He did it by duplicating an amplifiers transfer function. There is an article in an older Stereophile where this is discussed. I think it was referring to Carvers Silver 7 amplifiers.

Start at a place like MIT. You begin by getting a very good degree in electrical engineering, enough to know how to design a pretty good amp in the first place, and then you buy two amplifiers. One very good amp to copy and one not too bad an amplifier to modify. And a bunch of parts.

Oh, yeah, being a bit of a genius and a bit of a smart ass help too. I don't know where you get a degree in either of those areas.

Unfortunately there are a lot of the latter to few of the former and very few of both in one. I wonder when DUP will see this thread.

Be a better ad maker than others is what makes it happen. How come all his "genius" "break throughs" never held the test of time. Dave Hafler's Stereo 70 tube amp is STILL being used decades after being introduced, and not mfg'd ..let's look at using MOSFETS..in amps...that is a common thing now...first to do it Dave Hafler...seems his "GENIUS" lives on. Dave Hafler's "DynaQuad" ambient recovery system, an early passive 4 channel system, way ahead of others, we now have surround sound, which "DynaQuad" mimiced. Magnetic cube amps...SoundCraftsmen had small high powered amps without the BS attached (using MOSFETS). Market it with great full page ads, genius is formed. How many of the brands survived, none...no Carver, no Phase Linear, Sunfire has been bought out. I love the ads from the mind and soul...and there really is a Bob behind every product...oh really comparing all them nameless corps making other brands...who is the nameless corp behind the latest company?..., what does that have to do with quality electrical engineering? Harman Intl' actually has Harman people running it, one of the originals, and a daughter, Harman being a massive "faceless" corp, with numerous top end brands, for pros and consumers. He also trys to move lotsa air with undersized woofers, another breakthrough!!! Physics doesn't allow it to happen without issues. How many original Phase Liner are coveted as being so great, all I ever hear is harsh, non musical etc etc...genius at work. and of course let's see AVA been in business almost 40 years, under one name, STILL making the best stuff priced for mortals...now that's enduring GENIUS.

DUP - You seem to ascribe your own narrowly defined personal tests for "genius" to my comments. Not to mention shifting the argument away from the real topic. Is this not an attempt at creating a straw man who is then easily toppled? Bravo for your lessons learned in debate class but shame on you for not sticking to the topic at hand.

The question was not whether Hafler, Harman or VanAlstine should be considered in the genius category, in most civilized discussions they should, and it certainly was not whether more components should contain MOSFETs. But rather the original poster asks what made Carver's feat possible and how would someone go about duplicating the accomplishment. Whether company names survive, which Dynaco did not under any management at any time, the genius of Bob Carver is that he is one of the most recognized names in audio and marketing. Along with Amar Bose, his name and products invite comment from virtually anyone involved in audio. Carver's companies are not nameless products manufactured by committees nor family members. In fact, they are often signed by the man behind, and more likely in front of, the product. Like him (and his products) or not, Carver will live as a legend in audio for more than one product and more than one accomplishment. Whether that accomplishment is taking on the subjective press and whether you agree with the process or the results is not the question at hand. Walk into an audio shop of any calibre and mention both Frank VanAlstine and Bob Carver and notice who garners the most comments. DUP, if only you could broaden your scope a bit more (while confining your comments to the discussion topic), you might easily see where Mr. Carver's true genius exists. Ask anyone next time you're in a Best Buy or Circuit City. They'll tell you.

If we are getting off topic, might I ask a question. Firstly, do not mistake my opinion of the ST70 amplifier, I consider it the best place for anyone interested in tubes to begin listening. However, can an amplifier truly be considered great when virtually everyone using the amplifier alters the original circuitry? Isn't "great" a title that should be reserved for amplifiers such as a McIntosh MC275 or a Marantz 8B which live on in daily use just as they were manufactured forty years ago? The ST70 is almost an amplifier that is so modified from its origins it can be difficult to recoginze as the original product. Often all that is left of a ST70 after the modifiers have their go at the amplifier is the chassis. If that even! How exactly does that qualify as a "genius" product?

And, just as a note, do not the current surround formats mimic DynaQuad and not the other way around? Would we have ever had ProLogic if there hadn't been a DynaQuad circuit?

That's right the Best Buy and Ckt City mass fi know Carver well. Same with BLOSE. they won't know VanAlstine, Legacy (they think it's a car stereo!!) They will know Sound and Vision magazine, not StereoPhile or Absolute sound. Or Pro sound News or Pro Audio review. They won't know EAW, SLS,Harman Pro,Furman, QSC,Benchmark,HHB, Tascam, Magnum DynaLab, Hafler,Rane, They won't know Sweetwater or Musican's Friend, but they know all the best audio comes out of Ckt City and Best Buy. In a box for $299. amp and speakers!!!! How could anybody spend more, it's a sony the best!!! ...numerous other top quality brands. As I said, Carver is a marketing guy, just like BLOSE.

DynaQuad is the "genius" of Dave Hafler. James Bongiorno worked with Hafler on the first high powered Hafler item the Dynaco ST400, non Mosfet. Later Hafler left Dynaco..(sold it) and started Hafler. Hafler began his audio road in the 50's as a transformer company. Long before Bob Carver, long before any of em actually. Fisher, Kloss,Vilchur..some of the REAL audio genius. Not marketing only genius. The early guys started it all. AND their ideas and CONCEPTS keep on giving, not so with a carver idea. Fads fade, genius endures. Leo Fender and Les Paul....musical GENIUS...that keep on giving

So we aren't going to talk about how Carver managed his tricks with amplifiers any longer, eh? And you make no mention of the ST70 modifications. I guess you don't consider it Hafler's greatest achievement.

Unfortunately, if you consider DynaQuad to be the "genius" of David Hafler, you don't leave him much of a legacy there either. Three channel phantom circuits were first demonstrated in 1934 by the Bell Telephone Labs engineers. From the notes I have J. C. Steinberg and W. B. Snow were the engineers in charge of the demonstration. Paul Klipsch, a name now familiar to the Best Buy crowds, demonstrated further developments in three channel operation with a derived phantom center channel using two channel source material in October, 1957. His papers can be found in the April, 1958 Journal of the Audio Engineering Society. These circuits involved a "summed" center channel that was used with flanking corner speakers. However, in 1959 Klipsch again presented to the Society a demonstration of a passive mixing circuit designed to utilize "difference" information and deriving three channels from two channel source material. Once again the intent at the time was to use a center front speaker with the derived difference signal offering a better depth presentation to the new stereo format.

It is, however, a very short walk from these derived sum and difference circuits to the DynaQuad circuit Hafler introduced. I can't pin down exactly when Hafler first "introduced" the DynaQuad circuit, but apparently the QD-1 adapter wasn't placed on the market until 1971, some 34 years after the first derived passive matrix circuits were demonstrated by Bell Labs and a dozen years after Klipsch's demonstration. While Hafler and his cohorts can be credited with many achievements in consumer audio, I would think there are better examples of Hafler's "genius" than the "derived" DynaQuad circuit.

Dave Hafler took the Wiliamson ckt (UltraLinear?) and made his original tube amp kits that changed the world of consumer high fidelity. PAM 1 some Mk1 amps etc. Dave Hafler brought top quality sound high reliabilty products to the people in the 50's all the way through the 70's. First to use MOSFETS in audio amps. Saul Marantz did more than any Carver idea ever did, Marantz brand, is STILL being sold, under new ownership. Marantz was another early creator of the hi fi business. Carver wasn't, isn't, can't be.

Quote:
Dave Hafler took the Wiliamson ckt (UltraLinear?) and made his original tube amp kits that changed the world of consumer high fidelity. PAM 1 some Mk1 amps etc. Dave Hafler brought top quality sound high reliabilty products to the people in the 50's all the way through the 70's. First to use MOSFETS in audio amps. Saul Marantz did more than any Carver idea ever did, Marantz brand, is STILL being sold, under new ownership. Marantz was another early creator of the hi fi business. Carver wasn't, isn't, can't be.

Be still my heart! A DUP post without one mention of Legacy Whispers, et al. that was pretty readable!!! Sorry for this off-topic interjection, but, this is a moment to behold. You should see the smile on my face. Perhaps, there is hope.

Yes, Hafler and Keroes took the Williamson amplifier and tapped the transformer at a different point. So had Peter Walker for his Quad tube amplifier and Gordon Gow and Frank McIntosh for the Unity Coupled design. And all of these designs owe a debt of gratitude to Blumlien's work a decade earlier.

(http://home.indy.net/~gregdunn/dynaco/history.html)

Imitation is the sincerest form of flattery.

And your point is?

That seems to be a good question; what is your point, DUP? That you hate Bob Carver and can't see how he fits into the audio world without being a "Carver Hater". Seems as short sighted as declaring the DynaQuad circuit Hafler's "genius". In his own way Hafler successfully marketed his twist on other people's work. He is, in effect, a marketing genius. I believe you were closest to the truth when you inferred that the pioneers of audio existed long before Bob Carver. That, however, doesn't lessen what Carver has done. And, make no mistake, I have no desire to own nor affection for any of Carver's products. My point is it doesn't make sense to bash someone mercilessly just because you don't like their designs. Who died and left you editor of "Recommended Products"?