itsgriffo

Who's been a good amp designer then?

26 posts in this topic

I noticed a comment by Zaphod in another thread praising Nelson Pass as a good designer of amplifiers. Some others names appear pretty regularly in the mainstream press, Like Bob Carver, John Curl (Parasound), BEE (NAD), Bruce Candy (Halcro) etc etc.

I was wondering who else was rated highly by the more electronically-literate out there and why?

Best,

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I noticed a comment by Zaphod in another thread praising Nelson Pass as a good designer of amplifiers. Some others names appear pretty regularly in the mainstream press, Like Bob Carver, John Curl (Parasound), BEE (NAD), Bruce Candy (Halcro) etc etc.

I was wondering who else was rated highly by the more electronically-literate out there and why?

Best,

Peter Stein (of course). Here's why:

Peter started his business back in 1976. Most of his ideas were crystallised and in production by 1977. They were revolutionary back in 1977 and still rare in 2009. They included:

* Massive current capability (his first amp was capable of delivering 40 Amps - It was a 50 Watt/ch amp).

* Over-sized power transformers.

* The use of high speed, very low distortion output devices.

* Zero Global Negative Feedback for power amps AND preamps, without sacrificing objective performance.

* The use of carefully and critically matched components where required (transistors are/were matched to within 1% and certain resistors and caps to within 0.05%).

* Minimal distance between filter caps and output stages.

* The selection and use of low inductance capacitors (later, to be custom manufactured for him).

* True dual mono operation. (Not stereo)

* Soft Voltage limiting (clipping).

* Soft current limiting.

* High bias/high temperature operation.

* Multiple capacitor, very low inductance capacitor banks.

* Frequency/phase response matching for individual phono cartidges.

* The facility to upgrade all products at a later date.

* No fuses in the signal path. In fact, no fuses, save the mains and transformer thermal fuses.

* No relay contacts, nor switch contacts in the signal path.

* No inductors in the signal path - Output impedance is almost purely resistive from DC to 50kHz.

Very few of the above features existed in transistor amplifiers back in 1977. Some did exist in valve amps, however. Peter merely duplicated some of the best features found in good quality valve amps and applied those features to transistor amps.

Peter counts amongst his influences these people:

* John Curl.

* Ken Ishiwata.

* Jim Bongiorno.

* Matti Otala.

* Saul Marantz.

* Many other valve amplifier manufacturers from the 1960s and 1970s.

Apologies if this sounds like an an advert. It is not meant as such. Peter Stein is a much under-rated designer of prodigious talent.

Edited by Zaphod Beeblebrox
Brain fart

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Have Peter's designs been mimic-ed or copied? If so, which manufacturers?

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Have Peter's designs been mimic-ed or copied? If so, which manufacturers?

I am unaware of any manufacturers who have directly copied Peter's designs, though that is certainly possible. I am aware of a few manufacturers who have employed some of Peter's innovations well after he released them. I am unaware of any manufacturer that employs ALL of Peter's innovative ideas in a single package (even today). Here's a couple of manufacturers who released ideas of Peter's long after 1977 (I am NOT suggesting that these manufacturers copied Peter's designs - just that they released their products long after Peter released his):

* NAD - Soft Voltage limiting.

* NAD - High current capacity.

* Harman Kardon - High current capacity.

* Classe' - Multiple capacitor banks for low inductance.

* Krell - High current capacity.

* Krell - Very large power supplies.

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My number one choice would be Tim de Paravicini currently of EAR (Esoteric Audio Research) / EAR Yoshino. Fantastic innovative Valve and Solid State Amps. He was also previously chief designer at Lux Corporation, Michealson and Austin, and design advisor to many current companies. In 1976 he released amps with valve power of 100 W/PC with bandwidth of 9Hz to 85KHz (-3db). He even designed his own valves for some of his designs.

Second for me would be Nelson Pass.

Also worthy of high praise would be;

Arthur Radford - early valve designs;

Peter Walker of QUAD;

Julian Vereker of Naim Audio;

William Z Johnson of Audio Research;

Hiroyasu Kondo;

Ralph Karsten Atma-sphere;

David Hafler.

Also the previously mentioned;

John Curl;

Matti Otala;

Ken Ishiwata;

It would be interesting to know how many of the "great designers" were team leaders, and, the actual designers were never heard of.

Ken

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What about Trevor Lees?

He was the first Australian designer to have any overseas sucess with his pre amps and moving coil pre pres back in the late 70s.

Herby

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what about peter qvortrup and andy grove,a new power amp [P 4 Balanced] with these in the signal path,3 transformers,2 superlinear direct-heated triode gain stages,2 tantalum resistors and no capacitors.minimalism at its best.i'll let you know how they sound in about 4 months time.

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Didn't sound like an ad at all Zaphod and I appreciate your and others interesting insights.

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i personally love the look of the NAD stuff

but what about the Moon products, sorry if the designer has already been mentioned

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Nelson Pass is the best for several reasons. Creative, imaginative designer who shares almost all of his IP and knowledge with the DIY community and doesn't go in for a lot of BS.

Tom Danley would be his equivalent in the speaker field.

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New hear. Always been a fan of John Iverson of electro reasearch and electron kinetics amps. Used large power supplys with massive currant capabilitys, bass power and control unmatched in there day

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nice write-up ZB - the things you listed are things that I have come to benefit from in my current setup, be-it a valve one.

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If we are including tube gear, I would suggest the Vacuum State guys. Allen Wright and Joe Rasmussen have done good things with phono, pre and SE power amps. Also some early work on the gainclones.

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What about Patrick Turner? Another Aussie that should get a 'PLUG' on SNA surely.:)

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+1 National Semiconductor. Who else can deliver the goods at $15?

Hugh Dean

And that Brazilian guy at diyaudio.

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Elson Silva from Cymer Audio here in Sydney makes superb valve amplifiers.

They're dead quiet, ultra reliable, well-engineered, look the part and sound very, very good.

Cheers,

EK

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Bill Conrad & Lew Johnson - of conrad johnson

Sidney Corderman of McIntosh

David Manley of VTL and Manley

Vladimir Lamm of Lamm amps

Flemming E. Rasmussen of Gryphon amps

The guys at B & O behind ICE amplification

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What about Bill Crampton at Merlin Audio Design? Listened to his amps before and was very impressed, albeit they are a bit ugly looking and not cheap.

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What about Patrick Turner? Another Aussie that should get a 'PLUG' on SNA surely.:P

Yes certainly considering his self taught history in electronics he makes some serious valve amps apparently.

He freely shares his designs which you can see on his website.

Cheers,

Alan R.

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+1 Patrick Turner

Have John McCormack, John Curl and Dan D'Agostino been mentioned?

EK

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