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"Voiced"?

Excerpts from an interview with the late Charles Hansen (Ayre):

"It's nice that the Ayre V-3 amplifier sounds so tubelike, but why not just buy a tube amplifier?"
Charlie Hansen laughed.
"If you can put up with the high prices and maintenance of tube gear, then go for it. But most people don't want to put up with the expense or the idiosyncrasies of tubes.
"Look," Charlie continued, "great tube amps still have a little bit of midrange magic that no solid-state amp I have ever heard quite gets. But the V-3 does many things better than most tube amps do. It's more dynamic. Bass is more controlled and tuneful. There's more resolution.
"The idea is to make something great-sounding and reliable that people can afford. I personally like the sound we normally associate with tubes—relaxed, musical, lots of information, but not presented in any kind of artificial way. I think that sound is truer to the music and lets you understand what an artist is trying to convey.
"The problem is that tubes are expensive and unreliable, and it's hard to find good tubes. It's also expensive to make a tube amp, because you have to have output transformers, and good transformers are expensive."

(...)

There is no loop feedback around the output stage, just a little feedback to the driver stage, necessary to control DC. I asked Charlie how he can get away with this and still keep the output impedance suitably low—around 0.25 ohms.
"I was hoping you'd ask. It's because we use very-high-transconductance MOSFETs, which were developed, actually, for low-loss switching in electric cars. The higher the transconductance, the lower your output impedance." The amp uses two pairs of these high-transconductance MOSFETs per channel—this being a balanced design, each pair of devices is carefully matched, as indeed are other parts in the signal path.

https://www.stereophile.com/content/ayre-acoustics-v-3-power-amplifier-sam-tellig-comments
 
tuga said:
So you can't make design decisions that will affect, for example, output impedance. Why is it that some amps have it high and others low?

For example, isn't there a direct correlation between Ayre's discrete zero feedback circuit design and the fact that its DACs and amplifiers always show a pinch of 2nd and 3rd order distortion?
Click to expand...

All irrelevant. As amp can be engineered to have a negative output impedance never mind high or low but it's hardly "voicing". As to why some have it high and others low well it's all down to NFB... like pretty much everything else...
Most of the time we want as low an output impedance as possible of course and the topology combined with the amount of NFB decide this. In the early 50's, mainly in USA, there was a brief trend for adjustable output impedance in valve amps in which it was set by positive feedback and could "fake" very high damping factors...
Artificially engineering in high or negative output Z for a specific speaker has been used in some active speakers and subwoofers to obtain higher order bass alignments but only works for a specific drive unit in a specific cabinet with specific port dimensions etc etc.

All amplifiers produce distortion. A zero feedback amp will produce lots more than the same amp with NFB but it can still be low ish. As was established way back, 0.1% THD or less and it can be regarded as inaudible. Higher odd orders are vastly more objectionable of course and with just 2nd then around 1% is around the audible threshold..
Interestingly, a very small amount of NFB can make things worse! It can reduce 2nd order whilst making 3rd and 5th rather higher, hence the total may fall from 5% to 2% but the amount of much more objectionable higher order distortion is increased.

However, in any amp of genuine hi fi quality it is all academic as the distortion will be low enough to be below audibility.
 
Arkless Electronics said:
All irrelevant.

However, in any amp of genuine hi fi quality it is all academic as the distortion will be low enough to be below audibility.
Click to expand...

It's not irrelevant.
Many manufacturers are designing lower or not-so-high fidelity amplifiers because they like how those designs sound and because there's a market for such equipment.
Whether you, or I, like it or not is not relevant.
 
tuga said:
Excerpts from an interview with the late Charles Hansen (Ayre):

"It's nice that the Ayre V-3 amplifier sounds so tubelike, but why not just buy a tube amplifier?"
Charlie Hansen laughed.
"If you can put up with the high prices and maintenance of tube gear, then go for it. But most people don't want to put up with the expense or the idiosyncrasies of tubes.
"Look," Charlie continued, "great tube amps still have a little bit of midrange magic that no solid-state amp I have ever heard quite gets. But the V-3 does many things better than most tube amps do. It's more dynamic. Bass is more controlled and tuneful. There's more resolution.
"The idea is to make something great-sounding and reliable that people can afford. I personally like the sound we normally associate with tubes—relaxed, musical, lots of information, but not presented in any kind of artificial way. I think that sound is truer to the music and lets you understand what an artist is trying to convey.
"The problem is that tubes are expensive and unreliable, and it's hard to find good tubes. It's also expensive to make a tube amp, because you have to have output transformers, and good transformers are expensive."

(...)

There is no loop feedback around the output stage, just a little feedback to the driver stage, necessary to control DC. I asked Charlie how he can get away with this and still keep the output impedance suitably low—around 0.25 ohms.
"I was hoping you'd ask. It's because we use very-high-transconductance MOSFETs, which were developed, actually, for low-loss switching in electric cars. The higher the transconductance, the lower your output impedance." The amp uses two pairs of these high-transconductance MOSFETs per channel—this being a balanced design, each pair of devices is carefully matched, as indeed are other parts in the signal path.

https://www.stereophile.com/content/ayre-acoustics-v-3-power-amplifier-sam-tellig-comments
Click to expand...

And? That's all bog standard stuff.... It cheats by using NFB from the drivers which means most of the amp and the all important voltage amp stage are in a feedback loop. The Densen amps do the same thing.
The most extreme and purist zero feedback (genuinely) I can think of are The Paradise phono stage and my own Arkless Transconductance one. Both manage <0.01% THD whilst amplifying around 1500x!!

Valve V SS is mainly low NFB V high NFB of course but although NFB is the most important thing in amplifier design it is of course largely ignored by the non technical... DOH!
 
Arkless Electronics said:
And? That's all bog standard stuff.... It cheats by using NFB from the drivers which means most of the amp and the all important voltage amp stage are in a feedback loop. The Densen amps do the same thing.
The most extreme and purist zero feedback (genuinely) I can think of are The Paradise phono stage and my own Arkless Transconductance one. Both manage <0.01% THD whilst amplifying around 1500x!!

Valve V SS is mainly low NFB V high NFB of course but although NFB is the most important thing in amplifier design it is of course largely ignored by the non technical... DOH!
Click to expand...

Why would anyone voice a SS to sound like Valve? Schiit, people are voicing amplifiers... :rolleyes:
 
tuga said:
It's not irrelevant.
Many manufacturers are designing lower or not-so-high fidelity amplifiers because they like how those designs sound and because there's a market for such equipment.
Whether you, or I, like it or not is not relevant.
Click to expand...

Such amplifiers are not hi fi and therefore irrelevant to a discussion on hi fi amps! Obviously if an amp is so awful that it's faults are easily audible then it very much will have a particular sound. This is why certain guitar amps are sought after, their very high distortion and other ills give them a distinctive sound that, along with the very coloured guitar speaker, give a sound that can be said to be "the original live sound of that guitar and amp", part of the creative process if you like. The last thing we want is such "editorial decisions" on the sound being applied to everything coming from a hi fi system.
 
tuga said:
Why would anyone voice a SS to sound like Valve? Schiit, people are voicing amplifiers... :rolleyes:
Click to expand...

It's been done loads in guitar amps but not usually in hi fi amps. I certainly never do it and in fact I regard the concept of "valve sound" as somewhat exaggerated... mostly it's the sound of output transformers and low or no NFB
 
Arkless Electronics said:
Such amplifiers are not hi fi and therefore irrelevant to a discussion on hi fi amps! Obviously if an amp is so awful that it's faults are easily audible then it very much will have a particular sound. This is why certain guitar amps are sought after, their very high distortion and other ills give them a distinctive sound that, along with the very coloured guitar speaker, give a sound that can be said to be "the original live sound of that guitar and amp", part of the creative process if you like. The last thing we want is such "editorial decisions" on the sound being applied to everything coming from a hi fi system.
Click to expand...

The OP asked:

PBB said:
How can a designer/manufacturer "voice" an amp without knowing what the speaker chosen by the end user is? Is that based on some crazy assumption that the one component that is the hardest to design is somehow "neutral"?
Click to expand...

I agree that such amplifiers are lower-fi, but they do exist.

And the example I gave actually measures well with the exception of the top-end roll-off and the high low-order HD and a bit too much IM.
 
tuga said:
The OP asked:



I agree that such amplifiers are lower-fi, but they do exist.

And the example I gave actually measures well with the exception of the top-end roll-off and the high low-order HD and a bit too much IM.
Click to expand...

The vast majority of hi fi amps are SS high feedback designs and so pretty universally applicable.

The issues you mention re the Ayre are typical of low feedback designs but can often be rather ameliorated.

For best results in a zero or very low feedback amp it really needs to be class A as most of the output stage distortion mechanisms which the NFB corrects are either not present or hugely reduced in a class A amp.
 
Re. valve and transistor I’ve only ever heard one valve amp, the Radford, and I can’t hear a distinctive valve sound. But my main reason for posting here is to see what you all think of this claim about the limitations of “most transistor electronics” which comes from the marketing literature for the Audio Innovations Alto - an amp I’m very fond of. I don’t understand the idea of tonal ans and dynamic coherence.

It has always been the ambition of Audio Innovations to manufacture products with the best possible performance at any given price. To date, this has precluded the use of transistor circuitry as it was not felt to offer equivalent performance to similarly priced valve designs. . . Audio Innovations places great emphasis on reproducing music with a high level of tonal and dynamic coherence. This consistency, regardless of level or pitch, is fundamental to the accurate reproduction of instrument timbre and is absent in almost all transistor electronics. The Alto circuit configuration addresses the key areas where problems occur while its inherent simplicity allows a more faithful representation of the music to be presented to the loudspeakers.
Click to expand...

https://stereonomono.blogspot.com/2018/11/audio-innovations-alto-amplifier.html

(The idea that some amps can do timbre and some amps are just grey seems really true to me. The Rotels I’ve heard, for all their virtues, don’t do timbre well. AI’s idea seems to be that doing timbre is easier with valves than with transistors.)
 
mandryka said:
Re. valve and transistor I’ve only ever heard one valve amp, the Radford, and I can’t hear a distinctive valve sound. But my main reason for posting here is to see what you all think of this claim about the limitations of “most transistor electronics” which comes from the marketing literature for the Audio Innovations Alto - an amp I’m very fond of. I don’t understand the idea of tonal ans and dynamic coherence.



https://stereonomono.blogspot.com/2018/11/audio-innovations-alto-amplifier.html

(The idea that some amps can do timbre and some amps are just grey seems really true to me. The Rotels I’ve heard, for all their virtues, don’t do timbre well. AI’s idea seems to be that doing timbre is easier with valves than with transistors.)
Click to expand...

It's pure arse gravy.
 
PBB said:
How can a designer/manufacturer "voice" an amp without knowing what the speaker chosen by the end user is? Is that based on some crazy assumption that the one component that is the hardest to design is somehow "neutral"?

Thanks.
Click to expand...

Good questions!
I don't know how/why, other than to say that the human ear/brain has some astonishing capabilities (and some significant shortcomings) and it seems to be quite easy to hear the characteristis of different amplifiers with different speakers, in different rooms and with different music.
 
I couldn't hear any difference between a Supernait 2 (£3200) and a 1999 Audio Analogue Puccini SE (£242 on eBay) used with my sources and speakers ...except that (unlike the Supernait) the Puccini SE is completely silent when not playing.

The Puccini has a standby mode, whereas the Supernait only has an on/off switch awkwardly positioned (seemingly deliberately) at the back. Bye-bye Supernait, with much regret for the £3200 (but not for the amp).

It's speakers that sound different...
 
Arkless Electronics said:
It's pure arse gravy.
Click to expand...

You will enjoy this one:

Why is Timbre Lock important? This is where things get a bit complicated—and controversial. De Lima suggests that an amplifier of relatively high distortion, when combined with a given speaker, can actually produce less total system distortion than the same speaker driven by an amp of lower distortion. According to this view, a higher-distortion amp may sound superior to a lower-distortion one not just because low distortion in an amplifier is usually achieved through the use of greater negative feedback, tilting the distortion spectrum toward the more objectionable higher-order harmonics (the standard argument against designing for ultra-low measured distortion), but because if the amplifier's distortion is opposite in polarity to that of the speaker, the resulting cancellation of harmonics will result in less system distortion.

In general, amplifier distortion and speaker distortion will add or subtract in complex ways that are functions of the phase differences between the amplifier and the speaker, speaker phase being variable with frequency. You might say that when it comes to combining amplifier and speaker distortion, more can be less and less can be more. The Timbre Lock bias settings provide a way of fine-tuning the Eighty Eight's distortion spectrum to produce more optimal cancellation of the speaker's distortion.

https://www.stereophile.com/content/audiopax-model-eighty-eight-monoblock-power-amplifier-page-2
 
I really don't know how amplifiers are built or designed, but different brands of amplifiers do sound different. Professional reviewers seem to talk all the time how a new amplifier has been deliberately 'voiced' in order to capture such and such aspects of sound while sacrificing such and such of sound; as if the designer had a box of cut out slips with written aspects of sound eg one slip to read 'Good Decay' another to read 'Strong Bass' a bit how Bowie used to write song lyrics by dipping his hand into a collection of slips and choosing one which has one line of lyrics. One thing for sure Naim Audio like to add a bit of pep (Red Bull?) into their sound, so that the converted can tap their feet and the other half will block their ears not to hear the artificially induced Rhythms.... Maybe at the end of the day all the brands are not here for some musical artistic merits, but to sell their gear and try to make their product stand out from its competitors, sometimes at competitive prices....
 
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