[sdiy] Module power - regulated or filtered (passively)?

[Pete Hartman]

On Tue, Jan 7, 2020 at 10:16 PM Quincas Moreira <quincas at gmail.com> wrote:

> Yes, Yusynth and MFOS modules for example use such protection, and I can
> vouch that it does work, as I've burned a few myself when starting out due
> to inverted opamps. The 10R burned before anything else could be damaged on
> the boards. Erica Synths uses resetable fuses for the same purpose and it's
> a better solution since you don't then have to replace the fuse, it just
> interrupts the flow when excessive current is drawn, but doesn't burn out.
>

"Usually".  I've seen it done :-D   By others in this particular case.  The
board was in such bad shape by the time I saw it, I have no idea what they
did to melt the PTC fuse.

The problem I have with the 10R solution is that if it's a VCO and it draws
any significant current *and* uses the rails for reference (which a lot of
those using this method seem to do), it can lead to an unstable VCO.  It
doesn't take much to be audible, and I have encountered this with "real"
designs in the DIY space.

Pete
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