all good amps sound the same ?

[Jeffery]

Bob Carver famously did exactly that, within 48 hours, to win a challenge posed by a magazine. He made solid state "clones" of two very famous tube amps (I think one was a Conrad Johnson), and in blind listening tests, the "experts" cound not tell the difference between the SS and the tube amps.

Why would he need to do that?

If all amps sound the same, the entire premise of tweaking one amp to sound like another just seems pointless. Plug in any two non-defective amps, level match them, and you just won the Carver Challenge.

 

[Pio1980]

Why would he need to do that?

If all amps sound the same, the entire premise of tweaking one amp to sound like another just seems pointless. Plug in any two non-defective amps, level match them, and you just won the Carver Challenge.

Well, because they don't.

 

[bowtie427ss]

Why would he need to do that?

If all amps sound the same, the entire premise of tweaking one amp to sound like another just seems pointless. Plug in any two non-defective amps, level match them, and you just won the Carver Challenge.

In case you've never read it first hand: http://www.stereophile.com/content/carver-challenge

 

[whoaru99]

Why? Are you kidding? There are countless different topologies and collections of active and passive parts along with differing power supply strategies.

While basic measurements are insufficient to fully characterize the audible results, the noise, distortion spectra and dynamic behavior are all over the board!

No, I'm not.

I'd say "prove it", but we both know that's not going to happen.

 

[Pio1980]

There is some consensus that all "good" amps tend to sound similar, which is not to say that they sound exactly the same. The exceptions will relate to power handling and whether internal feedback correction loops are present and how well they are implemented for example as well as the nature of loading.

 

[whoaru99]

"Exactly the same" is a red herring. It's likely no two amps perform exactly the same if for no other reason than production tolerances.

The point is whether or not the differences are reliably and repeatably identifiable.

 

[eljr]

an hour ago , i was reading in another discussion that a well designed ss amp would be hard to differentiate from another one if both are similar quality products.

I dont agree.
Reason : sonic signature ????

.

Isn't "sonic signature" really "distortion added?"

 

[Jeffery]

In case you've never read it first hand: http://www.stereophile.com/content/carver-challenge

I'm familiar with the challenge, what I question is the need to ever have done the challenge.

Many experts, some right here in this thread, claim that ABX blind comparisons between level matched, non-defective amps demonstrate that there is no difference.

If that's true, why would there ever be a need for something like the Carver Challenge? Take any two non-defective amps, level match them, and nobody can hear the difference. You just won the Carver Challenge! Why would you need 48 hours of tweaking?

 

[Dclapp]

Yes

I agree that "sonic signature" is certainly synonymous with "added distortion". If the aim of an amplifier is to accurately reproduce the input, what else could it be?

 

[E-Stat]

I might rather listen to them, too. But, that is not here nor there when talking about whether two different solid state amps sound identical, now is it?

Sure it is. Amps sound different because of the profound differences in engineering approach. I submit that the (audible) distortion spectra of Nelson's SIT-1 using a single stage class A no feedback amp using a single transistor is quite different from that of the bridged class AB (suspect more B than A based upon weight and output) amp found in a Lunchbox.

As to Nelson Pass.... a gifted designer for sure, but not a scientist or theoretician.

I live for the real world. How about you?

By, "high performance" you really mean, "high priced." The performance is what is being debated.

Assumptive straw man arguments don't serve your purpose. I'm only too happy to answer any questions you may have about what I think or what I value.

Thanks! Just last week we sold a bunch to ZZ Top (again), Mick Fleetwood, George Benson, Slash and Streisand's band. And Guitar Center. We broke $1M two years ago, and we are tiny.

That sound great. I don't measure the success of a company driven by passion using the gauge of revenue alone. First Watt is similar in that regard.

(Since, the concept of "many other companies" is important to you... What do you suppose the sum total of non-feedback amps sold last year was?)

Significantly less than that of Bose. What do you think?

I don't judge the enjoyment of a Ruth's Chris steak by how many hamburgers McDonald's sells. Similarly, sales volume is not among the criteria by which I judge the ability of an audio component to reproduce the experience of live, unamplified music. Is that one of yours? As for an audio company, I do value innovation and longevity in the marketplace.

In your Stereophile interview, you indicated that you want to make "value-driven products. I think that approach has suited you quite well over the years with what you've designed and produced. Keep up the good work in that corner of the market!

 

[E-Stat]

No, I'm not.

Sorry to hear that.

 

[Dclapp]

To add just one example, I think that it is been conclusively demonstrated that the "tube sound" is the result of harmonics which are not present in the input – distortion, of course – which are not created in most solid-state amplifiers; some of the designs by Nelson Pass (and others, I'm sure) being with the exception. And I'm fine with that; I also find some of those distortions pleasing to the ear

 

[Pio1980]

"Exactly the same" is a red herring. It's likely no two amps perform exactly the same if for no other reason than production tolerances.

The point is whether or not the differences are reliably and repeatably identifiable.

I think "exactly the same " is the point, this seems to be the pivot for the "yes-it-does/no-it-doesn't" gain-saying.

 

[E-Stat]

~ Douglas Self (a truly great designer)

The "truly great" sells DIY kits, right?

If objective measurements are disregarded, it is inevitable that poor amplifiers will be produced, some so bad that their defects are unquestionably audible.

I'll let a far more innovative and successful designer respond to such a misunderstanding of the topic:

" We use negative feedback in audio amplifiers to stabilize the gain, increase the bandwidth, lower the output impedance and lower the non-linear distortion. It is the aspect of reducing the distortion which tends to generate the most controversy – negative feedback is very successful in lowering distortion to very tiny numbers as measured by distortion analyzers.

As Mr. Spock said, “Instruments only measure what they were designed to measure.” * Given the complaints of audiophiles over the sound of high-feedback type amplifiers, it is reasonable to examine non-linear distortion in greater depth than is possible with a single number. * Star Trek, Episode #7, “The Naked Time”

Negative feedback can reduce the total quantity of distortion, but it adds new components on its own, and tempts the designer to use more cascaded gain stages in search of better numbers, accompanied by greater feedback frequency stability issues...

The resulting complexity creates distortion which is unlike the simple harmonics associated with musical instruments, and we see that these complex waves can gather to create the occasional tsunami of distortion, peaking at values far above those imagined by the distortion specifications."

May you enjoy listening to simplistic metrics. Back in the 70s, I got a THD graph of my AR Amplifier conducted by Dave O'Brien of McIntosh labs. Boy, it really looked cool. On the other hand, I quickly sold that amplifier - despite the pretty graph. Somehow, the picture didn't make up for the poor sound quality.

 

[E-Stat]

I have found many amps that do an effectively perfect job amplifying a signal above their noise floor and below their clipping limit. In my listening rooms I have used a Dynaco 410, a Crown Microtech, an Aragon 4004, a Krell KST-100 and various pro sound amps, essentially interchangeably.

Thank you providing your frame of reference and commentary.

I understand fully now.

 

[SoCal Sam]

The answer to the OP's question is no. "Good" is a subjective term which is open to the infinite interpretation made possible by the infinite variation in hearing ability. Even signal accurate amps can be interpreted as being less than good.

 

[Dclapp]

As always, the pejorative "simplistic metrics" is based on the foundational belief that "some things can't be measured".

Which is of course true! I cannot measure my love for my wife or the pain in my left foot – nor can my mate or my physician.

But the question that the subjectivists must answer, if they are truly to make their case, is exactly what audible component of the varying AC output at the amplifier speaker terminals cannot be measured?

I am sure that educated and passionate audio engineers around the world would love to know the answer to this question, if it is something other than "none".

 

[E-Stat]

At that point, you'll have two amps that --no matter what their type or design-- will sound exactly the same.

Using sinusoidal test tones as your reference, yes.

Bob Carver famously did exactly that, within 48 hours, to win a challenge posed by a magazine. He made solid state "clones" of two very famous tube amps (I think one was a Conrad Johnson), and in blind listening tests, the "experts" cound not tell the difference between the SS and the tube amps.

I enjoyed reading an interview with Carver in the August 2008 issue of TAS. When asked about that *challenge*, here is his response:

"I should have said, I can make my amplifier sound close...

Well, I have a secret. I cheated. I practiced a lot before I started! There's a lot going on behind the curtain."

He produces tube amplifiers now, doesn't he?

 

[Brindabella]

There are many very skilled and knowledgeable audio people here at AK. I know nothing about the science, math or design principles of constructing an amp so maybe I should not comment. However, I love reading posts that contradict my personal experience and I try to keep an open mind. But as the owner of at least 10 amps the only contribution I can make is to confirm that each of my amps has its own sonic characteristics.

To the believers that all amps of similar quality sound same, I just can't wrap my head around two issues:

1. Buying vintage, why do some have amps have such pedigree from decades of listening experience.
   
2. Buy new, how do you shop for an amp? I have this picture of you walking with into an audio store with X dollars and saying "I'll have that one cos they all sound same". Surely not??

Enjoy the music

Rob

 

[SoCal Sam]

"Exactly the same" is a red herring. It's likely no two amps perform exactly the same if for no other reason than production tolerances.

The point is whether or not the differences are reliably and repeatably identifiable.

I believe that differences in objective performance can be heard. An amp with perfect square wave reproduction will sound sharper and clearer than an amp with sloped rise and rounding which will sound smoother and less forward in comparison.