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From: ark@alice.UucP (Andrew Koenig)
Newsgroups: net.audio,net.analog
Subject: Re: Amp designs (Re: current-dumping amplifiers)
Message-ID: <5975@alice.uUCp>
Date: Sat, 23-Aug-86 12:04:14 EDT
Article-I.D.: alice.5975
Posted: Sat Aug 23 12:04:14 1986
Date-Received: Sun, 24-Aug-86 03:08:30 EDT
References: <1263@uwmcsd1.UUCP>
Organization: Bell Labs, Murray Hill
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Xref: mnetor net.audio:2413 net.analog:836

> Therefore, current dumping is not only a function of the
> output impedance but also of the power supply current capacity.

My understanding is that "current dumping" is a trademark of the
Acoustical Manufacturing Company in Huntington, England, and refers
to a particular circuit configuration they use in their power
amplifiers (QUAD 403).

The idea is that the output of the amplifier is the difference of the outputs
of two separate parts.  One, called the current dumper, has a lot of
power capacity but only mediocre linearity.  The difference between the
output of the current dumper (divided by a constant) and the input is
then amplified by a smaller amplifier on which considerable care is taken
to minimize distortion.  This is easier to do here because this
amplifier is smaller.

Its proponents claim that this is a way to get a lot of power with
very low distortion and only a little more design effort than would
be necessary for a much smaller amplifier.

I am not qualified to evaluate this claim.

> As an aside, anyone ever think of desgning large complimentary solid state
> amplifiers with no power transformer for 120VAC?

I think it would be an incredible safety hazard.