From david–(at)– Sun Sep 8 11:29:44 CDT 1996
Article: 14305 of
From: David Josephson
Subject: Re: Memory distortion: why tubes sound better
Date: 8 Sep 1996 08:32:51 GMT
Organization: Josephson Engineering
Lines: 32
Message-ID: <50u0bk$kc--(at)>
References: <322E8BDB.70E--(at)> <3231A0A0.3F7--(at)>
NNTP-Posting-User: davidj

In harr–(at)– (harry kolbe soundsmith inc.) writes:

>>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)–


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