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Path: utzoo!dciem!nrcaero!pesnta!amdcad!fortune!dsd!riner
From: riner@dsd.UUCP (john riner)
Newsgroups: net.audio
Subject: Re: toroidal transformers
Message-ID: <387@dsd.UUCP>
Date: Wed, 30-Jan-85 16:41:43 EST
Article-I.D.: dsd.387
Posted: Wed Jan 30 16:41:43 1985
Date-Received: Fri, 1-Feb-85 21:03:21 EST
References: <202@cmu-cs-h.ARPA>
Organization: AMPEX DSD, Redwood City, CA.
Lines: 23

> I noticed that some high-end amplifiers use toroidal transformers in their
> power supplies, instead of the usual rectangular kind.  Anybody out there
> know why?
> 				    -Olin

Toroidal transformers for Olin' benefit and ant others interested are used
for two primary reasons:
	1. They are more efficient since the field in the core doesn't
		go around corners.
	2. They emit less stray field for somewhat the same reason.
Why havent they been used for ages you ask. Because they are more expensive
to make. The windings must be wound on the core directly (ie. the spool of
wire has to go through the middle of the core) which limits the size to
fairly large cores and it takes special winding equipment, wheras for the
rectangular type, the coils are wound on Bobbins en masse and the core is
assembled into the bobbins. Also the availability of certain core materials
and processes has only recently (last 5-10 years) become reasonable from a
cost standpoint.

-- 
	John Riner		UUCP: !fortune!dsd!riner
	AMPEX Corp
	Redwood City, CA.