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From: dh@vax135.UUCP (David N. Horn)
Newsgroups: net.audio,net.analog
Subject: Re: Amp designs (Re: current-dumping amplifiers)
Message-ID: <1569@vax135.UUCP>
Date: Thu, 28-Aug-86 23:53:26 EDT
Article-I.D.: vax135.1569
Posted: Thu Aug 28 23:53:26 1986
Date-Received: Fri, 29-Aug-86 05:48:52 EDT
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Organization: AT&T Bell Labs, Holmdel, NJ
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Xref: mnetor net.audio:2425 net.analog:845

As far as I recall, the "Current Dumping Amplifier" was a name given to an
interesting design of amplifier introduced by Quad (name of a Hi Fi manufacturer
in England headed by Peter Walker) about ten years ago.
It had two amplifiers for each channel, one high power but slow amplifier to
do most of the work, and one low power but fast. A comparator sensed the 
difference between the input signal and the output divided by the gain (i.e.
the distortion), and the fast amplifier made up the difference.
The technique was also known as "feed-forward".
A number of articles on current dumping were published in "Wireless World".
By the way, Peter Walker has a very good reputation for producing top quality
products way ahead of their time.

	Dave Horn, AT&T Bell Labs, Holmdel, vax135!dh