Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!rutgers!ucla-cs!zen!ucbvax!cbosgd!cwruecmp!neoucom!wtm 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