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From: wtm@neoucom.UUCP (Bill Mayhew)
Newsgroups: sci.electronics
Subject: Re: high voltage Power Supplies
Message-ID: <637@neoucom.UUCP>
Date: Sat, 25-Jul-87 11:46:57 EDT
Article-I.D.: neoucom.637
Posted: Sat Jul 25 11:46:57 1987
Date-Received: Sun, 26-Jul-87 20:50:17 EDT
References: <1811@ttrdc.UUCP> <100500016@datacube> <628@neoucom.UUCP> <693@sol.ARPA>
Organization: Northeastern Ohio Universities College of Medicine
Lines: 21
Summary: Magic word was audio


The high voltage power supply over kill issue was brought about by
the use of the word, "audio".  From reading net.rec.aduio, I've
learnt that circuits for audio applications must be over designed
by a factor of 5 to 10 in order to convince audiophiles that some
horrible bastardization of the sound is not taking place.

For circuits that require a few mA of current, a switcher supply
isn't too terrible.  Recently, I wanted ~200v at about 25 mA.  I
was able to use a ferrite ring and a couple of power transistors
from my junk box to build a "ringing choke".  The output of this
went into about a 1 uF mylar capacitor after being recitified.  I
used two 0B2 tubes to shunt-regulate the output. The whole mess,
except for the tubes, fit inside of one of those little Radio Shark
aluminum boxes and only weighed about 100 grams.  I resorted to
that since I didn't have any old 60 Hz transformers and big filter
caps laying around.  I followed the design (not really copied) from
one of those big "we publish every basic circuit you can imagine"
type reference books.

Bill