DIY Amplifiers?

[Don Tillman]

   Date: Mon, 15 Jun 1998 14:15:02 -0500
   From: John Randolph Willey <newton+ at osu.edu>

   I was wondering if anybody has any pointers or advice for somebody
   with a sudden desire to build an amplifier for his synths.  The
   commercially available products just don't seem to trigger any sort
   of primal urge to spend money.

I used to be into amp building, but it turns out that commercially
available amps can be bought for about 1/10th the cost of building one
yourself, and they're robust, reliable, and easily replaceable if
something horrible happens.

Back around 1979 when lots of cheap amps boasted extremely low
distortion specs yet sounded really horrible, there were many
interesting articles in the JAES and Audio Magazine about TIM
distortion, alternative feedback topologies and so forth.

Marshall Leach wrote some the best ones, check out his home page: 
http://www.ee.gatech.edu/users/207/

Also check out the Audio Amateur magazine, lot of construction
articles there.  
http://www.audioxpress.com/

But the real interesting question is, what are you looking for in an
amp that the commercial models don't give you?

   Maybe I'm looking at the wrong amps.  The only ones I like at all
   are some of the Roland models.  (?KC-300?)

Yick.

   Anybody have any recommendations for good keyboard amps, or do you just
   send it through a PA system?  I'd prefer some sort of self-contained combo
   amp without an onboard mixer.  

There isn't that much of a call for such a thing.

It depends so much on your specific situation, but...

Guitar amps won't work; no tweeters, and the tone controls are really
inappropriate for synths.

Typically folks plug directly into the main PA, but for other
applications your own small PA system is the right thing.  I use:
  Mackie 1202 Mixer
  Carver PM300 Power Amp
  EV Sx200 speakers

Simple, cheap, sounds great.

  -- Don