Xref: utzoo rec.audio:7346 sci.electronics:3355
Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!mailrus!tut.cis.ohio-state.edu!rutgers!okstate!chris
From: chris@a.cs.okstate.edu (Chris Schuermann)
Newsgroups: rec.audio,sci.electronics
Subject: Re: Homebrew audio equipment
Message-ID: <3727@okstate.UUCP>
Date: 19 Jul 88 13:38:32 GMT
References: <1075@gethen.UUCP>
Organization: Oklahoma State Univ., Stillwater
Lines: 43

From article <1075@gethen.UUCP>, by abostick@gethen.UUCP (Alan Bostick):
> Because I fundamentally distrust snake-oil sellers in both the
> dealerships and the magazines, I am interested in building my own audio
> equipment.  In particular, I am thinking of starting out with a stereo
> amplifier, capable of feeding at least 25 W per channel into 8 ohm
> speakers.  I am interested in making a QUALITY piece of equipment, not
> 
> What sort of test equipment would be useful for such a project (beyond
> the obvious VOM, signal generator, and oscilloscope?
> 
> "DIY!"				Alan Bostick
> --Peter Gabriel			ucbvax!unisoft!gethen!abostick

There are some VERY good amps available out there, but I gather that
you are more interested in building this "for the sake of doing it
yourself"
First, start out by finding yourself two GOOD transformers.  Center tap
with +- 50Volt or so.  Add filtering caps and some BIG electrolytics
to give you a really solid power supply.  I would recomend going with
a class B type amp for simplicity and greater power! I have built
one using 8 stages of push-pull mosfets  (They were some TO3 *case
Hitachi units).  I think my amp is capable of putting out over 1Kw
per channel, but I couldn't find large enough transformers to do the
main amp section justice :-).  Ther are some audio magazines that have
had artices discussing how to build clean lo-noise front ends for audio
amps.  I would look in your local library to find out more.  I WOULD
recomend building a higher power than 25W amp .  If you listen to CDs
at all, that 25W will run out all too quickly. The power supply seems
to be the hardest part. Getting good high curre&nt transformers is 
expensive.  My amp needed +- 140 Volt to put out full power, but I
had to settle for 70V.

As for test equipment, I found that a 'pink" noise' generator and 
spectrum analyzer came in handy also.

Good luck! Building your own audio stuff is really fun and rewarding!
( and also a headache sometimes :-)


-- 
Chris Schuermann
Unemployed...

     chris@a.cs.okstate.edu