Passive Preamps

[bob4333]

Can anyone offer a recommendation on a passive preamp?

Ideally it should have 4 inputs plus a tape in / out. It'll also need to be able to accommodate a pass thru although I guess I could just use an input and turn the vol control up to max (right?). A remote control would be useful but I could live without it if there are other benefits.

I need it to just be audibly invisible. No colouration, neither adding nor taking anything away. This would be going straight into my Musical Fidelity A5cr Power Amp.

I'd also be grateful to hear from anyone who's tried a passive and found it didn't meet their needs. For what reason?

Many thanks, Bob

[hifinutt]

well I am surprised to see a request for a passive after using an arc ls 27 which is on my wish list sometime [ having had a few arc pre amps ] . it would take a very good passive to beat that . also passives with HTB are very very rare . think i saw a MFA once with it

just for interest the freya has loads of inputs and is incredibly transparent , more so than my pre 3 vbs . its a passive . it would be interesting to compare it to your LS27 . there is one here and not too far from you !!

https://theartofsound.net/forum/showthread.php?63299-Schiit-Freya-passive-pre-amp

[Macca]

Nelson Pass DCB1 - you'd have to build it yourself or get someone to build it though. Not commercially available as a built unit. But you could specify as many inputs as you wanted plus a pass through. Passive with a buffer so you have to plug it in but there is no gain stage.

[Firebottle]

Nelson pass DCB1 is amazingly transparent, depending on the volume control element.
Just to provide more information this is a potentiometer or stepped attenuator followed by the DCB1 buffer stage.

Other buffer stages can be used, there are valve based buffer stages available as well, from other vendors.

A stepped attenuator of sufficient quality will give the best performance, a lot use the Khozmo series attenuator, an alternative that is a little less expensive but of equal transparency is the Acoustic Dimension stepped attenuator.

Both Khozmo and Acoustic Dimension are available with remote control, though the AD unit is a fair bit cheaper.

[STD305M]

I love my dcb1, its now on it's 6th carnation and each upgrade has been an eye opener.

It's a very adaptable machine with lots of upgrade paths and a variation of configurations

Steve..

[Pigmy Pony]

I love my dcb1, its now on it's 6th carnation and each upgrade has been an eye opener.

It's a very adaptable machine with lots of upgrade paths and a variation of configurations

Steve..

I'm intrigued by this - is the DCB1 expensive to buy, are they only kit form, and if so how hard are they to make, bearing in mind I have sausage fingers and zero experience with a soldering iron. The idea of getting a pre amp for not too much money, then upgrading as funds become available is quite appealing.

[smangus]

I'm intrigued by this - is the DCB1 expensive to buy, are they only kit form, and if so how hard are they to make, bearing in mind I have sausage fingers and zero experience with a soldering iron. The idea of getting a pre amp for not too much money, then upgrading as funds become available is quite appealing.Snap! I just did this , see the build thread. With no electronics experiance at all and it has worked out fine . Still running in but certainly showing potential even in stock form. If you are willing to then I would say have a go as there are plenty of people here and on DIY audio who would help out. I sent to board to Alan for a bit of numpty trouble shooting but apart from that was fairly straightforward.

Sent from my SM-G950F using Tapatalk

[STD305M]

Hi Steve

They aren't to bad to build, ive built 6 so far and there are a couple of others on aos who have built them too.

Price wise somewhere between £460 and £600 depending on spec, fit and finish.

Regards Steve

[Bigman80]

Yup, best pre I've personally heard and if you invest in it, it gets better and better.

If you aren't 100% on it, Firebottle is more than capable of putting these together.

[Light Dependant Resistor]

Is a bake-off needed ?

[struth]

Bake off s are always needed.

[Mikeandvan]

Nelson pass DCB1 is amazingly transparent, depending on the volume control element.
Just to provide more information this is a potentiometer or stepped attenuator followed by the DCB1 buffer stage.

Other buffer stages can be used, there are valve based buffer stages available as well, from other vendors.

A stepped attenuator of sufficient quality will give the best performance, a lot use the Khozmo series attenuator, an alternative that is a little less expensive but of equal transparency is the Acoustic Dimension stepped attenuator.

Both Khozmo and Acoustic Dimension are available with remote control, though the AD unit is a fair bit cheaper.

Where are the Acoustic dimension passives sold?

[Bigman80]

Is a bake-off needed ?We did one.

The DCB1 is the best preamp Ive heard.

We used the big one in the pic.

The write up of the bakeoff was put here:

http://audioaddictsforum.com/thread/564/ldr-preamp-listening-test
https://uploads.tapatalk-cdn.com/20190325/0eba2f38681f0cd6c06f3d20d8036ad1.jpghttps://uploads.tapatalk-cdn.com/20190325/18aad313b75521f74560158783222b5a.jpg

[Light Dependant Resistor]

That's a bit opposite to other forums, https://www.stereo.net.au/forums/topic/260371-2019-stereocoffee-ldr-preattenuator-kit/
but thanks. From my own experience powering with the recommended 12vAC as in the above review rather than DC 12v is the way to go.
The technical reasons are that only one half of the mosfet rectifier is used with DC. Maybe await Marco's review, as his is 12v AC

[Barry]

That's a bit opposite to other forums, https://www.stereo.net.au/forums/topic/260371-2019-stereocoffee-ldr-preattenuator-kit/
but thanks. From my own experience powering with the recommended 12vAC as in the above review rather than DC 12v is the way to go.
The technical reasons are that only one half of the mosfet rectifier is used with DC. Maybe await Marco's review, as his is 12v AC

:popcorn: :popcorn: :popcorn:

[walpurgis]

I think Martin has one tucked away too that has yet to see the light of day. :)

[walpurgis]

I'm quite tempted to try one of the relay passive pre-amps that have been cropping up on Chinese ebay sites, but I don't want remote control which most seem to include. Strangely, the few that are manual only are dearer.

I thing Alan (Firebottle) has been trying one.

[Light Dependant Resistor]

I think Martin has one tucked away too that has yet to see the light of day. :)
Its a very early edition, which needs updating to latest spec,which I am happy to do.


ie LDRs were NSL32SR2S vs NSL32SR3 and over 7 years of development following.

[Light Dependant Resistor]

:popcorn: :popcorn: :popcorn:
Like all good things, it will happen, I am updating Marco's main board and posting it tomorrow from NZ.... so about 2 weeks from now ...

[Firebottle]

Where are the Acoustic dimension passives sold?

http://www.acoustic-dimension.com/attenuators/attenuators-main.htm

[Bigman80]

That's a bit opposite to other forums, https://www.stereo.net.au/forums/topic/260371-2019-stereocoffee-ldr-preattenuator-kit/
but thanks. From my own experience powering with the recommended 12vAC as in the above review rather than DC 12v is the way to go.
The technical reasons are that only one half of the mosfet rectifier is used with DC. Maybe await Marco's review, as his is 12v ACCan I ask, did they purchase it from you prior to sharing their thoughts?

Both the DCB1 and the LDR stereo Coffee are available in kit form. Therefore you are reliant on the build itself, rather than the idea to perform and of course, there are other ways to do things. If you don't agree with the was the board was powered, I understand that but this build was done by a pro.

Marco's opinion on what sounds good has differed somewhat to mine over a couple of pieces equipment so maybe I won't wait for Marcos review [emoji38] He was right about mains and things to improve the system though, credit where it's due!

Its only another opinion, LDR, so don't sweat it.

[Light Dependant Resistor]

The requirements of the kit are to be ideally powered from 12v AC, the main board can also be powered from DC with minimum voltage 12v and maximum 18v DC
From the instructions:

Powering
AC 12V
You will need a 12vAC supply - this is about the easiest, observing the diagram
note AC connection is using each side of the blue receptacle
taking care neither can touch
Powering DC
whereas DC is using one of the blue block receptacles for positive and the
green block for negative - then ground. You will need with DC to know its
polarity, which can be tested with a multimeter
If using DC the kit is very versatile with power, you can use a 12v battery with
a solar panel to charge, or DC up to 18v.

I will update Edwards board, to same spec as Marco's, there should then be little difference when battery powered at the lower 12v specification.
This is as a result of new efficiencies in the middle part of the board. voltage drop from the tab of the P channel mosfet to series anode out is 3.6v
and wiper to series anode will with Edwards board be just on 6v which is a healthy figure

[julesd68]

I'm quite tempted to try one of the relay passive pre-amps that have been cropping up on Chinese ebay sites, but I don't want remote control which most seem to include. Strangely, the few that are manual only are dearer.

I've got one Geoff and am very happy with it indeed - it really is incredibly transparent.
The only problem was the hopeless remote control design but sorted in the end.

The seller has quite a range of different models with and without remotes. Found him very good to deal with.

https://www.ebay.co.uk/itm/Volume-Remote-Control-Relay-128-Steps-Exponential-Constant-input-impedance-4-CH/143087087145?hash=item2150a7ae29:g:EZQAAOSw6CJbCmL 8

[Ian7633]

I can only echo what Julian says, brilliant little pre for the money and a woeful remote but easily sortable.

[Colin2040]

For what its worth I have had a Khozmo, Glasshouse and currently Schiit Saga. Out of them all I think I preferred the Glasshouse it was the TVC version bot overall I like the Schiit for its SQ and easy use with remote. Plus valve buffer that I can play with.

Colin

[bob4333]

Some passives I've seen have not much more than a potentiometer inside, some seem to have a fair bit of circuitry and a power supply. If it's truly passive can someone (gently) explain why? (I can understand a supply for a passive with a remote)

[Firebottle]

Using the description passive is inferring there is no gain, i. e. that the unit will only attenuate.

If there is a unity gain buffer stage for impedance matching then that still applies, also if there is some sort of remote control.
For a buffer or remote then a power supply is required to operate, even though there is no overall gain.

[Macca]

Some passives I've seen have not much more than a potentiometer inside, some seem to have a fair bit of circuitry and a power supply. If it's truly passive can someone (gently) explain why? (I can understand a supply for a passive with a remote)

In some situations having the buffer will help match with the power amp being used and give better sound quality over what you will get with a passive pot alone.

[Light Dependant Resistor]

In some situations having the buffer will help match with the power amp being used and give better sound quality over what you will get with a passive pot alone.

Observing passives can also be opto coupled, that is arguably the better approach not having a conventional pot, or input switching in the audio signal path.

[Mikeandvan]

For what its worth I have had a Khozmo, Glasshouse and currently Schiit Saga. Out of them all I think I preferred the Glasshouse it was the TVC version bot overall I like the Schiit for its SQ and easy use with remote. Plus valve buffer that I can play with.

Colin

wow, the sagas are cheap right? And you say better than the KHOZMO? mind you what is 'better'?

[bob4333]

Using the description passive is inferring there is no gain, i. e. that the unit will only attenuate.

If there is a unity gain buffer stage for impedance matching then that still applies, also if there is some sort of remote control.
For a buffer or remote then a power supply is required to operate, even though there is no overall gain.

Thanks for the explanation Alan. Can this truly be said to have no audible effect on the purity of the incoming signal compared to what comes out? I'm not trying to be pedantic over this, just trying to understand. This is a long way from my knowledge base.


In some situations having the buffer will help match with the power amp being used and give better sound quality over what you will get with a passive pot alone.

I can understand the benefit in matching. But does this move away from what can properly be called "passive"? Don't know - again just trying to understand.:scratch:

[Light Dependant Resistor]

Thanks for the explanation Alan. Can this truly be said to have no audible effect on the purity of the incoming signal compared to what comes out? I'm not trying to be pedantic over this, just trying to understand. This is a long way from my knowledge base.

No a buffer will always involve moving away from the purity of the incoming signal, compared to the source. The source is a hard act to follow in a nutshell


I can understand the benefit in matching. But does this move away from what can properly be called "passive"? Don't know - again just trying to understand.:scratch:

Yes any buffer is a active stage, and even if unity gain with voltage, its aim is to provide current gain, and is not passive.
A passive attenuator uses the audio signal itself to attenuate via variable resistance. Resistance ( whilst futile ) itself has very little
detriment to audio signals. The exception being where resistors are very high in value and what is called Johnson noise contributes
http://www.resistorguide.com/resistor-noise/

However the use of contacts including potentiometer internal parts cause distortions. The best method of attenuation remains to remove contacts altogether
by using opto coupling.

The arguments for using buffers arise from impedance mismatching, which are better solved to then happily use passive attenuation, by using a source with low impedance capability
and at the same time a power amp with reasonable sensitivity and resistive loading. A great example of the perfect recipe for passives is the Quad 306 providing 22k or 20k loading
depending oin which year, and 375mv sensitivity for full output.

If all power amps were specified this way the use of active preamps, ( other than dedicated phono stages ) would disappear, as well as buffers, both of which add distortions to audio.

[AJSki2fly]

Nail on the head.

If you want a good simple and high quality cost effective passive, then a Tisbury is hard to beat IMHO.

[Bigman80]

Link there for those who want a very knowledgeable, independent, fact based opinion on the use of LDR in Preamps:

https://www.neurochrome.com/tortuga-audio-ldr3/

[Light Dependant Resistor]

Link there for those who want a very knowledgeable fact based opinion on the use of LDR in Preamps:

https://www.neurochrome.com/tortuga-audio-ldr3/


My opinion on Tom's findings are simply that the anode and cathode of the LDR led are driven with as far as I know digital signal waveforms in the Tortuga and what is measured results from that method.
Tom's measurements are exactly as I would expect

LDR's are analog current devices needing precise control of 2ma of current or less. The correct approach is to
1. not directly ground the cathode
2. Place the volume attenuation following the cathodes
3 Use circuitry normally seen in high bandwidth amplifiers ie common gate pchannel and n channel mosfets in particular
4 Use a very specialised rectifier having current control in its diode branches, and be mosfet and thyristor based.

If its any use I am listening to it right now, the board on its way ( sorry a day late ) to Marco.

[Marco]

Measurements, shmeasurements.... What does it sound like in the real world, with music? Ultimately, that's how I judge things!:)

Marco.

[Marco]

If its any use I am listening to it right now, the board on its way ( sorry a day late ) to Marco.

No worries, mate. Once I receive it, we'll get the [long promised] review underway, and I'll report my honest opinion on how it compares with the Croft, in the context of my system, and indeed all other preamps, passive and active I've heard to date, using MUSIC as the arbiter, not measurements....;)

Marco.

[Bigman80]

Apologies, Chris.

That post should have had "independent" in it, as without it, reads a little aggressive. That wasn't the aim.

Obviously the way you have yours designed will differ to that of the Toreaga but I felt the article was "more information" and worthwhile sharing.

If you do manage to send over an optimised unit (as discussed), whatever the outcome a future bakeoff brings, there's never really a one size fits all solution to any part of the chain. I'd never go back to the "pot in a box" approach aka the Tidsbury.

I've always had the same ethos about the system, if I put something in the system and its better than the piece of equipment I have, I'll do my best to either buy it or build it. Hence my "Boxswapper" approach over the last few years.

If the LDR ousts the DCB1, you'll get my money. Simple.

[Bigman80]

Measurements, shmeasurements.... What does it sound like in the real world, with music? Ultimately, that's how I judge things!:)

Marco.We all do Marco. The claim of SA's adding distortion and LDRs not, needed to be challenged.

Ultimately, as I've said elsewhere, I actually think a bit of distortion is not always a bad thing. Look at valve amps!

[Marco]

I've always found 'pots in a box' to act as a significant bottleneck [robbing music of vitality and 'life'], in comparison with the best active designs and LDRs, *if* the partnering power amp, and system as a whole, hasn't been designed around such passive devices, in which case they can work well.

However, simply inserting a 'pot in a box' into a system, without the necessary supporting infrastructure, is very hit and miss and likely to end in sonic disappointment.

Marco.

[Marco]

We all do Marco. The claim of SA's adding distortion and LDRs not, needed to be challenged.

Ultimately, as I've said elsewhere, I actually think a bit of distortion is not always a bad thing. Look at valve amps!

Indeed, although ALL amps distort, to some degree, and in different ways;)

If you want to talk about distortion, look at vinyl, never mind valve amps! And yet, done well, it can produce some of the most beautiful sounds we hear....

Marco.

[Bigman80]

Indeed, although ALL amps distort, to some degree, and in different ways;)

Marco.Oh, absolutely. Yet in a recent A/B test where I removed my preamp for a direct connection to the source, I far preferred it with the Preamp in situ!

[Marco]

Not surprised, simply because your system hasn't been designed around a 'pot in a box'. I heard the same as you, in my system, and reached the same conclusion. That doesn't mean it can't work well, though.

Btw, on (slightly) related subject, I've been reading some of your views on AA about valve amps, and your conclusion that they can't 'do bass' as well as SS designs...

Well, that only applies up until you spend sufficient money (around £5k and above) on a top-notch, reasonably powerful (say 30-50W) push-pull valve amp, featuring the use of large output-valves, such as KT120s or 150s, and good enough (and big enough) mains and output transformers.

My TD Copper amp, and others like it, such as the John Wood, fit the bill. Do that, and crucially, *match* the valve amp properly with the right speakers, and the bass produced will be just as good as that from your Krell, trust me!;)

Marco.

[Bigman80]

Not surprised, simply because your system hasn't been designed around a 'pot in a box'. I heard the same as you, in my system, and reached the same conclusion. That doesn't mean it can't work well, though.

Btw, on (slightly) related subject, I've been reading some of your views on AA about valve amps, and your conclusion that they can't 'do bass' as well as SS designs...

Well, that only applies up until you spend sufficient money (around £5k and above) on a top-notch, reasonably powerful (say 30-50W) push-pull valve amp, featuring the use of large output-valves, such as KT120s or 150s, and good enough (and big enough) mains and output transformers.

My TD Copper amp, and others like it, such as the John Wood, fit the bill. Do that, and crucially, *match* the valve amp properly with the right speakers, and the bass produced will be just as good as that from your Krell, trust me!;)

Marco.Well, if I were to spend £5k on a Valve amp I'd expect it to do bass right, as well as everything else!

Thing is you can get solid state amps (see Krell) that does everything right (imo) for £1.5k so having valves, and there continued expense in the replenishment of valves means having a Valve amp of sufficient quality no longer appeals to me.

Your amps and those by the TD are what I'd call, prestige items. Not for us working class types lol.

Seriously, I don't doubt the performance but, don't doubt the performance of the Krell, especially now that I've dealt with a few things like speaker cables and giving the speakers (uncouth as they may be, Macca [emoji6]) better stands to help.

The only thing I lack is the room to really get the very last bits out of this system.

Putting the system together, I didn't have a plan, hence the multiple boxes passing through my house. What I did was listen to as much as I could and try to find what I wanted from both listening to those pieces and the pieces other people have in their systems. I don't think there's many folks who have been as active in their pursuit of equipment to listen to as I have!

The preamp situation was a development. At every stage, when one piece was improved, it revealed an issue else where. As Hans Beekhuyzen said, "if one piece of the chain is below standard, it will be revealed". He's spot on and as the source and amplification got better, the preamps were getting to be the weak link. I've tried possibly everything, in terms of type. TVC, AVC, Passive, Passive Stepped Attenuators, Valve Pre, Active SS Pre, Active SS SA's and LDR, The Truth Preamp - Not sure exactly what that was.

I found the DCB1 did everything I was looking for. Almost like it just captures the best bits from all of the previous preamps is tried.

From there, came the Krell which has revolutionised my listening experience. The Krell, being an absolute top class amplifier, enable (Finally) the use of Digital.

What I'd say to ANYONE starting on this journey is:

Get the best Preamp and Amplification you can from the off. WITHOUT that, nothing else can really show it's ability.

[Marco]

Can't really argue with any of that dude, and I'm sure that the Krell sounds great... My point was not to create or believe in absolutes: valves = soggy bass, SS = hard & soulless, digital = bright and hard, analogue = euphonic and coloured, etc, etc.

Quite simply, it's bullshit, as indeed you eventually find out from experience, once you hear any of the above at its best!:)

Marco.

[Bigman80]

Can't really argue with any of that dude, and I'm sure that the Krell sounds great... My point was not to create or believe in absolutes: valves = soggy bass, SS = hard & soulless, digital = bright and hard, analogue = euphonic and coloured, etc, etc.

Quite simply, it's bullshit, as indeed you eventually find out from experience, once you hear any of the above at its best!:)

Marco.No, absolutes can never be defined because there always one think bucks the trend.

I was talking from a perspective of the Budget in which most of are working. Obviously, as pieces get higher in quality, those parameters of performance with change. If I had £1.5k to spend, I don't think there's a Valve amp out there that would sufficiently compare to the Krell for my taste. BUT I am never one to say it can't happen.

[Marco]

I'd have to be a DIY job, not designed to be sold on, so that every penny was spent on where it mattered most, otherwise no.

Marco.

[karma67]

I'd have to be a DIY job, not designed to be sold on, so that every penny was spent on where it mattered most, otherwise no.

Marco.

Which brings us nicely back to John wood amps :)

[karma67]

Whilst we are on the subject of valve amps, Marco have you ever heard the gec kt88 valves and if so are they that much better than modern kt88s? I ask because I’m about to buy some.

[Marco]

Which brings us nicely back to John wood amps :)

Great amp. Don't know how he does it for the money asked!

Marco.

[Marco]

Whilst we are on the subject of valve amps, Marco have you ever heard the gec kt88 valves and if so are they that much better than modern kt88s? I ask because I’m about to buy some.

Yes, if they're good ones [professionally tested and measured to achieve the correct spec], they're *massively* better than modern equivalents, so much so you'd question whether they were the same valves, which of course they're not;)

However, how much are you paying for them? They're usually stupidly overpriced, baring in mind that any one of them could blow/fail at any time, such is the nature of the beast!:eek:

The best compromise between original GEC KT88s and modern equivalents are the original Winged-C Svetlanas, if you can find some, and which won't be cheap either. Those get you 90% of the way there:)

Marco.

[Bigman80]

I'd have to be a DIY job, not designed to be sold on, so that every penny was spent on where it mattered most, otherwise no.

Marco.Solely DIY. No help or payments for help at least!!.

Its not something I'll be doing lol

[Macca]

Thanks for the explanation Alan. Can this truly be said to have no audible effect on the purity of the incoming signal compared to what comes out? I'm not trying to be pedantic over this, just trying to understand. This is a long way from my knowledge base.



I can understand the benefit in matching. But does this move away from what can properly be called "passive"? Don't know - again just trying to understand.:scratch:

Yes it is. Ideally a passive pre-amp should be combined with a power amplifier that is optimised to be used with it. That's not a trivial ask as very few companies offer matching passive pre and power amplifiers.

But if you have a power amp you really like but it is not ideal with a passive then you have to look for other solutions. There really is no need for an active pre-amp with gain these days, no modern phono stage or DAC requires one.

I was using my Krell KSA50S with a passive pre, results were good but I felt there was a slight bit off softness and lack of sparkle to the sound, moving to an active with unity gain resolved that without losing the aspects I liked with the passive (sweetness, clarity).

[bob4333]

Turning out to be lots of "flavours" to what started as a simple "what if" type of question.

[Marco]

Yes it is. Ideally a passive pre-amp should be combined with a power amplifier that is optimised to be used with it. That's not a trivial ask as very few companies offer matching passive pre and power amplifiers.


Yup, and that's the crux of the matter:)

Marco.

[Bigman80]

Turning out to be lots of "flavours" to what started as a simple "what if" type of question.Ha! There's no one answer on this matey.

Buy an amplifier of unquestionable quality THEN get the preamp to suit. This is what I'd do if I'd started over.

[slaba]

Had a tisbury for a while just to lend it an ear but could never match it properly and used it only as pocket preamp on the go whenever needed. Then a friend brought back my long due 606ii and when I plugged both together something was definitely happening. Got myself an Audio Synthesis Passion and the Tisbury was instantly sold theres' is absolutely no competition possible between the two. Yes matching is everything when it comes to using a passive and my second system now sounds like it never did with just a meridian 563 dac hooked to a chromecast, Passion passive, Quad 606ii and BC1 speakers, I could not be happier. Talked to John at AS about it and he confirmed I had a winning comb. Now I'm all over hunting for another passive and just ran across this https://www.ebay.co.uk/itm/Passive-Pre-Amplifier-VISHAY-top-line-SMD-resistors-50-K-Ohm-24-Steps-RCA-XLR/254177026907 has anyone heard it? google doesn't come with much

[Macca]

Turning out to be lots of "flavours" to what started as a simple "what if" type of question.

Nothing's simple in hi-fi land.

Get an idea of the sort of presentation of the sound you like and work towards achieving that. A system that is technically perfect in every respect (if it existed) may not give the sound you want. So what use would it be to you?

[walpurgis]

I had a Tisbury and tried it with a variety of power amps. It worked, but I was never really happy with the sound. My twenty five quid Little Bear passive sounds way better.

[Lawrence001]

I had a Tisbury and tried it with a variety of power amps. It worked, but I was never really happy with the sound. My twenty five quid Little Bear passive sounds way better.Is that the one with the valves?

Sent from my BLN-L21 using Tapatalk

[bob4333]

Nothing's simple in hi-fi land.

................. A system that is technically perfect in every respect (if it existed) may not give the sound you want. So what use would it be to you?

None whatsoever. Agreed.

But I can remember the days when you dare not set foot outside the door without checking the numbers to see what would work with what. Then we went through a perceived phase of almost anything worked with anything: now I think we're back to having to pay a bit more attention to the numbers again.

Or maybe it's just me and I'm fishing in a different pond ...............

[Light Dependant Resistor]

None whatsoever. Agreed.

But I can remember the days when you dare not set foot outside the door without checking the numbers to see what would work with what. Then we went through a perceived phase of almost anything worked with anything: now I think we're back to having to pay a bit more attention to the numbers again.

Or maybe it's just me and I'm fishing in a different pond ...............

Paying attention to the numbers, more than ever as you say is the thing to do.
Some figures for considering. If contemplating

A passive attenuator then power amp sensitivity needs to be ideally below 1v and resistive loading 20k or greater, a Quad 306 is just the best specified being 375mv and 20k loading.
The 303, 405, 306, 606, 707, 909 all offer good specifications for passives. Why other manufacturers cannot also do this ... starts to get political... Wot ! politics in HiFi ?

Sadly HiFi dare I say is quite political in its own way, namely active pre amp manufacturers want to remain in business, so their or similar power amps are made with 2 volt sensitivity or higher, the
worst I have seen was 3.5v for full output, this automatically means one of two things matching the insensitive power amp with a active preamp or using a current buffer - either way they remain
in business reinforcing their equipment.

However phono preamps are still needed, and stand alone phono preamps make a lot of sense.

So my advice is to, hunt down those power amp sensitivity and resistive loading figures - if you want to use a passive ... er as you should. :)

[nigeh]

Hi,

Has anyone had good results using a passive Pre as a feed into a Valve Power amp? (2A3 stereo SE @ circa 3.5w)

If so which?

Thanks,

Nige

[Lee Henley]

Hi,

Has anyone had good results using a passive Pre as a feed into a Valve Power amp? (2A3 stereo SE @ circa 3.5w)

If so which?

Thanks,

Nige

I’ve used a Hattor into Audionote 2a3 SET monk blocks but they are high gain 6w versions, it works fine

Lee

[nigeh]

Hi,

Has anyone had good results using a passive Pre as a feed into a Valve Power amp? (2A3 stereo SE @ circa 3.5w)

If so which?

Thanks,

Nige

[Made in 1968]

One of the early Hi-Fi shows i attended was at Victoria Hotel, Buxton, Derbyshire. There was Russ Andrews with a Modded Leak 'Stereo 20' with his passive. If i remember it was driving modded 'ESL-57's & Garrard '301' . One of the best sounding systems i'd listen to, I sat in that room for hours without moving.. So yeah that indeed work.

[krugdoktor]

I use a Townshend Allegri+ http://www.townshendaudio.com/allegri/ into an Eternal Arts OTL http://www.audioclassica.de/de/EternalArts-OTL-Mark-2.html and get the best sound I ever had at home!