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From: john@newave.UUCP (John A. Weeks III)
Newsgroups: sci.electronics
Subject: Re: Power supplies for audio amps
Message-ID: <822@newave.UUCP>
Date: 10 May 91 02:20:14 GMT
References: <1991May9.120758.20464@umbc3.umbc.edu>
Reply-To: john@newave.mn.org (John A. Weeks III)
Organization: NeWave Communications Ltd, Eden Prairie, MN
Lines: 39

In article <1991May9.120758.20464@umbc3.umbc.edu> hack@math13.math.umbc.edu writes:
> I have a question about the power supplies used in high
> power hi-fi audio amplifiers.  I would assume that the power
> supplies are voltage regulated.  The question is can switching
> power supplies be used or are linears required, assuming the
> power supply will fit into the same box.

For the most part, the power supplies are voltage regulated linear
power supplies.  The key factor is the peak current available.  Musical
peaks may come along that surpass the current capacity of the power
supply itself, so most high end amps have huge capacitors for current
reserve.

For the most part, switching power supplies are too noisy to be used for
audio amps, and switching supplies like well behaved steady loads, not
something like music.

There are amps available with wierd power supplies, but they tend to
be for specialized purposes.  Class C amps work good for voice, but
not for music.  They are used because they are very efficient.

Soundcraftsman used to advertise something called class 'H' amps.
These were basically two stage amps that had a quality low power amp
plus an extra high power stage.  The high power stage could not run
continious duty, so it was used only for peaks.  The end result was
a quality low power amp the acted and sounded like a much more powerful
amp.

Carver designed the most unique audio amp that I ever encountered.  It
is advertised as a magnetic field amp.  It had a high power rating but
was far lighter and smaller than conventional amps.  What I suspect is
that Carver used the input signal to somehow modulate the power supply.

-john-

-- 
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John A. Weeks III               (612) 942-6969             john@newave.mn.org
NeWave Communications, Ltd.                        ...uunet!tcnet!newave!john