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From: sbhattac@sales.gba.nyu.edu
Newsgroups: rec.audio.high-end
Subject: Re: Leaving components turned on.
Message-ID: <8613@uwm.edu>
Date: 31 Dec 90 15:08:31 GMT
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Approved: tjk@csd4.csd.uwm.edu
Originator: tjk@csd4.csd.uwm.edu

In article <8587@uwm.edu> hqyy@vax5.cit.cornell.edu writes:

>        On the subject of leaving components turned on as warm improves
>sound quality: inthe case of transistor (or MOSFET) amps or pre-amps
>(such as the mentioned Threshold), this is recommended as the surges from
>turning on and off will tend to damage components and also since the
>parts inside the component will reach and stay at a thermally stable
>environment.

Some designs take account of this. Borbely's amp designs in Audio Amateur
did just that. He chose bias for the Hitachi MOSFETS so as to minimize
temperature effects. Given the device characteristics that I have seen,
that design choice should be highly successful. Each MOSFET conducts about
100 ma quiescent current.

Of course, this has limited applicability to amps where the designer
chooses much higher quiescent current, as in class A amps.

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Shankar Bhattacharyya, Information Systems, New York University
sbhattac@sales.gba.nyu.edu
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