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SamJones
20-04-2008, 00:47
Anyone using class D amps? What's the general opinion here? I know they are considered crap in some circles but I've been quite impressed with the sound quality of some recent models with computer and DAC as source.

Ashley James
20-04-2008, 08:22
Sam, they're widely used in Car Audio, AV Processors and with companies like B&O, they aren't as good as the analogue Amplifiers, but they are better than some.

They're becoming popular with Studio Monitors too because a DSP chip can be used on the input to act as a crossover for the Sub and Tweeters and any tonal alterations deemed necessary. Since they output a digital signal, Class D modules for the amps make sense and it gives it all a USP.

The principal advantage is reduced power consumption and not needing expensive heatsinks, but there are insoluble problems.

Ash

jandl100
20-04-2008, 09:01
I've owned TacT/Lyngdorf SDAi2175 integrated and SDA2175 power amps, NuForce Ref 8 power amps, Veritas P400 power amp ... and even the little plastic Sonic Impact T-amp. All Class D of a sort. RRPs range from £30 to £3,000!

An amp on a chip :scratch: - but so what?
I think they are all wonderfully musical beasts. :)

Definitely recommend folks at least try them. Some folks like them, some folks don't (although it baffles me why anyone wouldn't!)

I paired a £30 10wpc T-amp with my Kharma Ceramique 3 speakers (rrp £5k) - wonderful!

Marco
20-04-2008, 09:49
Hi Sam,

Welcome to the forum :)

I've heard a few Class D amps, and they're quite muscial, as Jerry says, although a bit 'dry' for my tastes. There's nothing to touch pure Class A done well, in my opinion. Listening to something like a Sugden A21a, it has a way with music that you don't get any other power amplifier circuit - runs hot, though, and you'll always have limited power output, but in the right system Class A designs can be magical.

Marco.

Sand Dancin Donkey Walker
20-04-2008, 09:50
I have lived with 2 Class D amps

Channel Islands Audio D100 Mono Blocks, What surprised me with these was they have bags of power and would drive quite difficult load speakers without sounding like they were running out of steam. A very open and controlled sound with loads of drive for the bass.

I also had the RedWine Audio Sig 30.2 Now these baby’s really are special. I have to say very valve like in sound and presentation. A nameless person didn't actually realise he was listening to the RedWine amp rather than my normal Almarro 50125. One big advantage of the RedWine is they are Battery Powered and are disconnected from the mains during use. Therefore no mains to bugger up the sound.

I was impressed with both of these amps, and would recommend anyone to at least give Class D a try. they have come a long way recently and are worthy of consideration

Andy - SDDW

anthonyTD
20-04-2008, 09:52
I've owned TacT/Lyngdorf SDAi2175 integrated and SDA2175 power amps, NuForce Ref 8 power amps, Veritas P400 power amp ... and even the little plastic Sonic Impact T-amp. All Class D of a sort. RRPs range from £30 to £3,000!

An amp on a chip :scratch: - but so what?
I think they are all wonderfully musical beasts. :)

Definitely recommend folks at least try them. Some folks like them, some folks don't (although it baffles me why anyone wouldn't!)

I paired a £30 10wpc T-amp with my Kharma Ceramique 3 speakers (rrp £5k) - wonderful!

hi jerry,
i have built a few versions using the tri-path chips and their performance have been very acceptable,and like ash mentions there are certain aspects of their design that make sense in using them in certain aplications, but there are also compromises that make some purists cringe!!!
anthony...;)

jandl100
20-04-2008, 10:06
but there are also compromises that make some pureists cringe!!!
anthony...;)

Fair enough - I'm not a techie. I just listen. And to me there is much sonic merit in the Class D approach - of the Class D amps I have heard there is definitely a sonic resemblance, a distinctive "Class D sound" - "fluid musicality" perhaps sums it up - along with "musical coherence", the musical presentation somehow seems more of a piece than with some other solid state amps which can seem to chop music up into separate components (if you know what I mean! :)).

I've heard slightly higher rez sounds, and perhaps as a result the soundstaging can be a little generic. But that's being a bit picky - there are some fine audiophile sounds to be had from this type of amp, imo.

Mr. C
20-04-2008, 10:33
The only way to make a switching amplifier work properly (IMHO) is to use the module as an output stage, and creat a fully discrete front end. (or design your own!)
Some modules used on chip fets, these produced some cracking results and with reasonable power (80W rms) at 0.001% THD.
Some are dry ( most mass produced units) and can be clinical too.
This is no small part to the power supply, imho a linear PSU is far more sonically preferable to smps. We have own own transformers custom built for the specific application. More to it than just a psu I would agree, (however as with anything that works, proper design/lay-out,testing and component selection pays dividends)
Switching amps can be pretty special, as quality SS are (Dartzel). Never been that struck on all class 'a' designs (Pass labs X350/600 owner too) they do certain things very well again, yet far short in the total coherence states.
Personal preferences again will set the camp you love/hate.
The can be a picky on mains too, so a quality lead helps here too.
As with all things, try the units in your own system against something you have as a known quantity.

anthonyTD
20-04-2008, 10:49
The only way to make a switching amplifier work properly (IMHO) is to use the module as an output stage, and creat a fully discrete front end. (or design your own!)
Some modules used on chip fets, these produced some cracking results and with reasonable power (80W rms) at 0.001% THD.
Some are dry ( most mass produced units) and can be clinical too.
This is no small part to the power supply, imho a linear PSU is far more sonically preferable to smps. We have own own transformers custom built for the specific application. More to it than just a psu I would agree, (however as with anything that works, proper design/lay-out,testing and component selection pays dividends)
Switching amps can be pretty special, as quality SS are (Dartzel). Never been that struck on all class 'a' designs (Pass labs X350/600 owner too) they do certain things very well again, yet far short in the total coherence states.
Personal preferences again will set the camp you love/hate.
The can be a picky on mains too, so a quality lead helps here too.
As with all things, try the units in your own system against something you have as a known quantity.

mr C,
there is definately something in that, imho the main problems i have heard are down to the front end, but you do need to use as bigger PSU as is physicaly posible to get the best from them, although this may seem to some to defeat the object of using eficient class D technology in the first place!
anthony...;):)

Ashley James
20-04-2008, 11:06
Dave Alner who used to build AVI and had a hand in the design of our now finished Lab Series Integrated, "designed" and built the Veritas Amp using a Tri-Path Module. I don't know why but they were very unreliable.

Martin doesn't like Class D and www.ls-design.co.uk who are a design consultancy and manufacturer (they make our electronics but we design them) have considerable experience of them and don't like them either. Naim are using 10 International Rectifier Class D modules in their contribution to the Bentley Radio.

We had an approach from Sequoia Technologies (Crystal Semiconductors) to demonstrate one of the latest and best Class D Chipsets and we decided to hear it. It sounded quite good but with a hint of the hashiness that comes with crappy CD players. The power supplies are also quite complex to implement as all the rails must come up at different times and if they don't nasties occur, which is why we decided they were no use to us. They were going to cost more than two far better analogue amplifiers. However there are plenty of hi fi amps that sound worse than Class D and get unjustified, good reviews, so it isn't surprising that people like them.

The problems in them that Martin describes are: Jitter, noise, out of band hash, varying output impedance which sabotages the perceived power output at lower frequencies. He is of the opinion that they've probably been developed as far as they are likely to be and that they are not suitable for very high quality high power sound reproduction. But since most British hi fi manufacturers aren't making powerful enough linear amplifiers for the dynamic range of modern recordings, it may well be that they see this as a cheaper way to get the extra power they need without having to pay premium prices for Copper and Aluminium. The Chinese take the Lion's share.

Mr. C
20-04-2008, 11:25
Anthony,

I would agree whole-heartily with the quality psu sentiment, we have some deigns, which produce a mere 120Wrms, yet can switch at 25n/s, ultra-quiet, yet supremely musical, fluid, and involving and generate serious amps of current, run little more then tepid in temperature.
They do require top spec cores, balanced design, we use 2 tx's, tie the '0' volts together and use each tx as separate '=' and '-' supply rails. This along with some special bridges and purposely designed smoothing caps makes for 'proper performance'

Ashely,

For every one who dislikes a product another one with make it work :-)
I cite a recent event that happened at an quality emporium, not too far from your good-selves close to 2 weeks ago. Were a gentleman went to audition a pre-power combination from yourselves, against a integrated class 'd' amplifier.
Consequently the owner of the emporium was so taken with the product (it had shown the door to the combo, comprehensively he was auditioning) he wanted the gentlemen to leave the product there! A true happening Ashely.
Perhaps there is no accounting for taste possibly!

Nick
20-04-2008, 13:14
I also had the RedWine Audio Sig 30.2 Now these baby’s really are special. I have to say very valve like in sound and presentation. A nameless person didn't actually realise he was listening to the RedWine amp rather than my normal Almarro 50125. One big advantage of the RedWine is they are Battery Powered and are disconnected from the mains during use. Therefore no mains to bugger up the sound.
Andy - SDDW

I would echo the comments on the RWA 30.2 a bona fide over achiever.

Nick

Ashley James
20-04-2008, 13:18
Mr C. At the risk of starting another fight I'd disagree, I don't see that choosing one device over another on the day as proving anything, because it's my experience customers often realise later that they've made a mistake. To my mind, if something measures right it is right and if it doesn't it isn't and people invariably eventually realise.

I'll cite an example. Some years ago we put a CD player into What Hi Fi for review, and as you know we design these things using the DAC manufacturers evaluation boards to make absolutely certain that ours sounds and measure the same, or that we've followed their instructions. There's no other way to do it, except wrong. Therefore we knew it was right and should do as well as the best. In the event it was described as: "Sweet sounding, laid back and more detailed than the others in the groups, but lacking their hard edge attack and excitement". In other words, ours was right and the rest were wrong and the reviewer had made a serious mistake. Needless to say a very good selling CD player stopped selling and we got numerous calls and complaints from people with a complete AVI system who substituted a five star CD player for ours and didn't like the harshness. They rather illogically assumed the amp's sound had changed and were reluctant to believe What hi fi could make a mistake.

It is for this reason that I've appeared on various message boards, not so much to sell AVI above all else, which I don't think would work for reasons discussed, but to counter dealers who argue that it's all lovely and that you must choose what's right for you. Bollocks and double Bollocks! say I, you're better offer armed with knowledge that helps you to understand the hearing process and that helps you select something that you can live with in the long term. Dealers need to stock and support a wide range of products and magazines need to sell magazines. We'd like you to buy AVI, but would still be happy if by using better methods to help the decision making process you buy something else that does the trick.

Ash

PS and this will cause grief - ADM9s have the highest customer satisfaction rate that we've ever seen, it might be 100%!!!! As you know, we've a strong following but this amounts to more.

jcbrum
20-04-2008, 13:22
I dunno about "tastes", some people are too "naive" (nice word for ignorant, due to insufficient education) to recognize a good thing when they see it.

Class D, is an old valve amp technology, which was in use primarily to provide servo amplifiers in control systems. It fell out of use about 40 years ago when digital techniques became popular, and solid state devices being smaller and more powerful took over.

Class D, just means it's a pulse width modulated amplifying device. It requires a high frequency oscillator approximating to a square wave which chucks out prodigious quantities of hash at all sorts of frequencies, which then has to be filtered out at the outpuy stages. Because of all this filtration and the inductive nature of loudspeakers, the damping factor or "grip" of the class d amp is poor.

You can't polish a class D amp, or not much anyway.

BTW Class D just means pulse width modulated, due to the bias state of the amplifying stages. It is nothing to do with digital amplifiers.

I'll return to being a grump old sod shall I ? ;)

jcbrum
20-04-2008, 13:26
BTW for those who remember them, "Sinclair" "Radionics" used to sell 50watt amps that cost about £4-19-11d for DIY'ers to put in their own cases. They were class D. :smoking:

Marco
20-04-2008, 13:30
Indeed. Pure Class A is where it's at, especially when the circuit is used in conjunction lovely glowing bottles... ;)

Ashley,


To my mind, if something measures right it is right and if it doesn't it isn't and people invariably eventually realise.


Oh how I vehemently disagree with that!!

But I don't have the energy to argue with you today, after a long drive home late early this morning. I'm sure others will fill in for me, though.

Marco.

jcbrum
20-04-2008, 13:43
Class A is indeed very good, but impractical except at low power, this cause amplifiers to be designed with "acceptable soft clipping" which of course leads to considerable distortion and produces "musicality" amd "involvement" which many people like.

In modern ss designs this type of distortion is often re-introduced as "valve sound" or "British Eq".

There is nothing wrong with class A as long as you don't need more than about 0.5 watts with 10 watt peaks.

It's very suitable for a headphone amp but not much else. :)

Marco
20-04-2008, 13:46
Hahahaha...quite. As they say in Scotland, JC, 'Yer heid's full of broken bottles' ;)

Marco.

jcbrum
20-04-2008, 15:23
http://www.nvg.org/sinclair/audio/gallery/x-10_ad.jpg

After the lapse in time some of us can look fondly on this advertisement.

However at the time "Wireless World" refused to carry the advertisement as the advertising standards people said it was "not capable of being substantiated"

Some things in hifi never change .

Ashley James
20-04-2008, 15:23
Marco although it's no longer the case, Class A sounded better because it avoided crossover distortion and THEREFORE MEASURED BETTER. However, that's no longer the case and it now has no advantages only disadvantages. You just cannot get enough power out of one for modern recordings and clipping Class A is just as nasty as clipping Class B.

Measurements tell a good engineer everything and the rest of the world very little and therein lies the problem.

Ashley James
20-04-2008, 15:28
Mr Sinclair's amplifier designs have lasted to this day in British Hi Fi (mentioning no names) but not his digital one.

I see that he's correctly claiming that there is no loss of power at higher frequencies to 20kHz, which was/is a valve issue.

Ash

Marco
20-04-2008, 17:03
Ashley,

But you see the difference is I'm not a manufacturer making equipment for the masses, like you, with the inevitable constraints in various areas that brings. I'm an enthusiast optimising his system for best results in a domestic environment. I don't require to think like a manufacturer or engineer, and comply to certain 'standards & regulations' which aren't necessarily sympathetic to my goals (the most musical sound possible from my hi-fi system) or the goals of people like me who share my values with audio.

Therefore I couldn't give a donkey's bollocks what MEASURES BETTER. The fact that you say Class A is worse and yet I run a Class A valve amp which my ears tell me offers superior performance to the solid state monoblocks they replaced proves that measurements only tell you part of the story. They are not the 'be-all-and-end-all' in hi-fi, like you make out.

Interestingly the selection of D.I.Y single-ended triode valve amps I heard yesterday, designed by very capable people, produced a quite superb sound with high-efficiency speakers in areas that no solid state amp could ever hope of reproducing. I suspect they would measure terribly, but they sounded wonderful, and that's all that matters. The human ear is a complex thing that science when applied to audio will probably never fully understand.

My motto with hi-fi? Trust your ears (if they're good, and mine are), not an oscilloscope. Have faith in your hearing acuity and worry not. If it sounds better then it *is* better. Manufacturers can't do this, though ;)

Marco.

jcbrum
20-04-2008, 17:39
The human ear is a complex thing that science when applied to audio will probably never fully understand.
Marco.

I think it's the bit in between that matters :)

Marco
20-04-2008, 17:42
I absolutlely agree, and my bit says valves and Class A sound better despite not measuring better :)

Marco.

Mike
20-04-2008, 17:45
i
and produces "musicality" and "involvement" which many people like.

And surely that is the most important thing with a HiFi system? That it's owner "likes" what it does, no?


and yet I run a Class A valve amp which my ears tell me offers superior performance

Fair enough!...... Hmmm, but I wouldn't be so sure that yours runs 'purely' in class A Marco, I think it pumps out a bit too much power for that, could be wrong though. Probably doesn't matter, it will no doubt at least be substantially operating in class A and how often do you whack the volume all the way up anyway?

Like you say, if it sounds right and you enjoy it, that's all that matters! :)

Cheers,
Mike.

Sand Dancin Donkey Walker
20-04-2008, 17:49
Marco a reply re- your question;

"Therefore I couldn't give a donkey's bollocks what MEASURES BETTER"

About 2" Diameter and don't taste very nice - Pleae don't ask how I know this

Andy - SDDW

Mike
20-04-2008, 17:50
Something to do with Spanish sausages maybe?

jcbrum
20-04-2008, 17:57
I think they taste nice ! Spanish Sausages that is, I thought it was the Italian ones that had the spherical objects in 'em.






At least that would explain some of Marco's opinions ! :lol: :ner:





JC.

Mr. C
20-04-2008, 18:01
JC,

Forever the wind up artist, still in-search of the eternal place to rest your ever ever increasing ego-gathering device :ner:
Would love to meet up this week Jc?, you are only a mere 40 minutes from ourselves, I would be greatfull for you to show me how good you ad9's are.
I am prepared to be enlightened in a home enviroment Jc
Guys
Personally I have only ever heard 2 Class "a" amplifiers that sounded 'acceptable' one valve, the other solid state, the rest are just pale approximations of amplifiers imho.
I also believe your amp Marco genuinely does not produce 60watts of Class 'a', to so you would need another amplifier of the same size for the other channel as they would be mono blocks :)
This is jolly fun thread chaps :smoking:

Mike
20-04-2008, 18:35
I also believe your amp Marco genuinely does not produce 60watts of Class 'a', to so you would need another amplifier of the same size for the other channel as they would be mono blocks :)
This is jolly fun thread chaps :smoking:

Hi Mr C

It's not just me then, who thinks 60W per channel is, er, 'pushing the envelope' for a pair of KT88's per side in class A?

;)

jcbrum
20-04-2008, 19:02
2xkt88 used to do 30 watts AB and 40 watts B when I was a lad. From memory a kt88 does about 5 watts class A.

Perhaps they've grown in the last 50 years, or is Marco measuring the watts with his ears.

If his valve amp was doing 60w class A, then the anode loads would draw about 600w and another 150w for other things would mean the thing was glowing like a barbecue and would probably melt.

BUT, let us not forget that for Marco measurements are irrelevant and his ears are everything that matters.

I think we should allow him to investigate the matter further if he wishes, or not as he pleases.

Illegitami non carborundum, Marco ! ;):)

jcbrum
20-04-2008, 19:27
JC,

Forever the wind up artist, still in-search of the eternal place to rest your ever ever increasing ego-gathering device :ner:
Would love to meet up this week Jc?, you are only a mere 40 minutes from ourselves, I would be greatfull for you to show me how good you ad9's are.
I am prepared to be enlightened in a home enviroment Jc

This is jolly fun thread chaps :smoking:

You're a dealer Mr C, just order a pair, I'll show you how a MacBook works if you wish.

Weren't you telling us all about the expensive posh digital music server systems you had for sale recently. :);)

anthonyTD
20-04-2008, 19:31
2xkt88 used to do 30 watts AB and 40 watts B when I was a lad. From memory a kt88 does about 5 watts class A.

Perhaps they've grown in the last 50 years, or is Marco measuring the watts with his ears.

If his valve amp was doing 60w class A, then the anode loads would draw about 600w and another 150w for other things would mean the thing was glowing like a barbecue and would probably melt.

BUT, let us not forget that for Marco measurements are irrelevant and his ears are everything that matters.

I think we should allow him to investigate the matter further if he wishes, or not as he pleases.

Illegitami non carborundum, Marco ! ;):)

marco's amp is not a true class A AMP, but it is at about 30 watts.
but he has heard what a true 60 watt class A ALL valve amp can do at my house!
a kt88 has an anode dissipation of 35 watts, it's a tetrode, so in theory you should be able to get around 60% of that in class A.
IF IT WERE A TRIODE it would be down to about 20%.
it is quite posible to get 30 watts out of a pair in true class A.
but you need a good power supply...
ash, i think the switching distortion of class B amps is a lot more objectionable than anything a good class A AMP could ever do.
anthony...;):eyebrows:

anthonyTD
20-04-2008, 19:41
marco's amp is not a true class A AMP, but it is at about 30 watts.
but he has heard what a true 60 watt class A ALL valve amp can do at my house!
a kt88 has an anode disapation of 35 ,watts, its a tetrode, so in theory you should be able to get around 60% of that in class A.
IF IT WERE A TRIODE it would be down to about 20%.
it is quite posible to get 30 watts out of a pair in true class A.
but you need a good power supply...
ash, i think the switching distortion of class B amps is a lot more objectionable than anything a good class A AMP could ever do.
anthony...;):eyebrows:
i will eloborate further,
a true class A AMPLIFIER should draw the same amount of current at all times whether it's sitting idle, or being driven flat out,[MOST SINGLE-ENDED AMPLIFIERS ARE INHERENTLY CLASS A] if it draws a different amount of current at any part of its modulation amplitude, its not true class A!
THIS IS WHY CLASS A AMPLIFIERS RUN VERY WARM, ARE VERY INEFFICIENT USE LOADS OF WATTAGE, BUT SOUND GLORIOUS!!!:eyebrows::eyebrows::eyebrows::eyebrows :;):)

Marco
20-04-2008, 19:43
Anthony's just answered the question :)

The W.P.C figure doesn't worry me, and yes for that you do need some measuring equipment (it comes in handy now and then, I guess ;)).

So in summary it's probably Class A at the levels I listen at when on my own, but when 'the lads' come round for a sesh, it won't be full Class A at the levels we listen at then :fingers:

What must be remembered is that a) my listening room is small (but perfectly formed!) b) the SP100s are an easy 8ohms load with 90db efficiency, and the Yaqin drives them comfortably with no strain whatsoever to deafening levels in my room. There is honestly no perceived drop in overall loudness with music compared to the ECS 200W monoblocks, and I get all the subtlety, tonal colour, and huge dynamic range of valves, too!

Tony,

I can't believe that you don't like the Sugden A21a Class A amp. To me it's very musical sounding indeed, providing it's partnered synergistically.

Marco.

anthonyTD
20-04-2008, 20:14
Anthony's just answered the question :)

The W.P.C figure doesn't worry me, and yes for that you do need some measuring equipment (it comes in handy now and then, I guess ;)).

So in summary it's probably Class A at the levels I listen at when on my own, but when 'the lads' come round for a sesh, it won't be full Class A at the levels we listen at :fingers:

What must be remembered is that a) my listening room is small (but perfectly formed!) b) the SP100s are an easy 8ohms load with 90db efficiency, and the Yaqin drives them comfortably with no strain whatsoever to deafening levels in my room. There is honestly no perceived drop in overall loudness with music compared to the ECS 200W monoblocks, and I get all the subtlety, tonal colour, and huge dynamic range of valves, too!

Tony,

I can't believe that you don't like the Sugden A21a Class A amp. To me it's very musical sounding indeed, providing it's partnered synergistically.

Marco.

I WILL ELABORATE EVEN FURTHER!
[I AM ON A ROLE]
the power supply is very important in class A amplifiers, but it's even more important in switching designs, switching meaning the output devices needing to draw different amounts of current according to the changes in amplitude of the music. The main problem is the slew rate of the devices used to do the switching, and the speed potential of the power supply to supply the current needed to reproduce the sometimes ferocious transients of some types of music! In other words, if the output devices cannot switch fast enough to react to the demand of the transients, then those transients never get reproduced with the same amplitude as the original. Also, if the power supply doesn't have the necessary current capability in reserve for when it's needed it will cause the same result.
with a class A design, the devices are drawing the maximum current, ALL the time, they dont have to go searching for it when a transient comes along, therefore, they reproduce it with ease!!!;):):eyebrows:;)

Marco
20-04-2008, 20:27
Which is probably a technical explanation for why I find them so musical sounding; more so than other types of amplifier circuit :)

You see, JC, that's why I don't need measuring apparatus to determine differences in hi-fi equipment. My ears get it right 95% of the time, and there's usually a technical explanation available to back up what I hear, subjectively ;)

Read and weep, science boy! :lolsign:

Marco.

jcbrum
20-04-2008, 20:31
a true class A AMPLIFIER should draw the same amount of current at all times whether it's sitting idle, or being driven flat out,[MOST SINGLE-ENDED AMPLIFIERS ARE INHERENTLY CLASS A] if it draws a different amount of current at any part of its modulation amplitude, its not true class A!
THIS IS WHY CLASS A AMPLIFIERS RUN VERY WARM, ARE VERY INEFFICIENT USE LOADS OF WATTAGE, BUT SOUND GLORIOUS

This is only partly true and is not a "real world" situation.

I'm not criticizing your explanation Ant, but I think it's worth being "nit picking" in this case. :)

A true class A amp is merely one where sufficient grid bias is applied to prevent any grid current flowing at all with the chosen anode potential applied to the anode load. Then by applying a signal to the grid, the anode current will be modulated and an analogue of the grid signal will appear across the anode load. It will have a higher potential swing and therefore be "amplified". The maximum amplification occurs when the maximum anode voltage is applied across the maximum anode load in series with the valve.

That is why a "text- book" explanation is not applicable to the real world. The amplifier would be too unreliable because of things like humidity, ambient temperature, and ageing of components. About 50%-60% of max was a common real world objective with a conservative design employing considerably less than that.

It is also possible that my earlier recollections applied to KT66's rather than KT88's.

Hope this is of some interest. :)

jcbrum
20-04-2008, 20:42
Bin there, done it Marco, 1962.

I bet you even missed out on the 1966 world cup :doh:

LOOZEERRRRRRR :lolsign:


(just kidding):)

(mostly):lol:

JC.
:cool:

anthonyTD
20-04-2008, 20:43
This is only partly true and is not a "real world" situation.

I'm not criticizing your explanation Ant, but I think it's worth being "nit picking" in this case. :)

A true class A amp is merely one where sufficient grid bias is applied to prevent any grid current flowing at all with the chosen anode potential applied to the anode load. Then by applying a signal to the grid, the anode current will be modulated and an analogue of the grid signal will appear across the anode load. It will have a higher potential swing and therefore be "amplified". The maximum amplification occurs when the maximum anode voltage is applied across the maximum anode load in series with the valve.

That is why a "text- book" explanation is not applicable to the real world. The amplifier would be too unreliable because of things like humidity, ambient temperature, and ageing of components. About 50%-60% of max was a common real world objective with a conservative design employing considerably less than that.

It is also possible that my earlier recollections applied to KT66's rather than KT88's.

Hope this is of some interest. :)

i tried to simplify it because i didnt want bore people, but your right, i should have gone the long winded aproach to get my point over to the more technicaly minded, but my point is still valid, you cannot get maximum voltage amplitude without the necesary current being available in the first place!!! :);)

Marco
20-04-2008, 20:46
That is why a "text- book" explanation is not applicable to the real world.


That's exactly what I think when Ashley and you quote measurements to back up your assertions with computer audio, transports and DACs, amplifiers, etc!! :lol:

Anyway, incidentally, how many watts of Class A do the ADM9s have, and how big is the mains transformers used? After all it does (according to Ash) reproduce 200-Watt transients... ;)

Marco.

jcbrum
20-04-2008, 20:47
We're agreed then.

Maybe Marco's amp will catch fire again while he's not looking.

He gone awfully quiet.

Marco
20-04-2008, 20:49
Bin there, done it Marco, 1962.

I bet you even missed out on the 1966 world cup :doh:

LOOZEERRRRRRR :lolsign:


(just kidding):)

(mostly):lol:

JC.
:cool:


I was one year old in 1966 - so thank f*ck I missed all that crap. Mind you it doesn't stop the English mentioning 1966 every five minutes still to this day :lol:

;)

Marco.

jcbrum
20-04-2008, 20:50
UH-UH, spoke too soon.

Marco
20-04-2008, 20:53
We're agreed then.

Maybe Marco's amp will catch fire again while he's not looking.

He gone awfully quiet.


Quiet? WTF are you on about? :scratch:

I'm all over this thread like a rash!

There's no chance of anything like that happening again - and Anthony will be fitting new Sowter mains and output transformers to it soon, so you can kiss goodbye to that notion, shweety :eyebrows:

Marco.

P.S you haven't answered my question. Get it answered toute-suite!!

anthonyTD
20-04-2008, 20:57
We're agreed then.

Maybe Marco's amp will catch fire again while he's not looking.

He gone awfully quiet.

AS CELINE DION DECLARED, MY HEART WILL GO ON,
I am confident that marco's amp will now go on, and on, and on........:eyebrows:;):)

lurcher
20-04-2008, 20:59
A true class A amp is merely one where sufficient grid bias is applied to prevent any grid current flowing at all with the chosen anode potential applied to the anode load. Then by applying a signal to the grid, the anode current will be modulated and an analogue of the grid signal will appear across the anode load. It will have a higher potential swing and therefore be "amplified". The maximum amplification occurs when the maximum anode voltage is applied across the maximum anode load in series with the valve.



Err, no,

A class A amp is one where the output device(s) are conducting for the entire signal cycle (360deg)

A class B amp is one in which the output device(s) conduct over a angle of 180 deg or more and less than 360

A class C amp is one in which the output device(s) conduct less than 180 deg of the cycle.

Grid current is nother to do with the class of the output deviceA,B or C. An A1 stage is one which no grid current flows during the cycle. A A2 amp is one where grid current flows from more than zero to 360deg of the cycle. And there can be B2 and C2 variations where grid current flows during part or all of the cycle.

The 211 amp of mine that Marco heard over the weekend is biased such that grid current flows at about 10w, then all the way to 32w. So its a A2 amp, the single output device conducting all the time.

BTW, grid current starts to flow before the 0v line, and will also flow with high gm frame grid valves like the ECC88 before the official 0v grid line,

jcbrum
20-04-2008, 20:59
Dunno wot your on about ? question ?

Marco
20-04-2008, 21:00
Like Ariston...and ON AND ON AND ON AND ON...

Like the 'AVI boys' going on about ADM9s, and ON AND ON AND ON AND ON AND ON ON AND ON AND ON AND ON AND ON ON AND ON AND ON AND ON AND ON ON AND ON AND ON AND ON AND ON ON AND ON AND ON AND ON AND ON, unitl infinity...!

:ner:

Marco.

Marco
20-04-2008, 21:02
Dunno wot your on about ? question ?

Keep up for goodness sake!! ;)

This one:

Anyway, incidentally, how many watts of Class A do the ADM9s have, and how big is the mains transformers used? After all it does (according to Ash) reproduce 200-Watt transients...

Waiting patiently...

Marco.

anthonyTD
20-04-2008, 21:04
Err, no,

A class A amp is one where the output device(s) are conducting for the entire signal cycle (360deg)

A class B amp is one in which the output device(s) conduct over a angle of 180 deg or more and less than 360

A class C amp is one in which the output device(s) conduct less than 180 deg of the cycle.

Grid current is nother to do with the class of the output deviceA,B or C. An A1 stage is one which no grid current flows during the cycle. A A2 amp is one where grid current flows from more than zero to 360deg of the cycle. And there can be B2 and C2 variations where grid current flows during part or all of the cycle.

The 211 amp of mine that Marco heard over the weekend is biased such that grid current flows at about 10w, then all the way to 32w. So its a A2 amp, the single output device conducting all the time.

BTW, grid current starts to flow before the 0v line, and will also flow with high gm frame grid valves like the ECC88 before the official 0v grid line,

whey hey,
spoken like a true class A gent, welcome aboard that man!!!:);):eyebrows::lol:

Marco
20-04-2008, 21:07
JC's out of his depth here, mate.

Between Nick (Lurcher) and you there's probably more technical hi-fi knowledge here than his little brain can safely handle without going POP! :eyebrows:

Marco.

jcbrum
20-04-2008, 21:10
Err, no,

A class A amp is one where the output device(s) are conducting for the entire signal cycle (360deg)

A class B amp is one in which the output device(s) conduct over a angle of 180 deg or more and less than 360

A class C amp is one in which the output device(s) conduct less than 180 deg of the cycle.

Grid current is nother to do with the class of the output deviceA,B or C. An A1 stage is one which no grid current flows during the cycle. A A2 amp is one where grid current flows from more than zero to 360deg of the cycle. And there can be B2 and C2 variations where grid current flows during part or all of the cycle.

The 211 amp of mine that Marco heard over the weekend is biased such that grid current flows at about 10w, then all the way to 32w. So its a A2 amp, the single output device conducting all the time.

BTW, grid current starts to flow before the 0v line, and will also flow with high gm frame grid valves like the ECC88 before the official 0v grid line,

Er yes. Grid Potential and therefore current is how you control the conduction angle with a given max peak to peak grid modulation.

Stop being even more picky than me. You'll confuse Marco and we'll never hear the last of this bloody valve junk. :mental:

If your amp draws grid current at 10w then in my book it ain't true class A. But thats because a KT66 ain't a triode and the screen grid is helping the anode isolation.

If you want a proper class A amp then you need to use triodes.

Lets not go there.:)

JC:)

anthonyTD
20-04-2008, 21:14
Er yes. Grid Potential and therefore current is how you control the conduction angle with a given max peak to peak grid modulation.

Stop being even more picky than me. You'll confuse Marco and we'll never hear the last of this bloody valve junk. :mental:

If your amp draws grid current at 10w then in my book it ain't true class A. But thats because a KT66 ain't a triode and the screen grid is helping the anode isolation.

If you want a proper class A amp then you need to use triodes.

Lets not go there.:)

JC:)

if you connect the screen grid to the anode of a kt66, then its a true triode!!!
and a very linear one at that...:);):eyebrows:

anthonyTD
20-04-2008, 21:20
Keep up for goodness sake!! ;)

This one:

Anyway, incidentally, how many watts of Class A do the ADM9s have, and how big is the mains transformers used? After all it does (according to Ash) reproduce 200-Watt transients...

Waiting patiently...

Marco.
BLOODY HELL! [SORRY] THATS AN INTERESTING QUESTION MARCO [HE HE]
cant wait for the answer, its gonna be good...........;):eyebrows:

lurcher
20-04-2008, 21:25
If your amp draws grid current at 10w then in my book it ain't true class A. But thats because a KT66 ain't a triode and the screen grid is helping the anode isolation.

If you want a proper class A amp then you need to use triodes.


Well, clearly your book has a different definition to the rest of the world, at least the rest of the world that studies electronic engineering, thats fine, but it doesn't make it any more true.

I wasn't commenting about the kt88 amp, just about the misuse of definitions and the attempt to introduce some sort of notion about "pure" class A. As pointed out, the screen grid will only function as such if its connected to a fixed (WRT the cathode) potential, connecting it to the anode (via a limiting resistor to stay within the g2 current limits) makes it a perfectly good triode. There are issue of partition noise with the extra grids, but the kt88 makes a perfectly good indirectly heated triode. Its not perfect as it still suffers from the island effect.

And you might have noticed the example I gave of A2 was using a 211, which certainly hasn't any extra grids in there, and if you take a look at the curves is of course designed for grid current.

Marco
20-04-2008, 21:26
Yes, he still hasn't answerd yet, and I won't ask again!!!

JC?????

Marco.

jcbrum
20-04-2008, 21:36
Sorry, I was watching telly, They say John Prescott has Bulimia !

Err, why not ask Ash, or have a look at the website, I think it gives the figures,

They're bloody LOUD, I can tell you that. :smoking:

anthonyTD
20-04-2008, 21:38
Sorry, I was watching telly, They say John Prescott has Bulimia !

Err, why not ask Ash, or have a look at the website, I think it gives the figures,

They're bloody LOUD, I can tell you that. :smoking:
so is a ten watt class A valve amp!!!;)

jcbrum
20-04-2008, 21:45
Nah, only if you use joke speakers.
The website says 350 watts per channel, but I think that was the usb version. I think the current optical version is 325 watts per channel.

Marco
20-04-2008, 21:50
I heard a few "joke" speakers yesterday, but the funny thing was they weren't much of a joke...

Marco.

anthonyTD
20-04-2008, 21:52
Nah, only if you use joke speakers.
The website says 350 watts per channel, but I think that was the usb version. I think the current optical version is 325 watts per channel.

NOT A GOOD ENOUGH ANSWER jc,
HOW MANY OF THOSE WATTS ARE CLASS A?
and there's nothing wrong with efficient speakers, one of the main reasons amplifier power started going up from the 70s onwards was one, because they could, [transistors being cheaper than valves] and two, because it was cheaper to do this than to carry on making good efficient speakers.:);)

jcbrum
20-04-2008, 21:53
Well, clearly your book has a different definition to the rest of the world, at least the rest of the world that studies electronic engineering, thats fine, but it doesn't make it any more true.

I wasn't commenting about the kt88 amp, just about the misuse of definitions and the attempt to introduce some sort of notion about "pure" class A. As pointed out, the screen grid will only function as such if its connected to a fixed (WRT the cathode) potential, connecting it to the anode (via a limiting resistor to stay within the g2 current limits) makes it a perfectly good triode. There are issue of partition noise with the extra grids, but the kt88 makes a perfectly good indirectly heated triode. Its not perfect as it still suffers from the island effect.

And you might have noticed the example I gave of A2 was using a 211, which certainly hasn't any extra grids in there, and if you take a look at the curves is of course designed for grid current.


Yeah, yeah, A2 ain't "A", it's A2.

It doesn't work connecting the screen and anode together, I agree you get a perfectly usable triode, but it buggers the usable dissipation figures and the screen seriously overheats on high power.

Much better to design a tetrode or pentode amp.

Ive always wanted to try a triode connected 4cx350, do you know whether anyone has ever tried it ? I've still got the valves and bases, and the 20A heater transformers and 2Kv HT transformers in the garage somewhere.

I used to run them at 2 KiloWatts class C in 1972, but they were f'-ing lethal and used to turn the air blue inside the cabs.

anthonyTD
20-04-2008, 22:03
Yeah, yeah, A2 ain't "A", it's A2.

It doesn't work connecting the screen and anode together, I agree you get a perfectly usable triode, but it buggers the usable dissipation figures and the screen seriously overheats on high power.

Much better to design a tetrode or pentode amp.

Ive always wanted to try a triode connected 4cx350, do you know whether anyone has ever tried it ? I've still got the valves and bases, and the 20A heater transformers and 2Kv HT transformers in the garage somewhere.

I used to run them at 2 KiloWatts class C in 1972, but they were f'-ing lethal and used to turn the air blue inside the cabs.

JC,
i agree, and thats why i only use KT88's AS TETRODES, i was just stating a fact as far as the triode thing is concerned [you brought it up mate !] and if you use a resistor between the anode and screen grid [100 ohm?] the screen grid is safe!!!:);)

jcbrum
20-04-2008, 22:04
one of the main reason amplifier powers started going up from the 70's on was one, because they could, [transistors being cheaper than valves] and two, because it was cheaper to do this than to carry on making good efficient speakers.:);)

Nothing to do with making better loudspeakers, like ESL57's and BC1's then ? :)

and what planet are you from. ? Puny amps clip. Clipping puts a DC current through your voice coils and smokes your speakers. :(

About 100watts rms per channel at full drive is minimum for a satisfactory clipping performance at fairly quiet listening levels. Some say much more is better. :smoking:

I think you need an amp with 40-50db of gain, and thats quite hard to do with valves on a continuous duty cycle.:)

jcbrum
20-04-2008, 22:08
You don't seem too bad on your valve theory Ant and Lurcher, but you really should try AVI's power amps. They are really nicely designed by Martin. He's very good at it. You should meet him one day. :)

anthonyTD
20-04-2008, 22:10
Nothing to do with making better loudspeakers, like ESL57's and BC1's then ? :)

and what planet are you from. ? Puny amps clip. Clipping puts a DC current through your voice coils and smokes your speakers. :(

About 100watts rms per channel at full drive is minimum for a satisfactory clipping performance at fairly quiet listening levels. Some say much more is better. :smoking:

I think you need an amp with 40-50db of gain, and thats quite hard to do with valves on a continuous duty cycle.:)
jc,
once again,
you read my posts but you dont READ my posts, i said it was cheaper to make big powerfull amps than to make good efficient speakers,i didnt say anything about making good in-eficient, expensive speakers...;):)

jcbrum
20-04-2008, 22:21
jc,
once again,
you read my posts but you dont READ my posts, i said it was cheaper to make big powerfull amps than to make good efficient speakers,i didnt say anything about making good in-eficient, expensive speakers...;):)

You mean speakers like this :

http://www.puriteaudio.co.uk/sitebuildercontent/sitebuilderpictures/P8026541.JPG


I DO read your posts, thats what I mean by "joke speakers".:) (sorry Coops)


I'd rather have speakers like this :


http://www.avihifi.com/avid/ADM9-rosewood-TV.jpg


They say a picture is worth a thousand words, but the first one leaves me speechless ! ;)

jcbrum
20-04-2008, 22:24
Ooops help, Filterlab can you resize that ?

anthonyTD
20-04-2008, 22:27
You mean speakers like this :

http://www.puriteaudio.co.uk/sitebuildercontent/sitebuilderpictures/P8026541.JPG


I DO read your posts, thats what I mean by "joke speakers".:) (sorry Coops)


I'd rather have speakers like this :


http://www.avihifi.com/avid/ADM9-rosewood-TV.jpg


They say a picture is worth a thousand words, but the first one leaves me speechless ! ;)

nice system !
dont think much of that AV set up though!
come on jc, get back to answering the questions in hand, and stop trying to steer things off in a direction that you can control..;)

Marco
20-04-2008, 22:34
I'd rather have speakers like this [followed by a picture of some 'joke' speakers]
:lol:

;)

Where are they? I can hardly see them... Are they those tiny little lollipops pictured in that boring looking 'lifestyle' system? :scratch:

Marco.

P.S the Cessaro horns are lovely, and veritable works of art!

jcbrum
20-04-2008, 22:35
Dunno what you're on about :scratch: I'm off to bed soon :)

anthonyTD
20-04-2008, 22:37
Dunno what you're on about :scratch: I'm off to bed soon :)

night night!!!;):);):):)

jcbrum
20-04-2008, 22:38
Hey, stop misquoting me ! :steam: Marco


I couldn't have those silly lavatory bowl speakers in my house, visitors would laugh at me and my friends would think I'd become insane :)

Where are they manufactured ?

lurcher
20-04-2008, 23:11
Yeah, yeah, A2 ain't "A", it's A2.

It doesn't work connecting the screen and anode together, I agree you get a perfectly usable triode, but it buggers the usable dissipation figures and the screen seriously overheats on high power.

Much better to design a tetrode or pentode amp.

Ive always wanted to try a triode connected 4cx350, do you know whether anyone has ever tried it ? I've still got the valves and bases, and the 20A heater transformers and 2Kv HT transformers in the garage somewhere.

I used to run them at 2 KiloWatts class C in 1972, but they were f'-ing lethal and used to turn the air blue inside the cabs.


Yep, and there is no such thing as A, there is A1 and A2, you point being?

I did of course mention using a resistor to limit g2 diss, but hey oh, just read a bit and answer that part.

No, I haven't tried a 4cx350, I guess you were using that in C2. 212s are fun for audio use though, but a tad low on the "usable in the home" scale. I do mean to try using a pair of the eimac multi anode valves some time for audio when I get round to it :-).

Shame about the idiot box between those two speakers, I would have thought that the placement that close together in a corner with the window to one side would have compromised things though?

We are all after different things though, for me a triode ticking over into a pair of open baffles does the trick, but thankfully we are all different.

SamJones
21-04-2008, 07:02
Thanks everyone for your views on Class D amps. Been running a pair of Flying Mole DAD-M100 Pro monoblocks with a Stello USB DAC and simple passive attenuator for a year now and have been well satisfied with the result. My interest started with a factory refurb TEAC Tripath I bought for 21 quid, it sounded marginally cleaner than a Quad 99 power amp I was running. I thought to myself, these switching amps seem the way to go with less energy consumption as a bonus.

Mr. C
21-04-2008, 07:25
Good Morning Jc,

I see your still sitting in the mire yet again, (its just the depth that varies I notice)
Like all products worth there salt, you would not lay out your hard fought for folding stuff on anything you had not auditioned, or in our case any products not shown to us to do what they say on the tin.
So I will ask a little more forwardly, demonstrate to me in your own home how good you feel the avi's and macbook are this week, the distance is not an issue.
Show me what you protestations on the forum are all about instead of the un-necessary male cow waste deposits you have been littering this place with.
Your avoidance techniques to answering questions directly put to you is pretty poor, you diversionary tactics too are in a similar vein.
Time to put up or shut up Jc

jcbrum
21-04-2008, 08:17
I see your still sitting in the mire yet again,

No mire here :) It must be you that's "in it" with all that unsold over-priced stock you're stuck with :( did you forget to audition it :lol:


So I will ask a little more forwardly, demonstrate to me in your own home how good you feel the avi's and macbook are this week, Show me what you protestations on the forum are all about instead of the un-necessary male cow waste deposits you have been littering this place with.


"Come into my parlour said the spider to the fly" - Hmmm, Why is it that I suspect your motives Mr C ? :lol: :ner:



Your avoidance techniques to answering questions directly put to you is pretty poor, you diversionary tactics too are in a similar vein


Oh I don't know, we've just had a pretty good discussion about amplifiers, without too much diversion.

Until your present post which is 100% thread-crapping, since the topic is class D amps.


It's pretty obvious that you have stocked the wrong stuff and are beginning to see the light. I think you should re-consider and get on the phone to Ashley, and order some kit. It could save your business :) :cool:

Mr. C
21-04-2008, 08:22
Jc,

I had hope for a better responce, but as usual the basic Jc reply.
Do you have any others in your limited section to choose from.
Thread crapping, this is one skill you do excel at with hons' lol

anthonyTD
21-04-2008, 09:19
No mire here :) It must be you that's "in it" with all that unsold over-priced stock you're stuck with :( did you forget to audition it :lol:




"Come into my parlour said the spider to the fly" - Hmmm, Why is it that I suspect your motives Mr C ? :lol: :ner:





Oh I don't know, we've just had a pretty good discussion about amplifiers, without too much diversion.

Until your present post which is 100% thread-crapping, since the topic is class D amps.


It's pretty obvious that you have stocked the wrong stuff and are beginning to see the light. I think you should re-consider and get on the phone to Ashley, and order some kit. It could save your business :) :cool:

come on jc,
thats verging on the downright nasty mate, answer the questions put to you, and give advice, not this crap mate!!!;)

Marco
21-04-2008, 09:44
Thanks everyone for your views on Class D amps. Been running a pair of Flying Mole DAD-M100 Pro monoblocks with a Stello USB DAC and simple passive attenuator for a year now and have been well satisfied with the result. My interest started with a factory refurb TEAC Tripath I bought for 21 quid, it sounded marginally cleaner than a Quad 99 power amp I was running. I thought to myself, these switching amps seem the way to go with less energy consumption as a bonus.


Hi Sam,

What are the Flying Moles like? I've read various reviews on them, largely positive, and I thought they sounded interesting. I like the look of them, too - functional yet elegant :)

Sorry about the tangential nature of the current discussion!

Marco.

anthonyTD
21-04-2008, 09:52
Thanks everyone for your views on Class D amps. Been running a pair of Flying Mole DAD-M100 Pro monoblocks with a Stello USB DAC and simple passive attenuator for a year now and have been well satisfied with the result. My interest started with a factory refurb TEAC Tripath I bought for 21 quid, it sounded marginally cleaner than a Quad 99 power amp I was running. I thought to myself, these switching amps seem the way to go with less energy consumption as a bonus.
hi sam,
despite their imperfections, i agree class D amps can sound exceptional in the right system, and IMHO more so than 90% of the conventional solid state stuff i have heard over the years i have been involved in this industry.
regards,anthony...;)

jcbrum
21-04-2008, 10:50
come on jc,
thats verging on the downright nasty mate, answer the questions put to you, and give advice, not this crap mate!!!;)

I think it's a suitable response, given the tone originating from MrC's post.

I think he's got the weird idea that he's in some position to make any valid judgements, which of course is silly.

The hierarchy, and therefore the feeding chain in hifi goes something like this.

At the top is the very knowledge and competent enthusiast engineer. He is likely to be at the leading edge of his particular flavour of hifi.

Next down is the manufacturer who cherry picks ideas from the above and develops them into a commercial product.

Bottom of the heap is the dealer, who in reality has no choice at all. He is in business purely to make money, and he HAS to sell what his customer wants to buy. If he fails to turn over his stock he makes big losses, because effectively he has bought a lemon that no one wants and he is forced to dump it at a heavy discount, whilst pretending it's good stuff, or go bust quickly.

He thinks somewhat pretentiously, that he is there to advise, but thats not so, he might pretend, but the bottom line is he has to exchange his goods (which he doesn't want) for money, (which he urgently needs).

So the answer is if he stocks what people want to buy then he doesn't need a complicated load of sales talk and possibly false claims (Russ Andrews ?).

If he doesn't he has a load of shiny junk in stock all the time at excessive prices.

I'm not singling MrC out. This is my advice to all dealers. Get real or go bust. :)

IMHO of course ;)

jcbrum
21-04-2008, 10:53
The bottom line is who needs dealers if they don't have what you want to listen to ? :)

Steve Toy
21-04-2008, 11:09
As a customer of Mr C's I can confirm that he does add a lot of value in terms of making your system sing. He also makes his own cabling which is very effective in achieving the above.

jcbrum
21-04-2008, 11:12
Err, I think Richard has just posted on this topic on a new thread. :)

Marco
21-04-2008, 11:16
Chaps, can we please keep this thread on-topic?

That means any discussion about delaers, ADM9s, etc, should be done on a separate thread, or one that relates to this subject. This thread is for Class D and other similar amplifier circuit discussions.

Thanks in advance :)

Marco.

anthonyTD
21-04-2008, 14:42
I think it's a suitable response, given the tone originating from MrC's post.

I think he's got the weird idea that he's in some position to make any valid judgements, which of course is silly.

The hierarchy, and therefore the feeding chain in hifi goes something like this.

At the top is the very knowledge and competent enthusiast engineer. He is likely to be at the leading edge of his particular flavour of hifi.

Next down is the manufacturer who cherry picks ideas from the above and develops them into a commercial product.

Bottom of the heap is the dealer, who in reality has no choice at all. He is in business purely to make money, and he HAS to sell what his customer wants to buy. If he fails to turn over his stock he makes big losses, because effectively he has bought a lemon that no one wants and he is forced to dump it at a heavy discount, whilst pretending it's good stuff, or go bust quickly.

He thinks somewhat pretentiously, that he is there to advise, but thats not so, he might pretend, but the bottom line is he has to exchange his goods (which he doesn't want) for money, (which he urgently needs).

So the answer is if he stocks what people want to buy then he doesn't need a complicated load of sales talk and possibly false claims (Russ Andrews ?).

If he doesn't he has a load of shiny junk in stock all the time at excessive prices.

I'm not singling MrC out. This is my advice to all dealers. Get real or go bust. :)

IMHO of course ;)
jc,
that maybe the case, and i see where your coming from [no, really, i do] but it's not up to people like you, or me, to dictate to the general public what they should be listening to, we can advise them, going on our own experiences, and knowledge in particular fields of expertise, but at the end of the day, it's their choice, and we have all seen what happens when you take away peoples right to choose...hence, the need for dealers....:);)

Ashley James
21-04-2008, 16:11
Anthony - I hope that you haven't concluded from anything I've said that I want to dictate what people should be listening to, because that's far from the case.

I firmly believe that this Industry and the Press have failed the man in the street by not providing him with an effective means of assessing equipment that he may be considering. Therefore I've illustrated ways in which the ear/brain combination is fooled in the hopes that people will be mindful.

The trouble is that I've also pointed out that if you use the tried and tested and proven methods that I've advocated, then there will be no differences between the sounds of cables for a start and much of what masquerades as hi fi will be discredited. It already has been to a large chunk of the population, but not it seems to Forum frequenters.

I knew I'd piss quite a few off, but I still feel it was worth saying what so many have thought for as long as I've been in hi fi.

Ash

Marco
21-04-2008, 16:20
The crucial difference is though that most of the population aren't discerning when it comes to the performance of hi-fi equipment, whereas the people here (and on other similar forums) generally are.

Marco.

anthonyTD
21-04-2008, 16:28
Anthony - I hope that you haven't concluded from anything I've said that I want to dictate what people should be listening to, because that's far from the case.

I firmly believe that this Industry and the Press have failed the man in the street by not providing him with an effective means of assessing equipment that he may be considering. Therefore I've illustrated ways in which the ear/brain combination is fooled in the hopes that people will be mindful.

The trouble is that I've also pointed out that if you use the tried and tested and proven methods that I've advocated, then there will be no differences between the sounds of cables for a start and much of what masquerades as hi fi will be discredited. It already has been to a large chunk of the population, but not it seems to Forum frequenters.

I knew I'd piss quite a few off, but I still feel it was worth saying what so many have thought for as long as I've been in hi fi.

Ash
ash,
fair comment, and of course you're quite within your rights [as i am] to advocate your views on this forum,[not dictate though] and i agree that there are dealers who are just out for getting the highest commission they can, and will in most cases lead the gullible astray if they think it's in their own best interests. i am all for getting rid of these tyrants, but without choice we are all doomed.
anthony...;)

leo
21-04-2008, 16:48
I've got classA , A/B and D amps.
Which is better, hard to say tbh, they all have strengths and weaknesses

You get a wide range of crap available no matter what class you choose, going by experience a lot of the crap is usually stuff thats been hyped up

anthonyTD
21-04-2008, 16:50
I've got classA , A/B and D amps.
Which is better, hard to say tbh, they all have strengths and weaknesses

You get a wide range of crap available no matter what class you choose, going by experience a lot of the crap is usually stuff thats been hyped up
I'M WITH YOU THERE LEO...;)

SamJones
21-04-2008, 23:51
Hi Sam,

What are the Flying Moles like? I've read various reviews on them, largely positive, and I thought they sounded interesting. I like the look of them, too - functional yet elegant :)

Sorry about the tangential nature of the current discussion!

Marco.

Hi Marco,

I find the Flying Mole's sound is closer to the valve amp side than solid state. Silky smooth but the fine detail extracted by the Stello DAC still comes though unhindered. What I like most about them is their ability to pump out music for long periods of time without causing ear fatigue. I find the sound quality of many class AB amps are fine initially but appear to shift to the raucous side after extended listening periods. That's the proof of the pudding for me, how the kit sounds after a few hours continuous listening. It's as if the brain tries hard to block something out, then gives up :)

anthonyTD
22-04-2008, 09:49
Hi Marco,

I find the Flying Mole's sound is closer to the valve amp side than solid state. Silky smooth but the fine detail extracted by the Stello DAC still comes though unhindered. What I like most about them is their ability to pump out music for long periods of time without causing ear fatigue. I find the sound quality of many class AB amps are fine initially but appear to shift to the raucous side after extended listening periods. That's the proof of the pudding for me, how the kit sounds after a few hours continuous listening. It's as if the brain tries hard to block something out, then gives up :)

hi sam,
what you have described at the end of this thread is how i feel about digital recorded music to a degree, although it is my main choice of replay as i dont have many records, i find its almost like me ears/brain conbination is somehow having to compensate for what its hearing [or not] and it eventually tires me.
analoug dosent seem to do that...
anthony...;):)