[sdiy] Variacs and modular synths

[harrybissell]

If you wanted to play with the supply... it would be better to make
a variable DC power supply that puts out the needed voltages, rather
than use a variac.

Probably you could make the main filter caps too small, and have
switches
to add more or less capacitance to get the 'growly' sound of 60Hz (more
likely
120Hz) modulating everything via the power supply ripple.

WELL designed modules may still disappoint... it the circuits use stable
on-card reference sources... the damn things might still work correctly.
That would be my goal in designing a module :^P

Jay is dead right about switchers... and that could go double for units
with displays, or CPUs etc.

Of course as Ian Pace of Deep Purple once said "I bought it I'll bloody
well boot it !"

H^) harry

Jay Schwichtenberg wrote:
> 
> Daryl,
> 
> I wouldn't do this to anything that has a switching power supply or digital
> gear. Good chance newer digital gear will have a switcher in it.
> 
> Linear power supplies can probably survive. Switchers are pretty complicated
> relative to the linear ones and are tricky to design even today with all the
> new chips and tools. If they aren't designed right or cheaped out then they
> can do some nasty things. I've probably seen more of these blow up than any
> other type circuit. In a couple of cases quite dramaticly.
> 
> Have fun and just say no to letting the smoke out of chips.
> Jay
> 
> -----Original Message-----
> From: owner-synth-diy at dropmix.xs4all.nl
> [mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of daryl groetsch
> Sent: Wednesday, January 04, 2006 9:28 AM
> To: synth-diy
> Subject: [sdiy] Variacs and modular synths
> 
> I'm picking up a variac from a friend, going to wire
> it up today. i want to experiment with slowly powering
> up and powering down synth modules (and other stuff
> too). i know my Blacet power supplies will try to keep
> a steady voltage going to the modules, but i still
> want to see what happens at lower volages. i like the
> sound of turning off and on my synth and want to
> control that--a switch just isn't enough. must admit i
> was inspired by that NPR program on the Barrons and
> their soundtrack for Forbidden Planet. they did this
> and described it as something like bringing and taking
> away life from the circuit.
> 
> so, if i keep it below 120 volts, i shouldn't run any
> risk of damaging anything, right? anyone done similar
> experiments?
> 
> thanks a lot,
> Daryl
> 
> http://synthnoise.com/
> 
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