform across all tones of a photo (but obviously more visible in darker greys) - how does that sit with 'grain' uniformity across different audio frequencies?

[Barry]

Interesting comparison - wonder if the term migrated from one area to the other. 'Grain' in photography is more literal than in audio though given that it refers to the actual chemical grains which will be more visible in some emulsions than others (and can also be exaggerated through the development process.)

Always loved the iconic image of Omaha Beach by Robert Capa and the fascinating story of how it came to be so grainy ....

Find it confusing in relation to audio because it becomes interchangeable with noise, although I think what is referred to here is something different. Also pertinent that grain in photographs tend to be fairly uniform across all tones of a photo (but obviously more visible in darker greys) - how does that sit with 'grain' uniformity across different audio frequencies?

I don't know Mike - all I know is I first came across the term 'grain' in reference to audio electronics when reading The Absolute Sound magazine back in the late '80s and early '90s. The term wasn't well defined even then.

A bit off topic: why did Capa's image become so grainy? Did he underexpose the shot and so had to push the development? Whatever, 'grainy' photos can often be very effective. In the day I used to use Kodak Tri-X film (400 ASA) for 'arty' black and white photos. Could never see the point in developing film myself, but did spend many (often fruitless) hours in the darkroom printing up various frames, and messing about 'burning in', 'holding back' and 'dodging' areas of the image.

[mikmas]

A bit off topic: why did Capa's image become so grainy? Did he underexpose the shot and so had to push the development? .

There is a whole mythology built up around the image, mostly around an apparent accident in the lab when a bunch of his films from the day were developed. Some versions say that the assistant used a stop bath that was too hot but the most trustworthy points to the temperature of the drying cabinet being set too high and damaging the emulsion (both are contested either way). Another story has it that the Capa's films (along with those of other photographers from the landing) were entrusted to a General who lost many over the side when boarding; as a result, Life magazine used the few shots that did make it back regardless of quality.

What is apparent from the images that have survived was that light conditions were not ideal for such action shots and Capa would have had to open up the lens to get any kind of usable speed and the resultant combination of softness and motion blur made the grain more apparent than in a well lit exposure with a fast shutter.

(end of digression ;) )

[Lawrence001]

My working assumption behind the difference was that there was something about how silicon transistors or op amps work, possibly down to the molecular level or at least a micro level, that produced a mild but perceptible distortion compared to how valves work, but I know nothing about that to justify the argument. If anyone does know the physical mechanism by which a transistor multiplies a signal I'd be intrigued to know.

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[walpurgis]

http://www.michaelsharris.com/electronics/week3/transistorAmplification.htm

Valves do similar things. Check out triode operation.

[Haselsh1]

I totally agree here that grain when applied to photography is a physical characteristic that can actually be measured and quantified. Also of course it can be controlled by development to a greater or lesser degree. Can audible 'grain' be treated in the same way..? I haven't a clue.

[Haselsh1]

A bit off topic: why did Capa's image become so grainy? Did he underexpose the shot and so had to push the development? Whatever, 'grainy' photos can often be very effective. In the day I used to use Kodak Tri-X film (400 ASA) for 'arty' black and white photos. Could never see the point in developing film myself, but did spend many (often fruitless) hours in the darkroom printing up various frames, and messing about 'burning in', 'holding back' and 'dodging' areas of the image.

Grain can be made to be highly excessive by developing a film at 'normal' temperature and then, after fixing, plunging the film and spool into ice cold water. Strictly speaking this is not grain but reticulation. The effect though is very 'arty'.

[Pharos]

The measured distortion figures on SS compared with valve would tend against valves being better.

[Marco]

The measured distortion figures on SS compared with valve would tend against valves being better.

Lol... Dennis, we know that measurements don't always tell the full story, certainly in terms of what people consider sounds best, which ultimately is all that matters. If they did, we'd all be using the same 'universally proven/most transparent', and therefore 'best' amp, speakers, cables or whatever, and forums such as this would have virtually no purpose!;)

Marco.

[Firebottle]

My working assumption behind the difference was that there was something about how silicon transistors or op amps work, possibly down to the molecular level or at least a micro level, that produced a mild but perceptible distortion compared to how valves work, but I know nothing about that to justify the argument. If anyone does know the physical mechanism by which a transistor multiplies a signal I'd be intrigued to know.

Sent from my BLN-L21 using Tapatalk

I'm sure it is the intermodulation distortion, but have no way to prove it.
Harmonic distortion is tolerable or even euphonious whereas intermod is a cacophonous mixture of all frequencies within the recording.

A low level of this can give a coarseness to the overall sonic image.

[Mr. C]

Not having grain in any solid state pre amplifier I own, can't ever say its been a problem.

Some valve pre's do sound very enticing and with system matching can work very well indeed, as has been mentioned before each person choice is that THEIR choice, affected by any hearing issues?, room speaker interface, bad mains supply and system in-balances can all give different results with different systems etc.

I have a good friend who uses an Audio M10 (with further upgrades by AN) sounds wonderfully musical without question, does it bring something to the party hell yes, it is really and truly accurate, nah! but does that matter if YOU enjoy the sound, of course not.

You can knock up a basic active pre amp in a couple of days, a passive even less, you purchase what is right for YOU and YOUR system

Personally passive pre amps good but no cigar, a decent active pre amp imho is essential for quality playback what ever takes your fancy valve or SS.

Put it bluntly your signal either flows across the top of grid plate of a valve or switches throught the FET (some of which are truly superb these days) op-amps like I've said else where:-

"Certainly would agree with the modern chips quoting ultra low noise floors, slew voltages and large bandwidth, low distortion figures, however it is the implementation that delivers the results.

Correct grounding, dual mono isolated power supplies will all help with stage depth, texture, separation and linearity.

Personally I prefer fully discrete designs, yes more 'real estate' required, however the results can be quite special if more long wind"

The pre amp has always been much maligned, however we see it as a prerequisite.

[Haselsh1]

Sorry, I wasn't having a pop at you, I was having a pop at the folks who propagate misinformation and mislead people like you who don't have the electronics background to challenge it. The idea that the valve is there "only" to drive the interconnects implies that a unity gain buffer is so trivially simple that it must be 100% transparent whereas a non-unity gain amplifier is inevitably flawed. It isn't true.
I just don't like to see people misled like you were by WAD.

Cheers Andrew. So there's no need to release the dove of peace then ;)

[Marco]

Personally passive pre amps good but no cigar, a decent active pre amp imho is essential for quality playback what ever takes your fancy valve or SS.

That's also the conclusion I've come to. Even the best ones I've heard, in fully compatible systems, sound a little 'soft' and lacking in 'drive'/punch, thus despite sounding open and 'sweetly musical', reproduce music in a somewhat lifeless fashion, compared with the best actives, valve or SS.

Passives are a good solution, up to a point, particularly in complimentary budget systems, if finds are tight, but for ultimate high-fidelity sound, no. The exception to that rule, however, to my ears, are LDRs, which don't lack drive in the slightest; indeed the best ones, in the right system, can sound rather beguiling.

Marco.

[Macca]

Cobblers. Any active pre-amp will have higher distortion than a passive therefore by definition it cannot offer higher fidelity than a passive.

What you might prefer is a different story.

[Haselsh1]

Since I have gone from cheap to not so cheap I have noticed a much closer approach for both valve and solid state. I think that my current setup is closer than I thought although I doubt it is completely run in yet. Could I be imagining it..? Of course I could.

[Haselsh1]

Cobblers. Any active pre-amp will have higher distortion than a passive therefore by definition it cannot offer higher fidelity than a passive.

What you might prefer is a different story.

Blue touch paper; stands well back :eyebrows:

[Haselsh1]

My experience of passives is that they just suck the life out of the sound giving a bland, lifeless experience. Is that higher fidelity..?

[Marco]

Cobblers. Any active pre-amp will have higher distortion than a passive therefore by definition it cannot offer higher fidelity than a passive.

What you might prefer is a different story.

Well, we'll have to agree to disagree, as you'd soon find out if you borrowed my Croft, for a week, and put it in your system;)

I don't give a flying fuck about measured "higher distortion". That's a rather shortsighted objectivist's outlook. There's MUCH more about getting a system to play music than fretting over distortion, as you well know whenever you hear what a good turntable can do!:ner:

Marco.

[Marco]

My experience of passives is that they just suck the life out of the sound giving a bland, lifeless experience. Is that higher fidelity..?

Indeed, not. Let's make it clear, though: I'm not saying that all passives suck the life out of the music, because *in the right system* fundamentally they don't, simply that they sound a LITTLE that way ('soft'), in comparison with the best (much more expensive) actives.

That is my position on the matter, based upon considerable experience of using both. It's the reason why I've kept my modded Croft (owned now for 12 years) and no longer entertained passives, which I can assure you, I wouldn't have done otherwise, as I can afford to buy pretty much what I want.

Marco.

[Macca]

Well, we'll have to agree to disagree, as you'd soon find out if you borrowed my Croft, for a week, and put it in your system;)

I don't give a flying fuck about measured "higher distortion". That's a rather shortsighted objectivist's outlook. There's MUCH more about getting a system to play music than fretting over distortion, as you well know whenever you hear what a good turntable can do!:ner:

Marco.

You brought fidelity into the discussion: 'Passives are a good solution, up to a point, particularly in complimentary budget systems, if finds are tight, but for ultimate high-fidelity sound, no.'

Whereas for maximum fidelity a passive cannot be bettered. Like I said, whether you prefer the sound of less fidelity is up to you. But your comment above is inaccurate unless we are changing the definition of 'high fidelity' to mean 'what I prefer.' Subjective site or not I don't think we should do that.

[Marco]

Whereas for maximum fidelity a passive cannot be bettered.


Who says so? And I don't care about measurements, as they don't always tell the full story.

If a passive preamp is used in the wrong system, it will make music sound rather lifeless [experience bears this out], ergo that does not equate to high-fidelity, regardless of what the theory says, of passives being more 'accurate', compared with actives, in isolation, out with of when actually employed in a working hi-fi system, to reproduce MUSIC.

As you know, I also prefer valve power amps to SS varieties, for precisely the same reasons, so does that also mean my choice is based upon "preferring the sound of less fidelity", simply because SS amps measure better in terms of distortion?

You brought distortion into the discussion, not me, which is why I mentioned turntables (and vinyl), which somehow manages to sound remarkably good (often better than digital), despite high levels of distortion!;)

And if we're discussing distortion, then at the very end of the music reproduction chain, you've got a pair of transducers that distort the signal more than anything else further up the chain could possibly do, which makes the notion of wanking over the lowest distortion figures upstream, ultimately rather comical...!!:lol:

Quite simply, in the real (listening) world, theories and measurements are often thrown out of the window.

Therefore, contrary to your assertion, I don't "prefer the sound of less fidelity" [knowing me, as a diehard purist, I'm actually quite shocked you've even came out with that statement], far from it; I prefer the sound I consider to my ears is most lifelike - and in my experience, that's delivered by the best valve-based actives.

Marco.

[Macca]

Who says so? And I don't care about measurements, as they don't always tell the full story.

.

Nothing to discuss then since you can only define fidelity via measurement.

[oldius]

I have given up searching for nuance that makes me sound like a pseudo scientist without the skill to back it up.

I listen, and if a component sounds better then it is better, for me. No amount of measuring can replace personal preference.

I use a range of music to determine my preference. If equipment sounds good with that music then I am going to enjoy it.

[Marco]

Nothing to discuss then since you can only define fidelity via measurement.

Yes, but only *if* you believe that whatever measurement you're taking is telling you ALL that you NEED to know about what it is you're measuring, and thus ultimately what you *specifically* want to know!

I contend that often in audio that's not the case, which is why very little is a 'done deal', and most of us are still on a steep learning curve.

For me, as soon as a passive preamp has to deal with a 'real-life' music signal, as part of a working hi-fi system, where other factors then come into the equation, unless used in the right system, all notions of it automatically [the key word here] delivering greater fidelity, than a quality active, go out of the window.

Marco.

[anthonyTD]

Bun fight! :eek::D
Just kidding, I have read this thread with interest, and from my own experience,where preamps are concerned, from owning, and building both solid state and Valve, when everything that matters within the circuit design is taken into account, it is posible to get both topologies to sound remarkebly similar, when compared within the same system.
As for passives,,, on paper, you can argue that because of their simplicity, they are, and should therefore; be the most accurate, but that's only true up until you marry them with whatever source equipment, and power amp your using, that's when the simplicity of their design, becomes their achilies heel, and thus becomes more or less apparent, depending on the system, dont get me wrong, there are many badly designed active preamps out there that suffer in similar ways, and worse, however; in my opinion, and from many years of experience, a good active versus Any passive, will win hands down in most systems!
A...

[Marco]

As for passives,,, on paper, you can argue that because of their simplicity, they are, and should therefore; be the most accurate, but that's only true up until you marry them with whatever source equipment, and power amp your using...


Exactly what I said, and in a nutshell, the reality. If the question was: 'Do passives, *in theory*, offer greater fidelity than actives?' Then I'd say yes of course (only an idiot would disagree), but NOT ALWAYS, in my experience, in practice.

Theories are simply theories; it's what your OWN lugholes tell you in the end that ultimately matters!:)

Marco.

[Mr. C]

Cobblers. Any active pre-amp will have higher distortion than a passive therefore by definition it cannot offer higher fidelity than a passive.

What you might prefer is a different story.

Martin

All amplifiers have some distortion how low that distortion is down to the individual components, design layout construction methods used.

Happily measure any active pre amplifier for you wish totally unbiased, a lot of the transformer type units 'ring' like a bell @ 4Khz and need a serious amount of damping inside the casework, the hand soldered point to point wiring is also left flapping in the breeze we could go into how that generates its own issues. Again implementation is the key

The LDR versions offer a better all round preservative imho if I had to use one it would be this type of passive.

Every-time I have place a passive pre amplifier in my own system, it takes a backwards step in transparency, natural pace (not artificial naim inspired falseness), stage depth and involvement. I have personally had many passive designs over the years including some ultra exotic Japanese uber constructed wonders which cost kidney transplant amounts, beautifully sweet, delicate, nice layering and fluidity in these area's you would struggle to get close even with valves, yet it was like watching a world class painter at work through a first floor window, not all of the perspective was apparent.

We have a couple of customers with the MFA reference unit, it leaves me cold (that doesn't mean its an appealing unit at all for many people), it fits certain genre's of music very well and in their systems does sound good (Not wow my dangles have had an Epiphany or I would trade the wife for it type moment) This goes back to my earlier post, it is what you like not what peter the bell-end's latest bit of equipment is from hifi-dogs bollox forum :doh:

However I have a broad spectrum of music I listen to and that type just doesn't cut the mustard with everything I listen to.

I would agree with Marco on one point though :wow: (I know hell freezes over twice this year!), passives upto £2K are generally better than most equivalent active pre's, there are always exceptions, though it is a valid point, (like Hypex Ncore modules/Tannoys/insert any forums favorite toy of the moment I would term them cheap speed a lot of bang for buck.)

Some interesting reading regarding passives (https://www.remusic.it/EN/Shootout-Test-Eleven-Passive-Preamps-with-Transformers-8e1d2000)

With regard to measurements on the passives I found this on the highly respected Mod squad passive.

Passive pre measurements Stereophile (https://www.stereophile.com/content/mod-squad-line-drive-passive-preamplifier-measurements)

The channel separation measured on the pre amplifier I use is 0.00025%-0.0005% @ 1khz and 1v even at maximum out (40V I know no one will ever use that level!, oh maybe Marco :eyebrows:) is still 0.093% THD

Before everyone jumps in with because it measure good doesn't mean it sound good totally agreed, however this one does!

Use your ears, in your system that is the only way YOU can decide if it is right for you not Joe blogs forum buddy group.

[Yomanze]

It would be interesting to test the impulse response of the preamp + amp, because if dynamics and slam are sucked out using a passive, it should be measurable down the chain.

[Macca]

It would be interesting to test the impulse response of the preamp + amp, because if dynamics and slam are sucked out using a passive, it should be measurable down the chain.

Of course it should.

Sorry, but whilst people continue to confuse personal preference with fidelity this debate is going nowhere.

[Marco]

Except that's not what's happening, certainly where I'm concerned, or indeed Anthony.

Great post, Tony! I shall comment later:eyebrows:

Marco.

[Haselsh1]

Yep, me too, at this moment in time I can pretty much afford whatever I want but as with most things, everything has its value and chucking large amounts of cash at things never promises the golden egg. My experience with passive pre's began in 1997 and ended around 2013 when I just gave up with the damn things. At the current moment I just do not like how they influence the sound. What I do like is what I currently have and that is why I have them as with others who have what they have. Fortunately in this game there is no right and wrong, there is whatever you want it to be and that goes for all of us. Meat and poison spring to mind and no matter what you spend on your gear doesn't make it better than the other it just makes it different. If solid state is grainy and someone likes it that way then to them, it is correct. Whatever we have we have, no right and no wrong simply different. Wouldn't it just be so good if we could focus on the damn music.

[Haselsh1]

I have given up searching for nuance that makes me sound like a pseudo scientist without the skill to back it up.

I listen, and if a component sounds better then it is better, for me. No amount of measuring can replace personal preference.

I use a range of music to determine my preference. If equipment sounds good with that music then I am going to enjoy it.

Lovely comment ;)

[Marco]

My experience with passive pre's began in 1997 and ended around 2013 when I just gave up with the damn things. At the current moment I just do not like how they influence the sound.

Me neither, mate - and influence the sound [in their own way] they most certainly do! They are not 'transparent' devices, as some wrongly claim.

There is NOTHING I've heard in hi-fi that's truly 'transparent', no amplifier, no CD player, no preamp, no capacitor, no ANYTHING. Everything in line with the signal path, imparts its own sonic signature on the music, to a greater or less degree, passive preamps included.

What Macca (seemingly) fails to grasp, in reference to his comments about fidelity, is that if you don't trust the measurements (i.e. them revealing ALL that needs revealed), which supposedly confirms that passives offer greater fidelity than actives, when used not in isolation, but as part of a working system, reproducing MUSIC, then that argument simply falls down, and so there's only one effective arbiter left: your ears!:)

Marco.

[walpurgis]

there's only one effective arbiter left: your ears!:)

Marco.

As always. Measurements may hint at what something may sound like, but a good listen is the only way in the end.

[Haselsh1]

Marco, I agree entirely. I have come to the conclusion that everything influences everything else to some degree or other. All we really have are our ears and our emotions. We either like the sound or we don't and if we don't, move on.

[Haselsh1]

As always. Measurements may hint at what something may sound like, but a good listen is the only way in the end.

Spot on ;)

[Haselsh1]

Measurements..! I have spent over 33 years working in bloody laboratories and I am sick of sodding measurements. Just what the fuck does 0.00033 (or whatever) have to do with my enjoyment of music..? How the hell did that ever influence how Gary Moore played guitar..? I am just getting old and all of the things that come with it.

[Macca]

Yes, listening is the only way to decide if you like it.

Measuring it is the only way to decide if it is accurate or not.


Just because it sounds wonderful does not mean it is accurate. Just because it sounds rubbish does not mean that it is not accurate.

I agree that you can have compatibility problems between a passive pre and a power amp that go away when you deploy an active pre-amp. That does not mean that the passive is not a more accurate pre-amp. It just means that that particular power amp is not suitable for a passive pre-amp.

[Marco]

As always. Measurements may hint at what something may sound like, but a good listen is the only way in the end.

Yup, it's also the *only* way if you don't consider the results of certain measurements as automatically being conclusive, in terms of ascertaining what kind of preamp offers greater fidelity.

Marco.

[Macca]

Fidelity = truth = accuracy.


High -Fidelity = a high level of accuracy.


If we reduce fidelity to 'it sounds more accurate to me personally' that means fidelity is subjective. How can the truth be subjective?


You recall the flagship Hitachi amplifier that was the first amp to measure perfectly? And the subjective reviews said it sounded a bit bland and boring? Did that mean it wasn't accurate? Nope.

[Marco]

Measuring it is the only way to decide if it is accurate or not.


Yes, Martin, but we're going round and round in circles, as you're failing to grasp the point. The fact is, the above is only true *if* you're accurately measuring what needs to be measured.

In terms of the passive vs. active debate, that's only easily done when you examine both in isolation, i.e. a passive is a much simpler device, containing much fewer components than its active counterpart, therefore, *in theory* it manipulates/distorts the signal less. Fine.

In that simple context, a passive will certainly be perceived as offering greater fidelity. But, as Anthony has said [and which you've completely ignored] things can markedly change (a passive's behaviour) when you partner it with a power amp, perhaps one that's incompatible with allowing it to perform optimally: an electrical mismatch.

This can and DOES happen - and it adversely affects the sound.

Therefore, in that scenario/context, how can measurements tell you accurately which is offering the greatest fidelity: a passive used with a sub-optimal power amp, or an active preamp, which causes no such electrical mismatch with said power amp, but is, theoretically, hampered by a more complicated circuit?

Ultimately, *that* is the measurement which needs done, in terms of determining which offers the greater fidelity (in the real world), so how exactly would you suggest you do it?


I agree that you can have compatibility problems between a passive pre and a power amp that go away when you deploy an active pre-amp. That does not mean that the passive is not a more accurate pre-amp. It just means that that particular power amp is not suitable for a passive pre-amp.

Yes, but it also means that the passive preamp in question can't realistically offer 'greater fidelity', until it's partnered with a suitable power amp! That's my whole point. Therefore, passives can ONLY (arguably) offer greater fidelity than actives, if the operating conditions are right - it is not automatically so:)

Marco.

[Marco]

Fidelity = truth = accuracy.


High -Fidelity = a high level of accuracy.


If we reduce fidelity to 'it sounds more accurate to me personally' that means fidelity is subjective. How can the truth be subjective?


Yes, but that's only occurring in your head, because you're so hung up on measurements. That's not what's happening in reality, and certainly isn't where I'm coming from. See my last post.

Marco.

[Mr. C]

Ok

How many recording studio's use a passive pre amplifier in the recording process?

Would you class a recording studio (a quality one shall we say!) as trying to be as faithful as possible to the original sound that the artist, composer or instrumentalist is producing inside that recording environment? Providing the record company isn't compressing the the life out of it (oh wait; maybe the compression filter we use is not a plug but a passive pre in the way? :D )

Accuracy is being able to recreate what is actually being played with almost zero interference, well not really????

If we used zero compression (assuming the equipment in the mixing booth could cope) right across the board, possible 50 people in the world *may* have the audio reproductive equipment to genuinely play it back as close as humanly possible. Then you would need a very large room to help with this task. Plus significant equipment with large drivers and stunning resolving power.

That said could you cope with or would you wish for true realism? I would suggest not even Marco and the Wrexham wall of sound (now much polished :)) would get out of the kitchen so to speak on this matter.

This is why every single recording that has been produced in the last 35+ years or so does have some form of compression contained with in it, the very best recordings still have around 1.5-2dB worth of compression crap like Coldplay X & Y has around 7-9dB of squashing on it also Oasis whats the story morning glory is had the living urine pressed out of it.

This is why a great many classical recordings you need to wind the wick up to truly appreciate the dynamic contrasts they contain, they are recorded at lower volumes to enable you to sample their glory.

At the recent NWAS, I was chatting to a couple of local chaps who were enjoying the show and ask why certain recordings sounded like listening to naim,............ er sorry a car audio system!

We made a demo disc a few years ago for a well know audio company, it demonstrates the same track compressed and again with minimal compression around 2dB on a drum track.

The chaps thought the compressed version was pretty good until I played the same track (level matched) and they were taken aback, all though it trip out the overload protection on the amp :whistle:

Passive pre amps, if you have the resolution in your system they rapidly become the weak link imho

[Macca]

I did mention that not all power amps are compatible with a passive.

It was your statement that an active pre offers higher fidelity than a passive pre that I was disputing. I agree on a case by case basis that may not always be true. But your statement seemed absolutist.

[Macca]

Ok

How many recording studio's use a passive pre amplifier in the recording process?

Would you class a recording studio (a quality one shall we say!) as trying to be as faithful as possible to the original sound that the artist, composer or instrumentalist is producing inside that recording environment? Providing the record company isn't compressing the the life out of it (oh wait; maybe the compression filter we use is not a plug but a passive pre in the way? :D )

Accuracy is being able to recreate what is actually being played with almost zero interference, we not really????

If we used zero compression (assuming the equipment in the mixing booth could cope) right across the board, possible 50 people in the world *may* have the audio reproductive equipment to genuinely play it back as close as humanly possible. Then you would need a very large room to help with this task.

That said cope you or would you wish for true realism? I would suggest not even Marco and the wall of sound (now much polished :)) would get out of the kitchen so to speak



You are confusing recording with playback, they are entirely different things.

Could we cope with true realism? For me, mostly no. I've heard playback in the studio, it's stunning but would I want to come home at night and relax to that? No, I wouldn't.


On the other hand I have an idea of what a 'good' stereo system sounds like and I've noticed many times that my idea does not exactly conform to the ideas of others who are also into this hobby. Okay, we all know a bad sound when we hear it but once we are beyond that taste in presentation, and expectations, are personal and do seem to differ quite widely.

[Marco]

I did mention that not all power amps are compatible with a passive.

It was your statement that an active pre offers higher fidelity than a passive pre that I was disputing. I agree on a case by case basis that may not always be true. But your statement seemed absolutist.

It's not absolutist, but simply based on my experience to date. Any opinion I form is never written in stone. I'm always willing to learn and alter my opinions if necessary.

Therefore, if I ever hear a passive that's better in my system, or someone else's I know well, I'l gladly acknowledge it! Plus, all this measurements bollocks aside, the ACID test is always done by listening to something in your own system, and using YOUR ears to judge the results.

So, let's just say I brought the Croft down to yours, and we put it into your system, in place of your current passive, which you already know is perfectly suited to either of your power amps (no electrical mismatch), and we use both as the test power amp, with both preamps, and after doing some listening comparisons, you come to the conclusion that the Croft is better.

I'm not saying you would, but just suggesting the scenario... So would that mean you "prefer the sound of less fidelity", or simply that the Croft is intrinsically the better preamp, or that it just suits your system better than your current passive?

Which would it be?:)

Marco.

[Macca]

It's not absolutist, but simply based on my experience to date. Any opinion I form is never written in stone. I'm always willing to learn.

Therefore, if I ever hear a passive that's better in my system, or someone else's I know well, I'l gladly acknowledge it! Plus, all this measurements bollocks aside, the ACID test is always done by listening to something in your own system, and using YOUR ears to judge the results.

So, let's just say I brought my Croft down to yours, and we put it into your system, in place of your current passive, which you already know is perfectly suited to either of your power amps (no electrical mismatch), and we use both as the test power amp, with both preamps, and after doing some listening comparisons, you come to the conclusion that the Croft is better.

I'm not saying you would, but just suggesting the scenario... So would that mean you "prefer the sound of less fidelity", or simply that the Croft is intrinsically the better preamp, or simply suits your system better than your current passive?

Which would it be?:)

Marco.

As I said to Tony I know that I do prefer the sound of 'less fidelity'. So I'd take the pre-amp I liked the sound of the most. Not the one that measured best. I'm not Serge!

[Marco]

So if you prefer the "sound of less fidelity", and the preamp you like the sound of most is what matters, why the fook are you so hung up on measurements? :lol:

Ultimately, you obviously don't trust them as much as your ears!

Marco.

[Macca]

I'm not hung up on measurements but the definition of the term 'high fidelity' is based on them. So if you are going to talk about one design having 'higher fidelity' then you are talking measurements. If you are just saying you prefer the sound of that implementation, that's a whole different matter.

Measurements are irrelevant in that case except to maybe explain why, in psychoacoustic terms, you prefer one over the other. I concede that a lot of people have no interest in that.

[Firebottle]

... and no idea how the measurements actually relate to the sound one hears :scratch:

I've just put my Lenco in a heavier plinth, it has taken the sound to the next level, do you suppose that could be measured, I doubt it.

[Marco]

I'm not hung up on measurements....


Lol - well about three pages of your previous posts suggests rather differently!!:D


So if you are going to talk about one design having 'higher fidelity' then you are talking measurements.


Yes, I fully agree, but *only* if the measurements concerned 100% prove what needs proved. I contend that in the debate between actives and passives, and which offers the 'greater fidelity', in the real world (when used in a test system), no such measurements are conclusive. That's the bit you're failing to acknowledge or consider.

In any case, please stop pretending to be a measurement-obsessed objectivist, when clearly you're not [trust me, that's how you're coming across if that wasn't your intention], as a) it doesn't suit you, and b) clearly doesn't reflect your status as ultimately a subjectivist!:ner:

Marco.

[Marco]

... and no idea how the measurements actually relate to the sound one hears :scratch:

I've just put my Lenco in a heavier plinth, it has taken the sound to the next level, do you suppose that could be measured, I doubt it.

Exactly, some things genuinely exist, but currently we're incapable of accurately measuring. In my view, that applies to any claimed automatic 'greater fidelity' of passives, over actives, when used as part of a working system, reproducing music.

Anyway, not to worry... Has the heavier plinth allowed the Lenco to achieve greater fidelity? If you think so, remember you must be just be imagining it, if the improvement can't be measured;)

No doubt your trousers would make it sound louder, though!:D

Marco.

[Macca]

... and no idea how the measurements actually relate to the sound one hears :scratch:

I've just put my Lenco in a heavier plinth, it has taken the sound to the next level, do you suppose that could be measured, I doubt it.

You could measure the output of the deck with both plinths to see if there was any change. I suppose a bit tricky with vinyl as the variables of the deck are going to change slightly with each play anyway.

[Firebottle]

Ha indeed, but I'm not imagining it.

You must come down and check it out.

[hifinutt]

agreed with that tony totally

[Macca]

Ha indeed, but I'm not imagining it.

You must come down and check it out.

Yes, I must. I can get a few days off coming up next few months? Pm your address Alan and I'll see how easy you are to get to.

[DSJR]

Simple, Lenco's rumble through the stylus in the vertical plane as in the mono days, we only used horizontal stylus movement. a Lenco in stereo isn't always a quiet beast.Fitting one into a massier plinth may well take the noise figures down as stray vibrations may possibly be sunk into the plinth better? Back when the G99 was a current model and when we didn't have substantial bases, Hi Fi Sound magazine tested it and found cutting the mains input voltage knocked several db (audible) off the rumble and noise figures. I don't have the scan of the review group test sadly - they also did the 401, TD124 and Sony TTS3000 which won that little measurement battle.

As for active vs passive preamps, it's up to the amp design really I think. The geriatric amps I use don't like passives at all and are as quiet as a mouse with the matching active preamp. The other amps I have a little to do with still, sound fine with the passive and at all volume settings... Valve vs solid state preamps? Depends on the expertise of the designer IMO... Just my take.

[Bigman80]

How would you know of your amp was suitable to be used with either?

Other than trying it that is.

[DSJR]

Turn the volume up fairly high and listen for HUMMMMM (in my case and this is irrespective of earthing arrangements). With other scenarios, the interconnects should I believe, be as low capacitance and short as reasonably possible (a metre or so seems fine with good cables) to prevent the frequency response being unduly affected. Your mileage may well vary though and while it shouldn't work properly (it doesn't really I'm told) the Krell amp Macca now has could be used successfully with a passive pre where this particular amp is balanced right from the input I gather, one leg needing to be tied to 'earth' if used with standard phono connectors, let alone a passive attenuator as well... So, as said above, I reckon you need to try it for yourself and see how the mysic is affected or not - (I used a variable output source to see what my different preamps did when daisy chained in, so am happy with my compromises). No hard and fast rules though.

[Bigman80]

Turn the volume up fairly high and listen for HUMMMMM (in my case and this is irrespective of earthing arrangements). With other scenarios, the interconnects should I believe, be as low capacitance and short as reasonably possible (a metre or so seems fine with good cables) to prevent the frequency response being unduly affected. Your mileage may well vary though and while it shouldn't work properly (it doesn't really I'm told) the Krell amp Macca now has could be used successfully with a passive pre where this particular amp is balanced right from the input I gather, one leg needing to be tied to 'earth' if used with standard phono connectors, let alone a passive attenuator as well... So, as said above, I reckon you need to try it for yourself and see how the mysic is affected or not - (I used a variable output source to see what my different preamps did when daisy chained in, so am happy with my compromises). No hard and fast rules though.I'll give that a try, Dave. When I tried my DCB1 with the Monoblocks, it was as quiet as a grave yard. I'll try it with the Monarchy and see what happens.

Top stuff mate.

[Marco]

Valve vs solid state preamps? Depends on the expertise of the designer IMO... Just my take.

And mine. The latter is ultimately what matters, not measurements!;)

Marco.

[Marco]

Missed this earlier...


Could we cope with true realism? For me, mostly no. I've heard playback in the studio, it's stunning but would I want to come home at night and relax to that? No, I wouldn't.


Defo, I would. It's *precisely* what I seek from my system, and have striven as much as possible to achieve... In Tony's well-known realism scale, I've always been a '10'!:)

I 'relax', and indeed derive most enjoyment from my system, when to my ears it reproduces music in the most lifelike way possible. I don't want anything deliberately 'smoothed off'.

Therefore, when I want to chill out, I keep the volume low, and simply revel in the realistic tone/texture of voices and instruments, and information retrieval at that volume, and when I want 'true realism', I crank it up, so that I achieve the correct level of dynamic impact to convey that effect (as far as possible). Simples!:cool:

Marco.

[Marco]

The LDR versions offer a better all round preservative imho if I had to use one it would be this type of passive.


Indeed, which is why I'm currently having one built to a high spec. So why do LDRs not lack 'drive' or suck the life out of the music, in the way some other passives do, when used with a sub-optimal power amp? In that respect, LDRs don't seem to care!

That question, btw, is directed at all 'techies' present.


Every-time I have place a passive pre amplifier in my own system, it takes a backwards step in transparency, natural pace (not artificial naim inspired falseness), stage depth and involvement. I have personally had many passive designs over the years including some ultra exotic Japanese uber constructed wonders which cost kidney transplant amounts, beautifully sweet, delicate, nice layering and fluidity in these area's you would struggle to get close even with valves, yet it was like watching a world class painter at work through a first floor window, not all of the perspective was apparent.


Exactly my experience, although only up to silver-wired throughout, Music First levels of passive, nothing much more exotic than that, but they've all sounded as you've described: beautifully sweet and open, detailed to a fault, but compared with the best actives, valve or SS, lack 'urgency'/drive, thus ultimately eroding musical involvement - the often elusive and defining factor that makes recorded music 'come alive'.

And with TVCs, as good as they are, I can always hear the sound of the transformers, a bit like with SUTs in comparison with the best MC head amps. The latter usually always have less of a defined sonic signature.


I would agree with Marco on one point though :wow: (I know hell freezes over twice this year!), passives upto £2K are generally better than most equivalent active pre's, there are always exceptions, though it is a valid point...


Au contraire, mon ami... These days, I think there's far more we agree on, than disagree:)

Yes, I'd rather have a well-designed passive, at any price really, than a budget active preamp, especially SS, as in my experience they make music sound as rough as a badger's arse. Some imported Chinese items, however, can surprise.


The channel separation measured on the pre amplifier I use is 0.00025%-0.0005% @ 1khz and 1v even at maximum out (40V I know no one will ever use that level!, oh maybe Marco :eyebrows:) is still 0.093% THD


Ha - and what exactly are you implying, sir?:D


Use your ears, in your system that is the only way YOU can decide if it is right for you not Joe blogs forum buddy group.

I agree, but I also think forums such as this can sometimes be useful for taking the advice of those whose ears you trust, when you aren't in a position to hear something for yourself. In that respect, if you're a regular contributor/reader, you get to know those who like a similar type of sound.

Marco.

[Pharos]

From Marco;
"Who says so? And I don't care about measurements, as they don't always tell the full story. "

I do care about measurements, and they don't tell the full story, but they may in the future..

To lol at a simple statement of truth which is 100% accurate seems inappropriate to me, it was not meant to be a complete treatise of all causes of poor sound quality, but just a statement of a simple isolated fact.

To be an objectivist is surely not to assume that the stance explains everything in an all encompassing and complete way, it is more a declaration of validation of objective criteria, which necessarily are an incomplete attempt at defining performance.

From my POV it is a dangerous path to allow oneself to be seduced by a sound on it apparent subjective enjoyability.

This is so to me because the psychology of our existence shows that we easily tend to rely on comfort zones to avoid anxiety and cognitive dissonance, in all areas of life; it is a human trait which aids survival by allaying anxiety.

Since my recent changes I have been very aware of how I have previously missed detail, and how now often the art is not now beguiling; the subtle improvement has radically changed the presentation and overall picture

I get the impression that the hot weather is affecting the debate here.

[Svend N]

I've tried a few SS active pres and I haven't been able to get on with them, ultimately I find the sound irritating. I've put this down to a slight silicon grain even on good ones (eg. Audio Research). I've also matched them with a few modern SS power amps that seem to smooth out the grain but they make the sound dull and lifeless. I've never had this with valve pre amps (sometimes harshness with cheaper ones or cheap valves, but never the "grain"). Nor with good passives.

Is it in my head, are my ears/brain sensitive, or is this just the way it is?

Sent from my BLN-L21 using Tapatalk

Lawrence, to your original question, I don't think it's in your head at all. You clearly are sensitive to this, which is a good thing in this hobby, being able to discern subtle differences.

I can tell you that I also experienced this with my preamps, and didn't get this sorted out until I had my main pre (Sony TA-E86B) heavily modded and recapped. The timeline went something like this: Sony was stock, driving a Belles OCM 200 power amp, Teac VRDS-10 cd player (unmodded) as main source; I didn't like the sound of the pre (harsh, grainy, lacking openness) so had it converted to be a passive device; this sounded better at the time, until I upgraded the speakers to a harder-to-drive pair and then modded the Teac (clock board, op amps, etc.); after a time I came to realize that the passive state of the preamp was holding the whole system back; just for a lark I temporarily swapped in a Sugden active pre, and Holy Smokes! the system was alive again; so I had the Sony fully hot-rodded and it now sounds sweet, fluid and grain free, with incredible delicacy and detail.

So, to make a long story short, I believe you can get a solid state preamp, even a mid-level one, to sound fluid and sweet, but it may require some modding to eliminate some of the offending parts and replace them with higher-quality ones. I'm thinking things like capacitors, resistors, op amps, connectors. Let's face it, all components, except cost-no-object ones, are designed with compromises to fit a price point. So, assuming the basic circuit design is sound, there should be room for improvement. For this, the advice and service of a top-notch tech is invaluable. The fellow that I used, Dan Santoni, worked a miracle on my Sony -- totally transformed the sound....unrecognisable from the original, and for very reasonable money. So if you have a solid state preamp that you like the sound of, except for a bit of grain, and it seems to match well with your power amp, perhaps it might be worth a consult with a good tech to see if it can be improved.

As for passive pre's, I would have to agree with some of the others (Marco, Shaun, etc.) that they leave a lot wanting in way of dynamics, pace, drive, fullness. What I gained in way of cleaner sound by converting my Sony to a passive, I lost more by ending up with a lifeless system. This became very apparent once I upgraded other components that really revealed the shortcomings of the pre. I suppose it's possible to have a passive pre that is able to provide the power amp with the input that it needs to really drive the speakers, presuming that the latter are an easy load, but that's not been my experience.

BTW, that Sugden I mentioned sounded wonderful! Very full, dynamic, fluid, punchy. It lacks detail and delicacy next to the Sony, but has a fuller, warmer sound. It's a Sugden C-28 model, in case you're interested. Great preamp!

Good luck!

Hope this helps.

Svend

[Bigman80]

I have spent a couple of hours this evening listening for grain (or the perceived idea of grain, as is my understanding) and couldn't find it. Tried multiple poor recordings to try and throw my DCB1 pre into a whirlwind of SS edge and harshness, but no, it wouldn't have it. Tried the Monoblocks (Valve hybrid) and the Monarchy SM-70 (Class A) and neither of them delivered any grain.

I must be looking for the wrong thing if its in cheap to mid priced SS pre's.

What i did notice was a bit more punch and dynamics that i didn't have with the Slagle AVC, but i didn't have it when the Xiang Sheng DAC (SS) was acting as a pre either.

Seems the DCB1 is actually very fluid and detailed. Glad i put it together!

Could better parts make it even better? I will find out as i am going to get the "HOTROD" version of the board and stick a few "Boutique" parts in.

[Lawrence001]

Lawrence, to your original question, I don't think it's in your head at all. You clearly are sensitive to this, which is a good thing in this hobby, being able to discern subtle differences.

I can tell you that I also experienced this with my preamps, and didn't get this sorted out until I had my main pre (Sony TA-E86B) heavily modded and recapped. The timeline went something like this: Sony was stock, driving a Belles OCM 200 power amp, Teac VRDS-10 cd player (unmodded) as main source; I didn't like the sound of the pre (harsh, grainy, lacking openness) so had it converted to be a passive device; this sounded better at the time, until I upgraded the speakers to a harder-to-drive pair and then modded the Teac (clock board, op amps, etc.); after a time I came to realize that the passive state of the preamp was holding the whole system back; just for a lark I temporarily swapped in a Sugden active pre, and Holy Smokes! the system was alive again; so I had the Sony fully hot-rodded and it now sounds sweet, fluid and grain free, with incredible delicacy and detail.

So, to make a long story short, I believe you can get a solid state preamp, even a mid-level one, to sound fluid and sweet, but it may require some modding to eliminate some of the offending parts and replace them with higher-quality ones. I'm thinking things like capacitors, resistors, op amps, connectors. Let's face it, all components, except cost-no-object ones, are designed with compromises to fit a price point. So, assuming the basic circuit design is sound, there should be room for improvement. For this, the advice and service of a top-notch tech is invaluable. The fellow that I used, Dan Santoni, worked a miracle on my Sony -- totally transformed the sound....unrecognisable from the original, and for very reasonable money. So if you have a solid state preamp that you like the sound of, except for a bit of grain, and it seems to match well with your power amp, perhaps it might be worth a consult with a good tech to see if it can be improved.

As for passive pre's, I would have to agree with some of the others (Marco, Shaun, etc.) that they leave a lot wanting in way of dynamics, pace, drive, fullness. What I gained in way of cleaner sound by converting my Sony to a passive, I lost more by ending up with a lifeless system. This became very apparent once I upgraded other components that really revealed the shortcomings of the pre. I suppose it's possible to have a passive pre that is able to provide the power amp with the input that it needs to really drive the speakers, presuming that the latter are an easy load, but that's not been my experience.

BTW, that Sugden I mentioned sounded wonderful! Very full, dynamic, fluid, punchy. It lacks detail and delicacy next to the Sony, but has a fuller, warmer sound. It's a Sugden C-28 model, in case you're interested. Great preamp!

Good luck!

Hope this helps.

Svend

Thanks for the advice Svend, I do have an active pre I like other than the SS issue, it's a Parasound P3. I'll have a think about your suggestions.

Lawrence

[Lawrence001]

I have spent a couple of hours this evening listening for grain (or the perceived idea of grain, as is my understanding) and couldn't find it. Tried multiple poor recordings to try and throw my DCB1 pre into a whirlwind of SS edge and harshness, but no, it wouldn't have it. Tried the Monoblocks (Valve hybrid) and the Monarchy SM-70 (Class A) and neither of them delivered any grain.

I must be looking for the wrong thing if its in cheap to mid priced SS pre's.

What i did notice was a bit more punch and dynamics that i didn't have with the Slagle AVC, but i didn't have it when the Xiang Sheng DAC (SS) was acting as a pre either.

Seems the DCB1 is actually very fluid and detailed. Glad i put it together!

Could better parts make it even better? I will find out as i am going to get the "HOTROD" version of the board and stick a few "Boutique" parts in.

I most notice it with the best quality recordings as there's nowhere for it to hide.

[Bigman80]

I most notice it with the best quality recordings as there's nowhere for it to hide.Ok, a few recordings of good quality will happen today.

Let's see what happens.

[anthonyTD]

:)
Ok

How many recording studio's use a passive pre amplifier in the recording process?

Would you class a recording studio (a quality one shall we say!) as trying to be as faithful as possible to the original sound that the artist, composer or instrumentalist is producing inside that recording environment? Providing the record company isn't compressing the the life out of it (oh wait; maybe the compression filter we use is not a plug but a passive pre in the way? :D )

Accuracy is being able to recreate what is actually being played with almost zero interference, well not really????

If we used zero compression (assuming the equipment in the mixing booth could cope) right across the board, possible 50 people in the world *may* have the audio reproductive equipment to genuinely play it back as close as humanly possible. Then you would need a very large room to help with this task. Plus significant equipment with large drivers and stunning resolving power.

That said could you cope with or would you wish for true realism? I would suggest not even Marco and the Wrexham wall of sound (now much polished :)) would get out of the kitchen so to speak on this matter.

This is why every single recording that has been produced in the last 35+ years or so does have some form of compression contained with in it, the very best recordings still have around 1.5-2dB worth of compression crap like Coldplay X & Y has around 7-9dB of squashing on it also Oasis whats the story morning glory is had the living urine pressed out of it.

This is why a great many classical recordings you need to wind the wick up to truly appreciate the dynamic contrasts they contain, they are recorded at lower volumes to enable you to sample their glory.

At the recent NWAS, I was chatting to a couple of local chaps who were enjoying the show and ask why certain recordings sounded like listening to naim,............ er sorry a car audio system!

We made a demo disc a few years ago for a well know audio company, it demonstrates the same track compressed and again with minimal compression around 2dB on a drum track.

The chaps thought the compressed version was pretty good until I played the same track (level matched) and they were taken aback, all though it trip out the overload protection on the amp :whistle:

Passive pre amps, if you have the resolution in your system they rapidly become the weak link imho

[Mr. C]

Morning Alan

Just one question those trousers that you wore at NWAS were they filled with vampire poo as well????

Your point about the plinths I have no doubt it has made a difference, though one area you could measure is vibration control, a simple seismometer can easily show any difference between vibration, as to whether this is the absolute cause of your improvement one could not say.

[Ammonite Audio]

Morning Alan

Just one question those trousers that you wore at NWAS were they filled with vampire poo as well????

Your point about the plinths I have no doubt it has made a difference, though one area you could measure is vibration control, a simple seismometer can easily show any difference between vibration, as to whether this is the absolute cause of your improvement one could not say.

Sorry Tony - I can't resist putting on my professional acoustician's 'pedant' hat here. I'm assuming that you mean an accelerometer, rather than seismometer? I doubt that it would be physically possible to attach a seismometer to a turntable, and even then it would not measure much above a couple of Hz!

But, that aside, you're correct here - this is one example where it is possible to measure what actually matters, with the right transducer and measurement system.

[Marco]

Hi Dennis,


From Marco;
"Who says so? And I don't care about measurements, as they don't always tell the full story. "

I do care about measurements, and they don't tell the full story, but they may in the future..

To lol at a simple statement of truth which is 100% accurate seems inappropriate to me, it was not meant to be a complete treatise of all causes of poor sound quality, but just a statement of a simple isolated fact.

To be an objectivist is surely not to assume that the stance explains everything in an all encompassing and complete way, it is more a declaration of validation of objective criteria, which necessarily are an incomplete attempt at defining performance.

From my POV it is a dangerous path to allow oneself to be seduced by a sound on it apparent subjective enjoyability.

This is so to me because the psychology of our existence shows that we easily tend to rely on comfort zones to avoid anxiety and cognitive dissonance, in all areas of life; it is a human trait which aids survival by allaying anxiety.

Since my recent changes I have been very aware of how I have previously missed detail, and how now often the art is not now beguiling; the subtle improvement has radically changed the presentation and overall picture

I get the impression that the hot weather is affecting the debate here.

All fair points. However, I was simply commenting on your earlier statement of:

"The measured distortion figures on SS compared with valve would tend against valves being better."

You've agreed that measurements (currently) don't always tell the full story, so therefore that premise applies to the measured distortion figures you're referring to above, in terms of supposedly 'proving' that SS is 'better'.

'Better', perhaps, if you think that's all that decides how good an amplifier sounds, but when you understand that there's a lot more than that to creating a good amplifier (pre or power), you accept that distortion figures are just another fairly meaningless spec, which in reality tells you very little about how that amplifier reproduces music.

Marco.

[Joe]

I get the impression that the hot weather is affecting the debate here.

I think discussing Brexit would be more interesting than this thread's sort of 'oh yes it is'/'oh no it isn't' exchange.

FWIW I've tried active and passive preamps, valve and SS power amps (various combinations of the two) and I couldn't say, with any degree of certainty, which was 'better', in any sense of the word. 'Different', maybe, but not necessarily in a 'SS = more grain' way.

[Marco]

Hi Andrew,


There's nothing magic about a light dependent resistor nor anything about it that makes it superior to an ordinary metal film resistor. In fact they're inferior as resistors. Obviously, they have the useful property of being light sensitive which can be very useful in some applications.
I'm very confident in saying that in a like-for-like comparison between a metal film resistor based attenuator and an LDR based attenuator, you wouldn't hear any superiority from the LDR. "Like-for-like" means having the resistances the same. It would be an invalid test if one had an impedance of, say, 10k and the other 2 meg.

I don't know the details of what you're having made, but I've seen quite a few instances recently where people have referred to "passive" preamps when they have been no such thing. The Nelson Pass B1 is one example and the WAD KLP1 is another. They're simply active preamps with maximum gain of unity. Is it possible that what you're having built is an active preamp with an LDR volume control?

Thanks for that, and noted. Chris, from LDR, is building the latest version of his Stereo Coffee unit for me, with all the recent upgrades, so I'm looking forward to comparing it with my Croft. You can read about the former here: https://www.stereo.net.au/forums/topic/123765-stereocoffee-ldr-passive-preamp-upgrade-preview/

What I was specifically getting at though, was what makes an LDR, unlike other passives, seemingly not as fussy about which power amp it's partnered with, in terms of ensuring that the sound doesn't lack 'drive' or has the life sucked out of the music.

LDRs don't seem to suffer from that issue, but other passives I've heard do, indlusing metal-film resistor based ones, and I'm curious as to why?:)

Marco.

[Bigman80]

Hi Andrew,



Thanks for that, and noted. Chris, from LDR, is building the latest version of his Stereo Coffee unit for me, with all the recent upgrades, so I'm looking forward to comparing it with my Croft. You can read about the former here: https://www.stereo.net.au/forums/topic/123765-stereocoffee-ldr-passive-preamp-upgrade-preview/

What I was specifically getting at though, was what makes an LDR, unlike other passives, seemingly not as fussy about which power amp it's partnered with, in terms of ensuring that the sound doesn't lack 'drive' or has the life sucked out of the music.

LDRs don't seem to suffer from that issue, but other passives I've heard do, indlusing metal-film resistor based ones, and I'm curious as to why?:)

Marco.I'll be watching this with interest, Marco. It's something which has as many detractors as it does fans.

[Marco]

No worries, mate. There'll be a full write-up, with pics, when it happens!:)

Marco.

[Firebottle]

More life? No, I wouldn't say that, probably because it's too nebulous a description for my liking. However, what I'm left with is even more nebulous: more something, but I'm not sure what. :lol:

That of course is the problem in a nutshell, the spoken word is most inadequate at describing what we hear.
Great that you are hearing more 'something'.

I think it helps if you can bounce terms back and forward between a mate so you get a feel for what you are both experiencing.

[Svend N]

The Stereo Coffee appears to be a totally passive attenuator so I have no explanation as to why it should have "more drive" than a more conventional passive attenuator. I have made plenty of passive preamps and to be honest have never experienced the "lifeless" presentation that has been alluded to in this thread. Maybe that's because I usually partnered them with valve power amps or SS power amps with high input impedances. I also always used short (1 metre) lengths of low capacitance interconnects.
I'm currently using an active preamp (transistor, my own design) which I think has the edge on the passives I've made. More life? No, I wouldn't say that, probably because it's too nebulous a description for my liking. However, what I'm left with is even more nebulous: more something, but I'm not sure what. :lol:

Andrew, I believe you've touched on an important point here, namely careful matching of a passive device with a power amp that will work well with it. This matching of complementary components is, of course, something that is mentioned repeatedly on this forum with respect to all sorts of units, not just passive pre's. But back to passive pre amps, I suspect there is more to this than just the pre-/power-amp matching, but also what's happening upstream with the source components and their output, as well as downstream with the speakers and their demand, have some impact on how well a passive pre will work in a given system. Synergy, in other words.

[Ali Tait]

Martin

All amplifiers have some distortion how low that distortion is down to the individual components, design layout construction methods used.

Happily measure any active pre amplifier for you wish totally unbiased, a lot of the transformer type units 'ring' like a bell @ 4Khz and need a serious amount of damping inside the casework, the hand soldered point to point wiring is also left flapping in the breeze we could go into how that generates its own issues. Again implementation is the key

The LDR versions offer a better all round preservative imho if I had to use one it would be this type of passive.

Every-time I have place a passive pre amplifier in my own system, it takes a backwards step in transparency, natural pace (not artificial naim inspired falseness), stage depth and involvement. I have personally had many passive designs over the years including some ultra exotic Japanese uber constructed wonders which cost kidney transplant amounts, beautifully sweet, delicate, nice layering and fluidity in these area's you would struggle to get close even with valves, yet it was like watching a world class painter at work through a first floor window, not all of the perspective was apparent.

We have a couple of customers with the MFA reference unit, it leaves me cold (that doesn't mean its an appealing unit at all for many people), it fits certain genre's of music very well and in their systems does sound good (Not wow my dangles have had an Epiphany or I would trade the wife for it type moment) This goes back to my earlier post, it is what you like not what peter the bell-end's latest bit of equipment is from hifi-dogs bollox forum :doh:

However I have a broad spectrum of music I listen to and that type just doesn't cut the mustard with everything I listen to.

I would agree with Marco on one point though :wow: (I know hell freezes over twice this year!), passives upto £2K are generally better than most equivalent active pre's, there are always exceptions, though it is a valid point, (like Hypex Ncore modules/Tannoys/insert any forums favorite toy of the moment I would term them cheap speed a lot of bang for buck.)

Some interesting reading regarding passives (https://www.remusic.it/EN/Shootout-Test-Eleven-Passive-Preamps-with-Transformers-8e1d2000)

With regard to measurements on the passives I found this on the highly respected Mod squad passive.

Passive pre measurements Stereophile (https://www.stereophile.com/content/mod-squad-line-drive-passive-preamplifier-measurements)

The channel separation measured on the pre amplifier I use is 0.00025%-0.0005% @ 1khz and 1v even at maximum out (40V I know no one will ever use that level!, oh maybe Marco :eyebrows:) is still 0.093% THD

Before everyone jumps in with because it measure good doesn't mean it sound good totally agreed, however this one does!

Use your ears, in your system that is the only way YOU can decide if it is right for you not Joe blogs forum buddy group.

LDR’s can sound impressive, but they don’t measure too well and are not linear.

[Marco]

Does that matter though, Ali, if they sound "impressive" (read as good)?;)

Valve amps don't measure as well in some areas, as their SS counterparts, but it hasn't stopped you or I (who know what a good sound is) from using them as our preferred choice. As ever, feck measurements, and instead use yer lugs: the classic AoS mantra!

:exactly:

Marco.

[Yomanze]

Hi Andrew,
LDRs don't seem to suffer from that issue, but other passives I've heard do, indlusing metal-film resistor based ones, and I'm curious as to why?:)

Marco.

Switching contacts are one of the biggest compromises in audio. DIP switches too. I wonder if it has to do with increased impedance / decreased conductivity at the switch contacts, something that an active can deal with...

[Marco]

The Stereo Coffee appears to be a totally passive attenuator so I have no explanation as to why it should have "more drive" than a more conventional passive attenuator. I have made plenty of passive preamps and to be honest have never experienced the "lifeless" presentation that has been alluded to in this thread. Maybe that's because I usually partnered them with valve power amps or SS power amps with high input impedances. I also always used short (1 metre) lengths of low capacitance interconnects.


As have I, Andrew. I can assure you that the valve power amp I use, cables and system, are 100% compatible with passive preamps, but that hasn't stopped them sounding as I've described, compared with my active valve preamp.

I agree LDRs don't measure well, but regardless of that, they seem not to suck the life out of the music, worry about longer cable lengths, or be as amplifier-fussy, in an electrical sense, as other passives, and I'm sure that there must be a technical reason for that to back up what my ears are telling me.

Marco.

[Ali Tait]

Does that matter though, if they sound impressive (read as good)?;)

Valve amps don't measure as well in some areas, as their SS counterparts, but it hasn't stopped you or I (who know what a good sound is) from using them as our preferred choice. As ever, feck measurements, and instead use yer lugs: the classic AoS mantra!

:exactly:

Marco.

Yes indeed, however Nick measured some fairly high odd order harmonics-

http://www.audio-talk.co.uk/phpBB3/viewtopic.php?f=9&t=5720&hilit=Ldr

[Marco]

This matching of complementary components is, of course, something that is mentioned repeatedly on this forum with respect to all sorts of units, not just passive pre's. But back to passive pre amps, I suspect there is more to this than just the pre-/power-amp matching, but also what's happening upstream with the source components and their output, as well as downstream with the speakers and their demand, have some impact on how well a passive pre will work in a given system. Synergy, in other words.

That's also my view, based on considerable experience, but in terms of my observations on LDRs, it would be good for someone technically knowledgeable to say, 'Yes, that's true, and this is why'.

Marco.

[Marco]

Ok, fair enough. At the moment then, it'll remain as a very real mystery!

Marco.

[Marco]

Switching contacts are one of the biggest compromises in audio. DIP switches too. I wonder if it has to do with increased impedance / decreased conductivity at the switch contacts, something that an active can deal with...

Good shout, Neil. I guess it's possible. I'll see if I can get Chris, from LDR, to comment.

Marco.

[Haselsh1]

Ok, fair enough. At the moment then, it'll remain as a very real mystery!

Marco.

Yes it sure is and I'm still searching for a clue ;) because a lot of what is going on here is akin to proving ghosts exist. We know damn well that something is going on because a lot of us can hear it but trying to tag it with a label is slightly difficult.

[anthonyTD]

The non linearity that some who have tested LDR's elude to, could be key in explaining why LDR's when used as a passive attenuator' seem to overcome some of the shortfalls experienced by those who have been underwhelmed with conventional "pots in boxes" attenuators, eg; by perhaps working in a similar fasion to the loudness controls found on many older type amplifiers, and preamps.
A...

[Marco]

I think that's a good point, and valid, and could explain what I've been hearing, now that you've outlined the relevance of "non-linearity" to the discussion;)

I'll try and explain as best as I can the problems I've found with some passives, highlighted in particular by the Goldpoint (metal-filmed stepped attenuator) unit I spent considerable time and money modifying, which markedly improved aspects of its sound, but never cured it's lack of 'life', and tendency to sound 'dynamically soft', compared with the Croft.

What used to annoy me was that every time I took the Croft out of my system, and put the Goldpoint in, I'd always have to crank up the volume much more to achieve the same loudness levels, at identical points on their respective volume controls, and it would result in a 'softness'/wooly aspect to the sound, which no amount of increasing the volume on the Goldpoint would cure - all that would happen is I'd end up clipping the power amp, chasing the 'lost dynamics', my ears told me were missing...

So in an attempt to solve that problem, I kept changing the value of the resistors (Z-foils) on the Goldpoint, by fitting new ones of a lower value, in a vain attempt to give the sound the 'boost' it needed, at the lower steps of the volume control, and 'equalise' the loudness levels, as well as trying to give it more 'punch' and 'attack', the same as I got from the Croft.

In that respect, I started off with 50K resistors, and ended up using 10k ones! Still to no avail... All that happened was that the sound became too loud, too quickly, and regardless, that lack of 'life', which was very clearly evident, still persisted, and so in the end the Goldpoint was sold.

I've also tried other, much more expensive stepped attenuator-type passives in my system, with very similar results.

Some managed to level the playing field more, in terms of 'punch' and 'drive', compared with the Croft, but ultimately still exhibited the same 'softness', dynamically, ably highlighted when reproducing things like very well-produced (close-miked) recordings of drum solos, where instead of hearing a crisp 'THWACK', of sticks hitting skin, as one would do in real life, with a passive it'd sound as if someone had covered the drumsticks in cotton wool, so it 'padded out' and softened the visceral impact, which that sound should've had.

Popping the Croft in instead though, completely cured the problem, and restored the required 'life' to the sound, in order to make the drum recording in question sound real/lifelike, so that it would make you blink when the sticks hit the skin. That just didn't happen, to anything like the same degree, with any of the passives I've tried.

Now, when I use an LDR, there are no such issues of 'chasing lost dynamics', or trying to equalise loudness levels, as the sound has all the 'balls', 'guts' and 'drive' of the Croft, but sounds like an LDR, exhibiting the beguiling nature of its style of music-making, not a high-end (extensively modified) valve preamp, which does things a little differently, but equally as valuably. That's why I'd like to have access to both types of presentations, and I'm having a Stereo Coffee LDR built.

I hope my ramblings above make some sense, in terms of what I've tried to describe as the problem I perceive with passives, and even better if someone could explain why. I can assure you it's an effect I can genuinely hear, repeatedly too with all different types of music, and that my system is perfectly suited for showing what a good passive can do, which I acknowledge. For me, it's just not as good as what the best actives do, especially the Croft:)

I just don't like equipment that, to my ears, artificially softens the sound of recordings and reduces dynamic impact, to ANY discernible degree - and so far, LDRs aside, that's precisely what I can hear from passives, *in comparison* with the best active designs.

Marco.

[anthonyTD]

What your describing ie; the issue with conventional passive attenuators is probably very similar to most folk who dont get on with them in their systems, the point you made about the differences acheived by changing the resistor values in the Gold point is key in understanding why its sometimes difficult to get conventional passives to work, its all to do with the way the resistor value, and network interact with the source equipment, cabling, and power amp, with an active preamp that has a relatively low output impedance, the issues associated with the passive attenuator resistor networks is pretty much eliminated.
I think that's a good point, and valid, and could explain what I've been hearing, now that you've outlined the relevance of "non-linearity" to the discussion;)

I'll try and explain as best as I can the problems I've found with some passives, highlighted in particular by the Goldpoint (metal-filmed stepped attenuator) unit I spent considerable time and money modifying, which markedly improved aspects of its sound, but never cured it's lack of 'life', and tendency to sound 'dynamically soft', compared with the Croft.

What used to annoy me was that every time I took the Croft out of my system, and put the Goldpoint in, I'd always have to crank up the volume much more to achieve the same loudness levels, at identical points on their respective volume controls, and it would result in a 'softness'/wooly aspect to the sound, which no amount of increasing the volume on the Goldpoint would cure - all that would happen is I'd end up clipping the power amp, chasing the 'lost dynamics', my ears told me were missing...

So in an attempt to solve that problem, I kept changing the value of the resistors (Z-foils) on the Goldpoint, by fitting new ones of a lower value, in a vain attempt to give the sound the 'boost' it needed, at the lower steps of the volume control, and 'equalise' the loudness levels, as well as trying to give it more 'punch' and 'attack', the same as I got from the Croft.

In that respect, I started off with 50K resistors, and ended up using 10k ones! Still to no avail... All that happened was that the sound became too loud, too quickly, and regardless, that lack of 'life', which was very clearly evident, still persisted, and so in the end the Goldpoint was sold.

I've also tried other, much more expensive stepped attenuator-type passives in my system, with very similar results.

Some managed to level the playing field more, in terms of 'punch' and 'drive', compared with the Croft, but ultimately still exhibited the same 'softness', dynamically, ably highlighted when reproducing things like very well-produced (close-miked) recordings of drum solos, where instead of hearing a crisp 'THWACK', of sticks hitting skin, as one would do in real life, with a passive it'd sound as if someone had covered the drumsticks in cotton wool, so it 'padded out' and softened the visceral dynamics that that sound should've had.

Popping the Croft in instead though, completely cured the problem, and restored the required 'life' to the sound, in order to make the drum recording in question sound real/lifelike, so that it would make you blink when the sticks hit the skin. That just didn't happen, to anything like the same degree, with any of the passives I've tried.

Now, when I use an LDR, there are no such issues of 'chasing lost dynamics', or trying to equalise loudness levels, as the sound has all the 'balls', 'guts' and 'drive' of the Croft, but sounds like an LDR, exhibiting the beguiling nature of its style of music-making, not a high-end (extensively modified) valve preamp, which does things a little differently, but equally as valuably. That's why I'd like to have access to both types of presentations, and I'm having a Stereo Coffee LDR built.

I hope my ramblings above make some sense, in terms of what I've tried to describe as the problem I perceive with passives, and even better if someone could explain why. I can assure you it's an effect I can genuinely hear, repeatedly too with all different types of music, and that my system is perfectly suited for showing what a good passive can do, which I acknowledge. For me, it's just not as good as what the best actives do, especially the Croft:)

Marco.

[Marco]

But don't forget, passives automatically offer 'greater fidelity', because they're measurably more accurate!! [Sorry, Macca]:D;)

However, yes, thanks for that. You've offered a reasonable technical explanation for what I can clearly hear, and that's why I've given up now with conventional passives.

Marco.

[Firebottle]

I have been trying to understand just what causes the difference with passive attenuators, I have heard the effect with a few.
I will put forward this hypothesis, so feel free to discuss.

Frequency response and phase response are inextricably linked, so although we cannot hear very high frequencies we CAN discern small phase differences.
When the frequency response of an amplifier or system is limited there is always a phase shift as the frequency limit is approached.

Now keeping things simple, imagine the output of the passive/active preamp driving the capacitance of the interconnect leads:

With a passive with its associated larger output resistance the hf frequency response is always curtailed, very much in the ultrasonic range (to our ears) in virtually all cases, BUT even though we cannot hear the frequency where the response falls there is always an alteration to the phase response.

With an active preamp with a much lower output resistance there is much more drive to charge/discharge the capacitance of the interconnect leads, so the hf response is affected much less, with the correspondingly smaller effect on the phase response.

So my hypothesis is that the missing bit with the passive approach is phase accuracy.

[anthonyTD]

Martin is not wrong in his explanation of why a simple conventional attenuator'when judged purely on its own merits should be capable of higher accuracy, therefore, higher fidelity, however, that is only relavent until you couple it to the source, and power amp impedances, via some form of cabling, then everything else thats connected to it comes into play.
But don't forget, passives automatically offer 'greater fidelity', because they're measurably more accurate!! [Sorry, Macca]:D;)

However, yes, thanks for that. You've offered a reasonable technical explanation for what I can clearly hear, and that's why I've given up now with conventional passives.

Marco.

[Marco]

Martin is not wrong in his explanation of why a simple conventional attenuator'when judged purely on its own merits should be capable of higher accuracy, therefore, higher fidelity, however, that is only relavent until you couple it to the source, and power amp impedances, via some form of cabling, then everything else thats connected to it comes into play.

But don't forget, passives unquestionably offer 'greater fidelity', because they're measurably more accurate!! [Sorry, Macca]:D;)

However, yes, thanks for that. You've offered a reasonable technical explanation for what I can clearly hear, and that's why I've given up now with conventional passives.

Marco.

Lol - daftee, you've posted your reply by editing it into my last post (#144)!!:doh::D

I didn't write that, you did!

Marco.

[Marco]

Anyway, allow me to reply to the post's correct author, lol:


Martin is not wrong in his explanation of why a simple conventional attenuator'when judged purely on its own merits should be capable of higher accuracy, therefore, higher fidelity, however, that is only relavent until you couple it to the source, and power amp impedances, via some form of cabling, then everything else thats connected to it comes into play.

...potentially adversely affecting fidelity, downstream.

Absolutely, the first part is fine, which I completely agree with. It's the latter bit, in bold, which is an indisputable fact, and which potentially changes the behaviour of the passive in question, thus also (potentially) the level of fidelity downstream, which the system is capable of [and which wouldn't be the case with an active design], he was simply failing to grasp:)

It doesn't matter if a passive is as accurate as a very accurate thing. It's useless on its own, and its behaviour, as discussed, and thus performance, is heavily governed by the stuff it's coupled to, which you've mentioned. So what matters in the end, is what you hear coming out your speakers, by using a passive in your system, not how accurate one is on its own merits.

And if you could measure what was happening there [once it's coupled to a source, etc,] that's the measurement that would ultimately be the most important!

Marco.

[struth]

trying to drop you in the shit :D

[Marco]

Ok, returning now to LDRs, so Anthony, are you saying what I've outlined here:


Now, when I use an LDR, there are no such issues of 'chasing lost dynamics', or trying to equalise loudness levels, as the sound has all the 'balls', 'guts' and 'drive' of the Croft, but sounds like an LDR, exhibiting the beguiling nature of its style of music-making, not a high-end (extensively modified) valve preamp, which does things a little differently, but equally as valuably. That's why I'd like to have access to both types of presentations, and I'm having a Stereo Coffee LDR built.


...is simply due to an LDR essentially acting as a 'loudness control', due to its non-linearity?:)

Marco.

[Marco]

trying to drop you in the shit :D

Aye, these Valley Boys are devious buggers!:eyebrows:

Marco.

[Macca]

Anyway, allow me to reply to the post's correct author, lol:



...potentially adversely affecting fidelity, downstream.

Absolutely, the first part is fine, which I completely agree with. It's the latter bit, in bold, which is an indisputable fact, and which potentially changes the behaviour of the passive in question, thus also (potentially) the level of fidelity downstream, which the system is capable of [and which wouldn't be the case with an active design], he was simply failing to grasp:)

It doesn't matter if a passive is as accurate as a very accurate thing. It's useless on its own, and its behaviour, as discussed, and thus performance, is heavily governed by the stuff it's coupled to, which you've mentioned. So what matters in the end, is what you hear coming out your speakers, by using a passive in your system, not how accurate one is on its own merits.

.
I wasn't failing to grasp anything. You made the unqualified assertion that active pre-amps offer the highest possible fidelity, I pointed out that was not true and that a passive attenuator offered higher fidelity. yes I did not qualify that because I figured that the 'when partnered correctly' bit was self-evident. Clearly not.


Re the 'softness' of the passive pre - I am sort of in agreement here, there can be a hint of softness most evident on rimshots/snare. I have noticed that this can be ameliorated or exaggerated by choice of speaker cable and interconnects. It will also vary depending on the design of the passive. I can get snares to hit me between the eyes with my system, however I prefer a less full-on presentation.

I am not convinced that being hit between the eyes by snares is not actually a colouration. It is hard to tell without talking to the studio engineer. I do suspect that it is not truthful and that it is a hang over from the presentation of the old 'flat earth' systems, IIRC Linn Kans were very good at it due to their massive mid-range hump. Obviously all that is speculative.


The Goldpoint passive you had for a while was IMHO not much cop even after the mods, in the passive pre bake off we had at one of the NEBOs it was comfortably in last place I thought. I don't know what other passive pres you have tried in your system.

[anthonyTD]

Well, if something in the audio replay chain has a non linear action, then somewhere in the audio frequency band, there will be more, or less output at certain frequencies, that could just happen to be right in the most sensitive part of our hearing, or it could be way out at one end, or both, this could indeed account for the reason one would prefer one type of passive attenuator, over another, either way; by its very nature, such an attenuator cannot be classed as high fidelity,even though its affect may be deemed as more pleasing, or more real by the individual listener!
Ok, returning now to LDRs, so Anthony, are you saying what I've outlined here:



...is simply due to an LDR essentially acting as a 'loudness control', due to its non-linearity?:)

Marco.

[anthonyTD]

:eek:

I thought I corrected it???:scratch:
Aye, these Valley Boys are devious buggers!:eyebrows:

Marco.

[anthonyTD]

Thats a good way of looking at it Alan.:)
I have been trying to understand just what causes the difference with passive attenuators, I have heard the effect with a few.
I will put forward this hypothesis, so feel free to discuss.

Frequency response and phase response are inextricably linked, so although we cannot hear very high frequencies we CAN discern small phase differences.
When the frequency response of an amplifier or system is limited there is always a phase shift as the frequency limit is approached.

Now keeping things simple, imagine the output of the passive/active preamp driving the capacitance of the interconnect leads:

With a passive with its associated larger output resistance the hf frequency response is always curtailed, very much in the ultrasonic range (to our ears) in virtually all cases, BUT even though we cannot hear the frequency where the response falls there is always an alteration to the phase response.

With an active preamp with a much lower output resistance there is much more drive to charge/discharge the capacitance of the interconnect leads, so the hf response is affected much less, with the correspondingly smaller effect on the phase response.

So my hypothesis is that the missing bit with the passive approach is phase accuracy.

[Marco]

Well, if something in the audio replay chain has a non linear action, then somewhere in the audio frequency band, there will be more, or less output at certain frequencies, that could just happen to be right in the most sensitive part of our hearing, or it could be way out at one end, or both, this could indeed account for the reason one would prefer one type of passive attenuator, over another, either way; by its very nature, such an attenuator cannot be classed as high fidelity,even though its affect may be deemed as more pleasing, or more real by the individual listener!

Sure, I buy that. The only reason I'm entertaining trying Chris' new LDR circuit is because the previous one showed its musical potential. After I've evaluated it, I may come to the conclusion you've outlined, *but* ultimately ALL that matters to me is what I consider sounds best [read as most lifelike] in my system, not what is deemed as objectively offering the 'greatest fidelity', via measurement.

It's also nice having access to two different types of preamp presentations. Plus, I always like having some form of passive, as back-up, in case valves go down on the Croft, or something, and I'm left with no music. They're also handy to use for fault finding exercises:)

Marco.

[Marco]

:eek:

I thought I corrected it???:scratch:

You have. I was referring to the situation before you did!:D

Marco.

[anthonyTD]

Nothing wrong with that, and for the record, I have played about with diffrent configurations of LDR's since Chris brought our attention to them for use in Audio [I was already well aware of them in Guitar amplification, and their usefulness in certain parts of the circuitry] And I agree to a point, they do bring or should I say' allow a certain sense of musicality that is hard to pin down.
Sure, I buy that. The only reason I'm entertaining trying Chris' new LDR circuit is because the previous one showed its musical potential. After I've evaluated it, I may come to the conclusion you've outlined, *but* ultimately ALL that matters to me is what I consider sounds best [read as most lifelike] in my system, not what is deemed as objectively offering the 'greatest fidelity', via measurement.

Plus, I always like having some form of passive, as back-up, in case valves go down on the Croft, or something, and I'm left with no music. They're also handy to use for fault finding excerices:)

Marco.

[anthonyTD]

Ahh well, you were too quick off the mark there! :ner:
You have. I was referring to the situation before you did!:D

Marco.

[Marco]

I wasn't failing to grasp anything. You made the unqualified assertion that active pre-amps offer the highest possible fidelity, I pointed out that was not true and that a passive attenuator offered higher fidelity. yes I did not qualify that because I figured that the 'when partnered correctly' bit was self-evident. Clearly not.


Well it's always best to spit out *exactly* what you mean, not make presumptions, and you wrote post upon post after that, not making the supposedly "self-evident" any more evident!:D


Re the 'softness' of the passive pre - I am sort of in agreement here, there can be a hint of softness most evident on rimshots/snare. I have noticed that this can be ameliorated or exaggerated by choice of speaker cable and interconnects. It will also vary depending on the design of the passive. I can get snares to hit me between the eyes with my system, however I prefer a less full-on presentation.

I am not convinced that being hit between the eyes by snares is not actually a colouration. It is hard to tell without talking to the studio engineer. I do suspect that it is not truthful and that it is a hang over from the presentation of the old 'flat earth' systems, IIRC Linn Kans were very good at it due to their massive mid-range hump. Obviously all that is speculative.


Fair enough, that's your opinion, based on your experience, and I respect that.

Mine is different (as outlined) and very clearly defines my experience to date with passives. What we should do is have a preamp bake-off at yours, where folks can bring different ones along, active and passive, to use with your Krell (and the 'other' thing;)) and we'll see what happens. I'll bring the Croft.

Are you up for that?:)


The Goldpoint passive you had for a while was IMHO not much cop even after the mods, in the passive pre bake off we had at one of the NEBOs it was comfortably in last place I thought. I don't know what other passive pres you have tried in your system.

As I said to you at the time, it worked much better in my own system than it did at the NEBO in question, which unfortunately you never got to hear.

Marco.

[Macca]

Are you up for that?:)



.

Yes we can do that. Although I am happy to concede beforehand that the Krell is not a perfect match for my passive. I have contemplated buying a quality active pre (Meridian or AVI was what I had narrowed it down to) just to experiment.


Interestingly at the phono stage bake off the other week we used the Firebottle KIN pre-amp rather than a passive and although sound quality from the TT was outstanding, when I hooked up my cd player during the lunchtime break I did not get the level of clarity I am used to at home. There was a bit of grain to the sound exactly as per the o/p. But as I said the TT did not have the grain - regardless of the phono stage in use.


So what's that all about?

[Marco]

I'd imagine just some form of mismatch, mate, between your CDP and the KIN. Did you try it with a passive or standalone active preamp, in the same system?

Marco.

[Macca]

Yes, except for the KIN pre-amp it was my system. And I don't get that grain at home unless I'm using an active pre.

[Firebottle]

But maybe perversely the KIN is valve based?

[Marco]

Yes, except for the KIN pre-amp it was my system. And I don't get that grain at home unless I'm using an active pre.

What it your FULL system, from top to bottom, including speakers and cables? If not, there are too many variables to consider, in order to ascertain what caused the problem. It could even have been the mains at the venue, causing the 'grain'.

Marco.

[Macca]

What it your FULL system, from top to bottom, including speakers and cables? If not, there are too many variables to consider, in order to ascertain what caused the problem. It could even have been the mains at the venue, causing the 'grain'.

Marco.

My power amp, my speakers, my speaker cable. Interconnects were Oliver's own brand I think? And my cd player. So only interconnects and pre-amp were different. There was no grain with the vinyl (that I could hear anyway) so the mains being the problem is unlikely on top of unlikely.


I rarely get to hear digital at the bake offs because everyone is so into vinyl, so my experience of active pre-amps with digital is limited to my own experimentations and a couple of occasions at the meets. But the only times I have heard digital sound 'grainless' with an active pre-amp is with Barry's Mark Levinson job and your Frankenstein Croft.

My theory, which will last until I get a better one, is that a correctly implemented passive pre-amp set up will bring out the strengths of digital in a way that only the best active pre-amps can match.

[Bigman80]

My power amp, my speakers, my speaker cable. Interconnects were Oliver's own brand I think? And my cd player. So only interconnects and pre-amp were different. There was no grain with the vinyl (that I could hear anyway) so the mains being the problem is unlikely on top of unlikely.


I rarely get to hear digital at the bake offs because everyone is so into vinyl, so my experience of active pre-amps with digital is limited to my own experimentations and a couple of occasions at the meets. But the only times I have heard digital sound 'grainless' with an active pre-amp is with Barry's Mark Levinson job and your Frankenstein Croft.

My theory, which will last until I get a better one, is that a correctly implemented passive pre-amp set up will bring out the strengths of digital in a way that only the best active pre-amps can match.Yes, they were the SPOTFIRE throughout.

[Macca]

Yes, they were the SPOTFIRE throughout.

Right I wasn't sure. I just plugged in what was available. So cables were the same for both vinyl and cd.

[Bigman80]

Right I wasn't sure. I just plugged in what was available. So cables were the same for both vinyl and cd.Yes mate, no difference at all. Even the same length.

[Barry]

I'm still wanting to know how this "grain" manifests itself aurally. :scratch:

I know what it looks like in an image, which I would describe as a reduction in the signal to noise ratio. Is that what people are calling preamp grain?

[Macca]

It is without question some form of distortion. In the case of CD with an active pre-amp you are taking a signal, amplifying it and then attenuating it again before passing it to the power amp. That's sub-optimal compared to simply attenuating the signal from the cd player, it seems to me?

[Bigman80]

I'm still wanting to know how this "grain" manifests itself aurally. :scratch:

I know what it looks like in an image, which I would describe as a reduction in the signal to noise ratio. Is that what people are calling preamp grain?Me too, Barry.

I'm presuming grain is heard as a lack of fluidity? A coarseness to the sound, maybe harshness.

Other than that I'm not sure, seems no one is!!

[Macca]

I would say a 'slight coarseness' is about right. Just enough to make it not wonderful. Not enough to spoil it.

[Bigman80]

I would say a 'slight coarseness' is about right. Just enough to make it not wonderful. Not enough to spoil it.Ah, ok. Sweet.

[Lawrence001]

Sure, I buy that. The only reason I'm entertaining trying Chris' new LDR circuit is because the previous one showed its musical potential. After I've evaluated it, I may come to the conclusion you've outlined, *but* ultimately ALL that matters to me is what I consider sounds best [read as most lifelike] in my system, not what is deemed as objectively offering the 'greatest fidelity', via measurement.

It's also nice having access to two different types of preamp presentations. Plus, I always like having some form of passive, as back-up, in case valves go down on the Croft, or something, and I'm left with no music. They're also handy to use for fault finding exercises:)

Marco.
I would say a 'slight coarseness' is about right. Just enough to make it not wonderful. Not enough to spoil it.Sounds about right. With some acoustic/chamber music and the valve pre I could close my eyes and with a little imagination, I'm at the performance. With the SS, it's still being reproduced by a slightly flawed system.

Sent from my BLN-L21 using Tapatalk

[Joe]

I'm still wanting to know how this "grain" manifests itself aurally. :scratch:

It's like an ear of wheat, basically.

[walpurgis]

It's like an ear of wheat, basically.

Or. If you look at a plank of wood you'll get the principle.

[Barry]

Or. If you look at a plank of wood you'll get the principle.

Yes, but what does it sound like?

Is it the same reason why lavatory seats usedto be made from a hard wood (mahogany) for the rich, but any old soft wood for the less well off? (i.e. fewer splinters in the bum)

[Marco]

We've always had hardwood bog seats (our current is ebony, hides any skidders:eyebrows:). Plus it's nice and warm. I wouldn't dream of placing my arse on anything plastic!

That stuff's for oiks.

As for what "grain" on poor SS preamps sounds like. It's simply an edgy/harsh, metallic form of distortion, like a grainy voice on a transistor radio.

Think of a diluted version of that sound (usually right in the presence region of an amplifier's response), superimposed onto the music, which grates on you with repeated listening:)

Good valve amps are blissfully free of it, as it's pretty much a silicon thing (when done badly).

Marco.

[Scooby]

I'm still wanting to know how this "grain" manifests itself aurally. :scratch:

I know what it looks like in an image, which I would describe as a reduction in the signal to noise ratio. Is that what people are calling preamp grain?

https://image.ibb.co/c5qUM8/FAB0_E281_A030_41_E1_ABB6_DBE83_BDE4_A6_F.jpg (https://imgbb.com/)

[Haselsh1]

Yes, but what does it sound like?

Is it the same reason why lavatory seats usedto be made from a hard wood (mahogany) for the rich, but any old soft wood for the less well off? (i.e. fewer splinters in the bum)

Ah, so that's why my Les Paul is made of mahogany - fewer splinters in the bum ;)

[Marco]

Anyway, the point I'm trying to make is that passive volume controls cannot be fundamentally flawed and suck the life out of music because they're at the heart of nearly all active preamps, which don't suck the life out of music (allegedly).

They're not fundamentally flawed, Andrew, as long as what they're coupled to doesn't hobble their effectiveness. If so, then in a revealing system, you'll hear it - simples!:)

Marco.

[Marco]

Best ask Anthony that one, if you're looking for a technical explanation. He touches on it here (impedances seem key to the whole issue):


What your describing ie; the issue with conventional passive attenuators is probably very similar to most folk who dont get on with them in their systems, the point you made about the differences acheived by changing the resistor values in the Gold point is key in understanding why its sometimes difficult to get conventional passives to work, its all to do with the way the resistor value, and network interact with the source equipment, cabling, and power amp, with an active preamp that has a relatively low output impedance, the issues associated with the passive attenuator resistor networks is pretty much eliminated.


Perhaps when he next visits this thread he'll expand more on that?:)

Marco.

[RobbieGong]

I'm no expert as to what the root cause(s) of grain can be whether talking preamps or otherwise.

In the context of systems in general it's something that you hear about and i'm sure people experience it with valve based and SS based systems.

We know that 'dirty / noisy mains' is one of the causes of a grainy presentation and numerous audiophiles have expressed an obvious removal of hash /grain by addressing mains.

BUT, I'm sure there are those who have separate, dedicated, upgraded mains supplies who still experience some kind of the hash / grain we're talking about here :scratch:

I'd say (very simply) Grain, Hash - Potential causes ( Far from exhaustive )

- Noisy / dirty mains
- Distortion - too many causes to go over in depth but include inaccurate stylus / cartridge / tonearm set up, resonances and so on..
- Some cables, interconnects by their makeup alone can cause a level of edginess to the presentation

Some kit componentry will show what I'd call an 'implementation mindset' for low low distortion which has to be a good thing

- The recording. Now this is an area that gets very little consideration in my veiw compared to how much talk goes into everything else hifi related.

Some recordings are not as great as we'd like to believe they are and contain a level of hash/grain/distortion/noise recorded into / with the playback music, absolutely.

The better your system becomes and is at revealing everything from the recording is the more that should become a realisation. Some recording will display none or very little hash / grain, other recordings not so.

I believe a lot of time is spent going round in hifi circles, changing things out due to a lack of realisation / light bulb regards the above. That futile search to have / build a system that plays 'everything' perfectly...... go figure :scratch: :mental: :rolleyes: ;)

[Firebottle]

The capacitance of interconnecting cable is largely eliminated within an active preamp, yet the argument still doesn't seem entirely convincing to me. After all, the capacitance of 1 metre of interconnect could be less than 100pF. Would that be enough to "suck the life out of the music"?

See my post http://theartofsound.net/forum/showthread.php?59315-Solid-state-preamp-grain-compared-to-valves&p=996971#post996971 for a possible explanation.

[hifinutt]

Indeed, not. Let's make it clear, though: I'm not saying that all passives suck the life out of the music, because *in the right system* fundamentally they don't, simply that they sound a LITTLE that way ('soft'), in comparison with the best (much more expensive) actives.

That is my position on the matter, based upon considerable experience of using both. It's the reason why I've kept my modded Croft (owned now for 12 years) and no longer entertained passives, which I can assure you, I wouldn't have done otherwise, as I can afford to buy pretty much what I want.

Marco.

next time i get a MFA baby ref passive , i am going to do a tour and see how much bass and slam and dynamics it brings to a system , its extraordinary [oh and i don`t work for jonathan !!]

[Macca]

. The gain stage could be valves, op-amps, discrete transistors etc. It doesn't really matter for the purpose of this argument.
So with this type of design the active preamp could be seen as a passive preamp plus gain stage. BTW, this is opposite to how Macca thinks the design works, ie gain stage plus passive device, as mentioned here:



So an active pre-amp first attenuates the signal then adds gain? That's the opposite of what I said but that doesn't make any sense?

[Marco]

Yes, but I'm not sure how a phase shift at ultrasonic frequencies would affect dynamics or "suck the life out of music".

I think 'sucking the life out of music' is a tad strong; the best passives, used in a favourable context, certainly don't do that. It could be quite the opposite!

However, in my experience (read what I posted yesterday on the matter), they *can*, when coupled to partnering equipment and/or cables that somehow inhibit their efficacy, soften the sound, so that there is a perceived lack 'punch' and 'guts' with music, compared with a good active design.

Like I said, I can only report what I hear.

For me, conventional 'pots in a box' are best used when they've been designed, from the ground up, to partner a suitable power amp and cables (a single-manufacturer solution), so that synergy is achieved and the whole 'package' works together as intended.

That isn't the case, IME, and harder to get right, when you simply insert (any old) passive into an 'alien' system, which it hasn't been designed to work properly in.

Just my view:)

Marco.

[Marco]

next time i get a MFA baby ref passive , i am going to do a tour and see how much bass and slam and dynamics it brings to a system , its extraordinary [oh and i don`t work for jonathan !!]

Nice one, but that'll only happen if the test system used allows it.

Marco.

[Barry]

In Douglas Self's book Small Signal Audio Design he has two rules:
1) don't attenuate and then amplify.
2) don't amplify and then attenuate.
Ok, he has an odd sense of humour but the point he's trying to make (I think) is that both do harm, either to the signal-to-noise ratio or the distortion.
Anyway, attenuating with a passive volume control and then amplifying is the way most active preamps are designed. Yes, a fully active volume control as part of a feedback network is more sophisticated and technically better but for some reason isn't often used.

I believe one of the first people to put the volume control in the feedback network was Stan Curtis with the Cambridge P60 amplifier.

[Macca]

In Douglas Self's book Small Signal Audio Design he has two rules:
1) don't attenuate and then amplify.
2) don't amplify and then attenuate.
Ok, he has an odd sense of humour but the point he's trying to make (I think) is that both do harm, either to the signal-to-noise ratio or the distortion.
Anyway, attenuating with a passive volume control and then amplifying is the way most active preamps are designed. Yes, a fully active volume control as part of a feedback network is more sophisticated and technically better but for some reason isn't often used.

Thanks, I understand now.

[Bigman80]

next time i get a MFA baby ref passive , i am going to do a tour and see how much bass and slam and dynamics it brings to a system , its extraordinary [oh and i don`t work for jonathan !!]Visit here first Phil, I accept the challenge [emoji4]

[Bigman80]

In my limited experience of preamps,

Passives don't suck the life out, but can at times lack drive.

The Slagle AVC, was something which didn't lack drive but is still a passive device. It worked well on anything I put it with. I always felt it didn't grip the bass as well as the active units though which lead to the change.

SS or Valve based active preamps like the KIN, Croft 25 etc, always felt livelier and more exciting, for whatever reason

The Unity gain DCB1 I have here seems to have that same lively drive as the SS & Valve pre but does the delicate stuff as well as the passive and AVC pres. Is ideal? Probably not and that will show over time.

As far as I can see there isn't a perfect pre except for no pre. I would like to try a good LDR just to see what it does although is suspect it will a similar situation.

[Marco]

The Slagle AVC, was something which didn't lack drive but is still a passive device. It worked well on anything I put it with. I always felt it didn't grip the bass as well as the active units...

Yes, I've also found the same with transformer-based passives, in that they can't quite shake off a slight thick, tubby quality and lack of grip, in the bass. I also find them to be, tonally, on the warm side of neutral. Lovely in other areas, though:)

Marco.

[walpurgis]

Yes, I've also found the same with transformer-based passives, in that they can't quite shake off a slight bloated, tubby quality and lack of grip, in the bass. Lovely in other areas, though:)

Marco.

You wouldn't say that If you heard my MingDa MC-9 Marco. It has none of those issues.

[Marco]

Fair enough, Geoff. Haven't hear it, so can't comment:)

Marco.

[Macca]

You wouldn't say that If you heard my MingDa MC-9 Marco. It has none of those issues.

There's just way too much generalising going on here for it to be any use to anyone.

[Bigman80]

Yes, I've also found the same with transformer-based passives, in that they can't quite shake off a slight thick, tubby quality and lack of grip, in the bass. I also find them to be, tonally, on the warm side of neutral. Lovely in other areas, though:)

Marco.They do make wonderful music but I agree, slightly warmer than neutral. Not a bad thing with some gear though.

[walpurgis]

The Promitheus TVC I use has some of the 'character' Marco mentions, But not the MingDa. They sound very different, so I don't think general characteristics can be attributed to all TVC's.

[karma67]

There's just way too much generalising going on here for it to be any use to anyone.

i agree,im confused to f.... lol
if you want a good listen to grain my advice is buy a lentek head amp :cool:

[Bigman80]

i agree,im confused to f.... lol
if you want a good listen to grain my advice is buy a lentek head amp :cool:Lmfao

Good job there's no in the PE or the sellers would be mad [emoji23][emoji23]

[walpurgis]

i agree,im confused to f.... lol
if you want a good listen to grain my advice is buy a lentek head amp :cool:

Yes. I know people seem to like them, but I thought they sounded rather bland and a bit 'grey'. I had a batch of several NOS items and tried each one.

[Marco]

There's just way too much generalising going on here...

Who from? As far as I can see, we're all speaking from experience. No-one can be expected to hear every different passive preamp of the same type, but we can comment on those we've heard so far:)

Marco.

[Marco]

They do make wonderful music but I agree, slightly warmer than neutral. Not a bad thing with some gear though.

Indeed, but not in a very revealing, wide-open system like mine, where anything with a defined 'signature' is ruthlessly revealed.

Marco.

[Macca]

All transformer pre amps sound tubby, all passives lack drive, valve pre amps don't have any grain, solid state do etc etc.


It's worse than 'What Hi*Fi'. :D

[Marco]

The Promitheus TVC I use has some of the 'character' Marco mentions, But not the MingDa. They sound very different, so I don't think general characteristics can be attributed to all TVC's.

Definitely not. As I said, you can only comment on what you've heard so far. I've heard about four different types of TVC, and they've all shared that character, to a greater or lesser degree, and it's not something I want, or need, in my system.

The MingDa sounds interesting, though:)

Marco.

[Marco]

All transformer pre amps sound tubby, all passives lack drive, valve pre amps don't have any grain, solid state do etc etc.


It's worse than 'What Hi*Fi'. :D

Lol - an interesting précis, which I guess could be garnered by simply skim-reading the thread!

Marco.

[Marco]

if you want a good listen to grain my advice is buy a lentek head amp :cool:

Lol - I'm surprised you say that, as I thought you liked them! The grain is only in stock form (it's a signature of the Tants). That goes away when they've been re-capped, and they do work well with a DL-103:)

Marco.

[karma67]

sorry i should have been more clearer,yes they are not bad sounding until you compare one with a ha-500 then the standard lentek's grain shows itself. :cool:

[Marco]

Agreed:)

Marco.

[AD Audio]

You like what you like, end of really. What I’ve found is that any active pre isn’t really transparent, they all add a little something to the sound. The Slagle AVC I had was better to my ears than any active pre I’ve tried in my system previously, however I’ve sold that as I got hold of a set of Tribute AVC’s which Anthony of BTE Desgns is putting in a nice box for me. I’m hoping these will be even better.

interesting. I think i heard your Slagle AVC which prompted me to buy one butI found it performed even better when used at the front end of my Satchmo preamps instead of a stepped ladder attenuator

[hifinutt]

Visit here first Phil, I accept the challenge [emoji4]

you are on ollie , took a V2 classic to a friend with a big room and big speakers , he was using a vol controlled dac into power amps which were pretty powerful . it was an ok`ish sound but a bit irritating , the person and his musician friend were rather stunned when i put the v2 in . the soundstage widened and the windows began to reverberate . they bought one from a dealer a few days later

[Bigman80]

Well no big room here but ok sized speakers for the room. It will be very interested to see what happens. Top stuff, I'll await the details!!!

[Haselsh1]

The one that sticks in my mind the clearest of all was the Creek passive that I owned around 2004/5. I used it alongside my WAD KLP1 which was far superior in terms of sound with the Creek being very flat and lifeless. All of the dynamic excitement had just gone from the music but unfortunately I cannot remember the power amp I was using.

[Macca]

It's rare that you see anyone who heard that Creek passive saying they liked it. Except Hi-Fi World for a while.

[walpurgis]

The one that sticks in my mind the clearest of all was the Creek passive that I owned around 2004/5. I used it alongside my WAD KLP1 which was far superior in terms of sound with the Creek being very flat and lifeless. All of the dynamic excitement had just gone from the music but unfortunately I cannot remember the power amp I was using.

I tried one very briefly. I found it the same. Grim!

My twenty quid Little Bear passive from China is vastly superior.

[Lawrence001]

Wow my initial question has invoked a long and wide ranging discussion. Given the number of people who find a similar result to me, the conclusion must be that there is some ill effect from most SS pre amps that could be described as grain.

[RobbieGong]

Wow my initial question has invoked a long and wide ranging discussion. Given the number of people who find a similar result to me, the conclusion must be that there is some ill effect from most SS pre amps that could be described as grain.

Yeah 23 pages is one pretty long discussion :)

[walpurgis]

Getting to the point. I don't know what each person may think of as 'grain', but every transistor pre-amp I've tried has had a touch of sheen at the top end (compared to other types). Not necessarily much and not enough generally to detract from the listening experience. I have had the occasional valve pre-amp that did the same, but not many, most are silky smooth (sometimes too much so). My current TVC, passive and valve pre-amps are not guilty of this.

[Clive]

I think when you hear a preamp or phono stage deliver that chrystal clear treble with no hint of courseness you know what grain is with lesser kit.

[alphaGT]

Years ago, while wondering exactly what my preamp sounded like, I decided to bypass it entirely. I plugged my CD player directly into the amp. No volume control, no anything but my best set of cables.

It was loud! But not dangerously so. In fact I listened to it for a few hours in this way. The wife wasn’t real happy when she attempted to turn it down. Upon putting my preamp back into the circuit I found that I much preferred the sound with the pre. A budget solid state Adcom. I couldn’t see where it added anything bad to the sound.

Russell

[anthonyTD]

Its true, many active preamps have the attenuator at the beginning, and thus attenuate the signal before it goes into a gain stage, this usually means that you keep the fixed resistance of the pot across the source, and then vary the input resistance to the input of the gain stage in the preamp, the gain stage of the preamp is then left wide open to drive the power amp. With a passive, its the same configuration, except you have no extra gain after the attenuator, thus, you're relying on how the front end of the amplifier copes with the somewhat low and varying input resistance [depending on how loud you want to listen] presented to the first gain stage of the amplifier, by the attenuator, this is where IMHO the real problem lies with many passive/amp combinations. In my Soul-mate preamp, I eliminated those variant for that very reason, by putting the switched attenuator between two stages, [single ended in this case] each with a very low output impedance buffer circuit, one to drive the attenuator, and one at the end to drive the power amp, that way, the varying attenuator has no affect on the source output resistance/impedance, or the amplifier input, Also' the whole preamp circuit, including the attenuator is directly coupled. I developed this preamp over 14 years ago now, originally specifically to be partnered with the Soul power amps, however, they have been used in many types of systems over the years, with excellent results, my point being, I was well aware of the problems with both good passives, and conventional actives, and I wanted to eliminate as much as possible the issues associated with both types.

[Marco]

Interesting, Anthony, so is the following the reason why results can be so variable with passives, unless they're used with power amps designed to optimise them (and vice versa):


With a passive, its the same configuration, except you have no extra gain after the attenuator, thus, you're relying on how the front end of the amplifier copes with the somewhat low and varying input resistance [depending on how loud you want to listen] presented to the first gain stage of the amplifier, by the attenuator...


...and why, if that arrangement is sub-optimal, it can adversely affect the sound in the way I've described? :)

Marco.

[anthonyTD]

Its all very circuit dependant ie; Attenuator, cables, input resistance, impedance, of the power amp etc.
Interesting, Anthony, so is the following the reason why results can be so variable with passives, unless they're used with power amps designed to optimise them (and vice versa):



...and why, if that arrangement is sub-optimal, it can adversely affect the sound in the way I've described? :)

Marco.

[Marco]

Its all very circuit dependant ie; Attenuator, cables, input resistance, impedance, of the power amp etc.

Yup, but basically it's the reason why it's not a given that any old passive preamp will work well in any old system. There has to be some thought put into it:)

So what I highlighted of yours in my last post, active preamps don't suffer from? I know that they have their own issues, though.

Marco.

[Stratmangler]

This article explains a lot about the input/output impedance thing in plain English https://www.lifewire.com/output-impedance-3134904

[mikmas]

This article explains a lot about the input/output impedance thing in plain English https://www.lifewire.com/output-impedance-3134904

That was indeed a very helpful article ... and easier to follow than many.

I found this paragraph very interesting but am curious what exactly the 'substantial effect on the frequency response' would be (i.e. how it would sound) Don't know if any tube amp designers would care to clarify/comment.

"to simulate the sound of a tube amp in his Sunfire solid-state (transistor) amplifiers, famed designer Bob Carver added a “current mode” switch that placed a 1-ohm resistor in series with the output devices. Of course, this violated the 1-to-10 minimum ratio of output impedance to expected input impedance that we discussed above, and thus had a substantial effect on the frequency response of the connected speaker, but that’s what you get with many tube amps and it’s exactly what Carver wanted to simulate."

[anthonyTD]

The wiper of the pot usualy goes to the input of the amplifier, Agreed ? thus varying the pot, also varies the resistance of the ampliers front end or input, taking it nearer, or further away from Ground!
A passive attenuator doesn't present a "low and varying" input impedance to the first stage of a power amp - it presents its source impedance to the amplifier.
However, this could be an explanation to what people hear. Some power amps' distortion goes up when fed from higher source impedances.

[anthonyTD]

Therefore; by varying the pot, you're varying the resistance, or impedance that the source has to drive, and thus at low volumes, where the wiper of the pot is nearest to ground, your're literally making the front end of the amplifier harder to drive! I hope that makes sense.


Correct. That's the source impedance (or output impedance) of the pot, not its input impedance. Actually, the output impedance is the resistance above the wiper in parallel with the resistance below the wiper. A 10k pot's output impedance is 2.5k at its maximum, but drops towards zero at both ends of its travel (more accurately, zero plus the source impedance of whatever is driving it).

[Clive]

With an AVC does the impedance seen by the source increase as the higher turns are used? I recall they differ from pots.

[Macca]

That was indeed a very helpful article ... and easier to follow than many.

I found this paragraph very interesting but am curious what exactly the 'substantial effect on the frequency response' would be (i.e. how it would sound) Don't know if any tube amp designers would care to clarify/comment.

"to simulate the sound of a tube amp in his Sunfire solid-state (transistor) amplifiers, famed designer Bob Carver added a “current mode” switch that placed a 1-ohm resistor in series with the output devices. Of course, this violated the 1-to-10 minimum ratio of output impedance to expected input impedance that we discussed above, and thus had a substantial effect on the frequency response of the connected speaker, but that’s what you get with many tube amps and it’s exactly what Carver wanted to simulate."

I think that because they use output transformers a valve amps frequency output will vary with the load it sees from the speaker.

[anthonyTD]

First of all; the speaker load is a constant variant, due to the varying signal frequency it has to deal with in musical content,, so both types of amplifiers will put out diffrent amounts of power into the load throughout the frequency bandwidth, due to this ever changing load impedance of the speaker, ofcourse, the affect will vary depending on how good the speaker is, but dont be fooled into thinking one topolgy is perfect at driving a speaker over the other, I have gone into this in some detail in various other posts over the years here.Yes, you can introduce some form of crude impedance, by inserting a resistor in the output of a solid state amp in an effort to similate what a valve amp's output does when connected to a speaker, but its not an accurate way of describing the diffrences between how a solid state amp deals with a speaker versus a valve amp, I just see it as an attempt to bias non technical folk into thinking that solid state amps are automaticaly better than valve amps, which is far from the case in many situations.
I think that because they use output transformers a valve amps frequency output will vary with the load it sees from the speaker.

[anthonyTD]

https://forum.audiogon.com/discussions/slagle-avc-modules-lightspeed-attenuator
With an AVC does the impedance seen by the source increase as the higher turns are used? I recall they differ from pots.

[Macca]

In the Carver challenge he used null testing to tweak his SS amp so it sounded like the valve amp. He succeeded but I don't think the resulting SS amp was unconditionally stable as a result.

[anthonyTD]

The input resistance/impedance of the pot, ie; the part that the source see's [usualy the full resistance of the pot] as you and I both seem to agree on" is not the problem, where the issue some describe as some passives sounding lifeless, IMHO, its all to do with the lowering of the amplifiers input resistance, or impedance, by the wiper of the Attenuator being nearer to ground at low, to medium volumes!
No; changing the position of the pot's wiper has very little effect on the impedance seen by the source, eg CD player. Yes, the power amp's input impedance is in parallel with the lower half of the pot, but as long as the power's amp's input impedance is considerably higher than the pot's resistance there won't be much impact.
Take for example a 10k pot and a power amp with an input impedance of 100k. With the pot turned fully down the CD player sees a load of 10k. With the pot turned to half it's resistance value (which is more than half way round for a log pot) the CD player sees a load of 5k plus 5k in parallel with 100k. That works out at 9.8k, ie very nearly 10k.
With the pot turned up full the CD player sees a load of 10k in parallel with 100k. That works out at 9.1k, ie still very nearly 10k, so the load impedance seen by the source (the CD player, for example) doesn't change very much at all.
When I referred to "the source impedance" earlier I was referring to the source impedance, aka the output impedance, of the pot.

[anthonyTD]

No, the input of the power amp, by your own explanation is now nearer 1k, not 100k, at low volume, due to the low resistance imposed on it by the pots wiper position,with respect to ground!
I presume by "amplifier" you're referring to the power amplifier. If so, let's look at some figures. Using the same example as above with a 10k pot and a power amp with a 100k input impedance, with the pot down near the bottom at say, 10%, the pot has a resistance of 9k above the wiper and 1k below it. In that instance the pot has an output impedance of 1k in parallel with 9k, which works out at 900 ohms. The input impedance of the power amp is still 100k. The load the CD player sees is (near as dammit) 10k.

[mikmas]

I think that because they use output transformers a valve amps frequency output will vary with the load it sees from the speaker.

I see (kind of) .... so how does that manifest itself in terms of what we hear?
The author of the article refers to a "substantial effect on the frequency response of the connected speaker" - would that be:

- a frequency imbalance?
- distortion?
- noise?

... none of the above?

[anthonyTD]

We'l just have to agree to disagree! :)
No, it isn't - it remains at 100k.
At this point perhaps this particular discussion is over, lest it descend into "yes it is, no it isn't".

[anthonyTD]

Hi Mike,
See post 241, it may answer in part. :)
A...
I see (kind of) .... so how does that manifest itself in terms of what we hear?
The author of the article refers to a "substantial effect on the frequency response of the connected speaker" - would that be:

- a frequency imbalance?
- distortion?
- noise?

... none of the above?

[Marco]

At this point perhaps this particular discussion is over, lest it descend into "yes it is, no it isn't".

Thing is, one of you must be right, and the other wrong [providing you're both talking about the same thing], as what you're discussing isn't subjective;)

In that respect, it would be good to find out which.

Marco.

[Barry]

The effective input impedance of the amplifier, as seen by a source up-stream of the potentiometer will be: (resistance between the wiper and ground) in parallel with 100K [the quoted input impedance of the amplifier]) + the remaining resistance of the potentiometer (between the wiper and the source terminal).

For the example given, where the wiper divides the total resistance range into 1K (between wiper and ground) + 9K, the effective input impedance as seen by a source will be (1K // 100K) + 9K = 0.99K + 9K = 9.99K. So virtually unchanged from 10K.


In the other case where the wiper divides the 10K resistance range into 9K + 1K (so 90% full voltage, or about -1dB), the effective input impedance as seen by the source will be (9K // 100K) + 1K = 8.26K + 1K = 9.26K. Again, not too far removed from 10K.


I think the confusion might have been due to the ambiguity of exactly where the 'input' impedance is being calculated.

[anthonyTD]

Indeed!
Thanks Barry,:)
Which was why I think both of us decided to agree to disagree, the main thing that our discusion has hopefuly acheived is helping people understand the main diffrences between active, and passive preamps, and how attenuation is applied, and their posible affect on diffrent combinations of equipment, even if some of it ended up a bit confusing!
A...
.




I think the confusion might have been due to the ambiguity of exactly where the 'input' impedance is being calculated.

[Marco]

I'd just like to touch again on something Alan posted earlier, regarding cables, and specifically his comment on: "driving the capacitance of interconnect leads" See key bits in bold:


Now keeping things simple, imagine the output of the passive/active preamp driving the capacitance of the interconnect leads:

With a passive with its associated larger output resistance the hf frequency response is always curtailed, very much in the ultrasonic range (to our ears) in virtually all cases, BUT even though we cannot hear the frequency where the response falls there is always an alteration to the phase response.

With an active preamp with a much lower output resistance there is much more drive to charge/discharge the capacitance of the interconnect leads, so the hf response is affected much less, with the correspondingly smaller effect on the phase response.

So my hypothesis is that the missing bit with the passive approach is phase accuracy.

Alan mentions phase accuracy as possibly being the 'missing bit' with passives, which may well be the case, but what about the respective abilities of both passive and active designs at, as he says, driving the capacitance of interconnect leads, and passives curtailing the HF frequency response, as a result of them having a higher output resistance?

Could that be a contributory factor for the 'soft' sound, lacking in drive and punch, some of us perceive with passives, compared with their active counterparts?

Certainly experience tells me that passives are much fussier than actives about cables, both in terms of length and capacitance.

In that respect, using ones that are too long, and/or too high in capacitance, softens the sound. That's what I heard repeatedly during my experiments with the Goldpoint (and other passives I tried), which is why I ended up using 0.5m interconnects of the lowest capacitance I could find.

But....Perhaps no matter how short or how low in capacitance the accompanying cables are, ultimately they act as the defining limiting factor in passives, by curtailing the HF frequency response to a degree, still audible enough to soften the sound?

Actives, despite having their own issues, negate that problem by having a much lower output resistance, and so simply don't suffer from that issue to anything like the same degree, by 'driving' cables better, and in turn negating the propensity to soften the sound.

Just throwing that one out to folks for consideration!:)

Marco.

[anthonyTD]

From my point of view, as I said, Alan has a point where he mentions impedances having an affect, which was the point I was trying to make, if you put a conventional Attenuator in the front end of an amplifier, it will be the dominant factor as far as the input sensitivity of the amplier is concerned, when you vary the pot, you will be varying the input sensitivity of the power amp, due to the way the Attenuator is connected to the amplifier! And yes, I do believe that while this is going on, any cables that are connected between the amplifier, Attenuator, and Source to a degree" will also have an affect.
I'd just like to touch again on something Alan posted earlier, regarding cables, and specifically his comment on: "driving the capacitance of interconnect leads" See key bits in bold:



Alan mentions phase accuracy as possibly being the 'missing bit' with passives, which may well be the case, but what about the respective abilities of both passive and active designs at, as he says, driving the capacitance of interconnect leads, and passives curtailing the HF frequency response, as a result of them having a higher output resistance?

Could that be a contributory factor for the 'soft' sound, lacking in drive and punch, some of us perceive with passives, compared with their active counterparts?

Certainly experience tells me that passives are much fussier than actives about cables, both in terms of length and capacitance.

In that respect, using ones that are too long, and/or too high in capacitance, softens the sound. That's what I heard repeatedly during my experiments with the Goldpoint (and other passives I tried), which is why I ended up using 0.5m interconnects of the lowest capacitance I could find.

But....Perhaps no matter how short or how low in capacitance the accompanying cables are, ultimately they act as the defining limiting factor in passives, by curtailing the HF frequency response to a degree, still audible enough to soften the sound?

Actives, despite having their own issues, negate that problem by having a much lower output resistance, and so simply don't suffer from that issue to anything like the same degree, by 'driving' cables better, and in turn negating the propensity to soften the sound.

Just throwing that one out to folks for consideration!:)

Marco.

[Marco]

Understood, Anthony. I'm just wondering though, ultimately which effect will be more audible (although of course it may vary from system to system): the former, as you describe, or the limiting factor of the interconnects, in terms of a passive's inability to 'drive' them as efficiently?

After all, when all said and done, the signal his to pass through those cables to the next stage of the amplification chain (the partnering power amp), and so any bottleneck present there is bound to have an influential effect.

If HF frequency response, as Alan says, is being curtailed to any notable degree, it'll always be heard on a good system:)

Marco.

[anthonyTD]

Hi Marco,
I think It may be better to first get others points of view on this, I just feel sometimes I am banging my head mate, we can all refer back to the text books, and quote how things should work, but there seems to be few of us here these days who are willing to think outside of the box, and look at other aspects that could posibly have an affect, rather than taking the stance, if you cant measure it, its not happening, and therefore; those who experience these affects, are somehow deluded, or fooling themselves, I try very hard not to do that, which is why I usualy keep my explanations as non technical as posible, once you start spouting equations, and textbook speel, you lose the attention of posibly 90% of your intended audience! :doh:
Understood, Anthony. I'm just wondering though, ultimately which effect will be more audible (although of course it may vary from system to system): the former, as you describe, or the limiting factor of the interconnects, in terms of a passive's inability to 'drive' them as efficiently?

After all, when all said and done, the signal his to pass through those cables to the next stage of the amplification chain (the partnering power amp), and so any bottleneck present there is bound to have an influential effect.

If HF frequency response, as Alan says, is being curtailed to any notable degree, it'll always be heard on a good system:)

Marco.

[Marco]

Yeah, mate, I get that and agree. However, you have a way of putting technical points across that any layman of reasonable intelligence can understand and appreciate, as I do (mostly), so I'm sure that also applies to other folks here:)

Ultimately though, there's a limit to the amount of people who are interested enough in this particular subject, to go into it in such detail. Most just want to discuss how stuff sounds, rather than why. However, I think it's good having these types of discussions, because as you say, thinking outside of the box, with any aspect of audio, is the only way you learn and make progress!

Marco.

[anthonyTD]

:)
Yeah, mate, I get that and agree. However, you have a way of putting technical points across that any layman of reasonable intelligence can understand and appreciate, as I do (mostly), so I'm sure that also applies to other folks here:)

Ultimately though, there's a limit to the amount of people who are interested enough in this particular subject, to go into it in such detail. Most just want to discuss how stuff sounds, rather than why. However, I think it's good having these types of discussions, because as you say, thinking outside of the box, with any aspect of audio, is the only way you learn and make progress!

Marco.

[Firebottle]

Just to reiterate I was hypothesising that the change in the phase response could be what makes the sound appear 'soft', if we stick with that word.

In any system that has a decreasing frequency response there will be an associated phase response change, however small.
Here is a plot to show a typical change in phase with gain (aka loss at higher frequencies) :

http://www.adsantec.com/wp-content/uploads/2018/01/Picture5.png

The human hearing is incredibly sensitive to small changes in phase, that is how we hear the direction of a possible threat.
What I am suggesting is that with a small phase change say on the percussive parts of music, the impact of such may be interpreted as 'soft' possibly.

Just trying to think of associated effects, rather than the obvious (and readily heard/measured) curtailment of frequency response.

[Macca]

I thought the opposite was true and that we are not very good at picking up on phase errors?

Also that any phase error would only exist over a very narrow frequency band and therefore be unlikely to be audible?

[Firebottle]

I thought the opposite was true and that we are not very good at picking up on phase errors?

I think that is the point, that we can't put our collective fingers on what the difference is caused by phase errors.

[Macca]

I think that is the point, that we can't put our collective fingers on what the difference is caused by phase errors.

Both sides of argument well presented here http://www.silcom.com/~aludwig/Phase_audibility.htm

Another question is, that assuming the loudspeakers have phase errors, and most do, would this not swamp any phase error from the passive pre-amp? And therefore the issue would be the same with any type of pre-amplifier unless using speakers with perfect phase.

[Primalsea]

I wonder if gain structure has a lot to do with it. If you considered the circuits of the source, preamp and power amp as one large compound circuit and then broke down where gain and attenuation occurred along with how much of each in this one compound theoretical circuit, I wonder if there will be some correlation between perceived grain and the gain structure?

[Pharos]

Loudspeakers have comparatively poor phase, and the best are referred to as 'liner phase' which actually is a misnomer, 'constant phase' being more accurate.

The top loss above may affect transient perception.

[mikmas]

I wonder if gain structure has a lot to do with it. If you considered the circuits of the source, preamp and power amp as one large compound circuit and then broke down where gain and attenuation occurred along with how much of each in this one compound theoretical circuit, I wonder if there will be some correlation between perceived grain and the gain structure?

I've been musing about exactly that every time I dip into this thread.

I currently have an integrated DAC/amp but up 'til a year ago used a Quad 405-2 with a passive 'pot in a box' and found the sound absolutely spiffing. This came about following suggestions I came across here and on other forums and was based on the notion that an active pre was pretty much superfluous given the sensitivity of the Quad (0.5v) and the high output of contemporary sources ... such as the Q-Dac I was using and RPi/IQaudio combo.

Plenty of drive and vitality - no 'softness' - and no 'grain' that I was aware of (whatever that nebulous word means....)