Author Topic: The carver challenge ...  (Read 662 times)

Offline muddda

The carver challenge ...
« on: November 23, 2021, 06:08:44 PM »
"In 1985 Stereophile magazine was edited by J. Gordon Holt and published by Larry Archibald. (John Atkinson was still editing HiFi News in the UK and wouldn’t take the reins until one year later.) As the story goes, Carver, sometimes known as Captain Bob for his signature blue cap with a gold anchor emblazoned on the front, bragged to Larry Archibald “that he could make his $700 Model 1.0 amplifier sound “indistinguishable from” any amplifier of Stereophile’s choice”, Larry took him up on the challenge. This became famously known as The Carver Challenge."

https://www.stereophile.com/content/carver-challenge

Fascinating ....

your guys thoughts ?

Offline Baseline

Re: The carver challenge ...
« Reply #1 on: November 23, 2021, 07:21:59 PM »
Very interesting article indeed and proves to me at least, that my ears have been correct all along in noting that certain "mid-level" brands can sound very close to and on occasion identical to, certain "high-end" brands. There is at times no true justification for the exorbitant price attached to an item other than the status attached to the brand.
.It's all about the Music.

Offline simpletonion

Re: The carver challenge ...
« Reply #2 on: November 23, 2021, 10:16:44 PM »
So, the mythical giant killer (matcher?) exists.

The outcome jibes with @Ampdog's claim made in an earlier thread - a claim that, as was the case for the writer of the linked article, initially rendered me incredulous.

Now, someone do this with loudspeakers please.

Offline Shonver

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Re: The carver challenge ...
« Reply #3 on: November 23, 2021, 10:25:43 PM »
The outcome jibes with @Ampdog's claim made in an earlier thread - a claim that, as was the case for the writer of the linked article, initially rendered me incredulous.

What exactly do you understand @Ampdog to have said?
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Offline simpletonion

Re: The carver challenge ...
« Reply #4 on: November 24, 2021, 07:42:59 AM »
Best to read the man's words here.

https://www.avforums.co.za/index.php/topic,93877.60.html

---------------------------

Another interesting aspect of the article in the OP is that achieving the 'deep null', while necessary, does not seem to have been a sufficient condition for "success" (even if those are/were "some of the most highly trained ears in the world" doing the evaluation, it remains a subjective assessment) in this case.


Offline fdlsys

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Re: The carver challenge ...
« Reply #5 on: November 24, 2021, 11:13:10 AM »
Before the half-baked invalid conclusions and swords are drawn, understand this:

(1)
Bob Carver is a bona fide genius who was on top of his game at that time and had a strong commercial motivation to prove his point.
The method of duplication he used was hardly rocket science - it was in use at least since the 50s and not his invention.
From the net: "Carver, used null difference testing, (null difference testing consists of driving two different amplifiers with identical signal sources and exact levels, but out of phase by exactly 180 degrees"
Note the underlined text above - same levels.

(2)
The amp he used was uniquely well suited for the purpose. GREAT amp, designed by him, enhanced by him, tweaked by him. No other commercially available amp EVER IN HISTORY had what it takes to allow this kind of tweaking.

So no - no average NAD, Rotel, Marantz, etc. (put literally ANY brand here) will EVER sound anywhere close to Mark Levinson Class-A amp nor Conrad-Johnson valve amp. Dream on; never gonna happen. For ANY amp to sound like any other amp, it has to be designed and tweaked for that specific purpose. And no, you cannot do that with average amp design - they simply don't have the basics required for this.

Even then, it will only sound as the original amp at a single point on the gain curve. The level at which the "sonic transfer" (NULL test) was performed.

The above generalisation SPECIFICALLY excludes everything that is NOT AVERAGE - for example, Hitachi 7500mkII pre/power amplification (someone has them advertised right now so that reminded me) is another league and sounds FAR better than what the brand or price bracket would suggest. But it is an (or one-of) exceptions that validate the rule - it was designed to PROVE THE POINT. Hitachi's point was that they are the manufacturer of best commercially available semiconductors; specifically FETs, and their claim was well proven.

Conclusion:
If you have a chance to buy some of historic Carver amplification that was well regarded and reviewed and proven reliable over decades, by all means do so. Great amps. Great designs. Great talk-point. Great looks. GREAT piece of audio history.

Do not expect that any commercially manufactured mediocre bling is going to sound like big boys. It won't. Never, ever.
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Offline xumbug

Re: The carver challenge ...
« Reply #6 on: November 24, 2021, 10:24:35 PM »
Before the half-baked invalid conclusions and swords are drawn, understand this:

(1)
Bob Carver is a bona fide genius who was on top of his game at that time and had a strong commercial motivation to prove his point.
The method of duplication he used was hardly rocket science - it was in use at least since the 50s and not his invention.
From the net: "Carver, used null difference testing, (null difference testing consists of driving two different amplifiers with identical signal sources and exact levels, but out of phase by exactly 180 degrees"
Note the underlined text above - same levels.

(2)
The amp he used was uniquely well suited for the purpose. GREAT amp, designed by him, enhanced by him, tweaked by him. No other commercially available amp EVER IN HISTORY had what it takes to allow this kind of tweaking.

So no - no average NAD, Rotel, Marantz, etc. (put literally ANY brand here) will EVER sound anywhere close to Mark Levinson Class-A amp nor Conrad-Johnson valve amp. Dream on; never gonna happen. For ANY amp to sound like any other amp, it has to be designed and tweaked for that specific purpose. And no, you cannot do that with average amp design - they simply don't have the basics required for this.

Even then, it will only sound as the original amp at a single point on the gain curve. The level at which the "sonic transfer" (NULL test) was performed.

The above generalisation SPECIFICALLY excludes everything that is NOT AVERAGE - for example, Hitachi 7500mkII pre/power amplification (someone has them advertised right now so that reminded me) is another league and sounds FAR better than what the brand or price bracket would suggest. But it is an (or one-of) exceptions that validate the rule - it was designed to PROVE THE POINT. Hitachi's point was that they are the manufacturer of best commercially available semiconductors; specifically FETs, and their claim was well proven.

Conclusion:
If you have a chance to buy some of historic Carver amplification that was well regarded and reviewed and proven reliable over decades, by all means do so. Great amps. Great designs. Great talk-point. Great looks. GREAT piece of audio history.

Do not expect that any commercially manufactured mediocre bling is going to sound like big boys. It won't. Never, ever.

+1000 :thumbs:
SDA Acoustics loudspeakers, Audio Research Ref 3 Pre amp and Ref 210 power amps, Bel Canto VB3.5 Dac, Pathos Endorphin cd player, squeeze box touch.

Offline Ampdog

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Re: The carver challenge ...
« Reply #7 on: December 02, 2021, 01:06:01 AM »
Your post #5,   Fdlsys:

Brave bold words those Mike - - but they overlook one of the basics of human hearing:  The fact that said hearing has limitations; that distortion (in its broadest sense) can only be detected if AUDIBLE! Thus it is in fact quite easy to design a "blameless amplifier". to use the term 'coined' by Douglas Self decades ago.

The null-method is in fact a powerful means of comparing 'amplifier sound', when whatever is distilled out by this method is audible!! (sorry golden-ears!)  For decades now 'blameless' amplifiers have been designed which did not affect the sound in an audible manner. Not (certainly!) to (re-re-re-)open this thorny subject here, but with knowledge gained from hearing tests and modern sensitive analysing equipment, it can be simply and easily determined whether or not an amplifier will affect a signal in an audible manner, without having to organise blind hearing tests.
Audio must be the only branch of engineering where lack of basics' knowledge is considered a superior form of wisdom. (Anon)