From david–(at)–ahul.net Sun Sep 8 11:29:44 CDT 1996
Article: 14305 of rec.audio.tubes
From: David Josephson
Subject: Re: Memory distortion: why tubes sound better
Date: 8 Sep 1996 08:32:51 GMT
Organization: Josephson Engineering
References: <322E8BDB.70E--(at)--renoble.rxrc.xerox.com> <3231A0A0.3F7--(at)--iverstyx.com>
>>Mike Glantz wrote:
>>> A couple of months ago, someone posted a short article saying
>>> that someone had done some research which demonstrated a new
>>> way of measuring distortion which would explain why tubes sound
>A paper entitled “Measurement of a Neglected Circuit Characteristic”
>was read at the 100th Convention of the Audio Engineering Society,
>May 11- 14 1996 in Copenhagen. The author of this paper is Gerard
>Perrot and it is available as Preprint # 4282 (T6) from the AES.
>This paper presents a measurement method for circuit memory.
>The author proposes and I agree that the signal “memory” of
>cicuits and cicuit components is a form of distortion that correlates
>well with listening test.
In brief: current through components heats them up, causing shifts in
operating parameters so that the circuit in the moments after a loud
sound is different from the same circuit after not so loud sounds.
Perrot has a patent on a solid state circuit topology that eliminates
this. The AES paper is well written, as is the patent. He’s also
written a broader paper on the problem, including some earlier
discussions published in the French magazine l’Audiophile under the
pseudonym “Hephaistos” that explains these theories, and measurements
to reveal them.
David Josephson / Josephson Engineering / San Jose CA / davi–(at)–osephson.com