[sdiy] DC-DC Converters

[WeAreAs1 at aol.com]

In a message dated 3/21/04 11:26:05 AM, harrybissell at prodigy.net writes:

<< They are switching power supplies. The little ones (charge pump type -
no inductors)
can supply only a small current.  Larger ones (with inductors) can
supply large currents.

Electrical noise is an issue - the high frequencies can get into VCOs
etc and cause strange
issues. But there is NO reason to dismiss them out of hand. You may need
to do some
experimenting, and possibly use more sophisticated power filtering
techniques... >>

Indeed, there is no reason to dismiss them out of hand.  Many of our favorite 
music-making machines have switching power supplies, and you'd be very 
hard-pressed to ever hear that the power supply is causing audible artifacts, or 
tuning/stability problems with VCO's.  For instance, everybody's favorite 
polysynth, the Oberheim Xpander.  Almost every professional synth and studio outboard 
effect unit that Yamaha has made since around 1986.  Another *very* popular 
analog synth that contains one of the crappiest little DC-DC converters ever is 
the Roland TB-303.  That didn't seem to stop it from becoming the world's 
most desired oddball "cult" synthesizer, and being used to great effect on 
lterally hundreds (thousands?) of records.  (and please don't try to claim that 
"real" TB-303's get their magic mojo from that little DC-DC circuit...Everybody 
knows the mojo comes from the vinyl carrying case strap.)

Michael Bacich