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From: ed@maxed.amg.com (Ed Whittemore)
Newsgroups: rec.audio.high-end
Subject: Re: Power Hog Class A Amps
Message-ID: <6556@uwm.edu>
Date: 24 Sep 90 12:52:33 GMT
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Approved: tjk@csd4.csd.uwm.edu

In article <6535@uwm.edu> tomp@vicom.com (Tom Pohorsky) writes:
>>Audio Research Classic 60 power amplifier draws 370W at idle.
>>That's far more than your refrigerator draws when its running.
>>is it really necessary for a class A amp to draw this much power at idle?
>
>If a Class A amp in "on" and ready to operate, it will be drawing
>bigtime power, by the very nature of class A. There are a few
>companies that recognize the waste in this, and have an "idle"
>mode that keeps the machine warmed up without drawing the big
>power that class A bias warrants. Counterpoint maybe ?? Anyone
>know specific brands/models that do this ??
>
The solution here is to get a variac, and step down the voltage to
the amps about 75%, or say 30 volts. You also protect the tubes from
the on/off transients. For solid state equipment I don't know what
you would do.

Anyway, after listening to some high powered Class A amps such as
a Krell KSA-250 and VTL Ichibans with only 1/2 hour of warm-up vs.
a full day I can't say that there is too much, or any, difference
in sound. Your mileage may vary.

So I don't think the clear inefficency of Class A amplification
poses either a practical or ethical problem--it is OK to turn the 
equipment off/bring down the voltage, and the extra pennies burned
while playing music (it is only pennies), are more than compensated for
by Class A sound.
-- 
Ed Whittemore   uunet!maxed!ed   ed@maxed.amg.com
American Micro Group, Inc.   201-944-3293