Old synth & variac, wasRe: FGTH, was Re: [sdiy] "Foot pedal"?!

[Paul Perry]

----- Original Message ----- 
From: "john mahoney"
> Should a keyboard that's been asleep for 2 decades be brought back up with
a
> variac?
> --
I would think not, because the rectifiers & main caps are driving
regulators, and
the system as a whole isn't designed to run with an odd input.
In fact, with the input under-run, you will be sending odd unsmoothed
voltages to various parts,
with possible problems with analog and digital circuit interactions
(sometimes stuff is designed
in such a way that it needs some power rails to be always higher than
another, or to reach
operting voltage in a particular order).

I hope that someone with more experience than I have will answer as well,
but personally
I don't think it is ever a good idea to run anything outside its design
specs, even on the low
side.

paul perry (Frostwave analog fx) Melbourne Australia