[sdiy] digital noise: protoboard vs solder breadboard

[Kenneth Martinez]

Just thought I'd pass this along: while working on my
digitally-controlled analog synth, I've now built the same circuit with
a very similar layout on two solderless "protoboards" and on a group of
solder breadboards...with separate +5V power and separate ground for
digital, and the digital circuits on separate boards from the analog (as
much as possible)...

The volume of the digital noise bleeding into the audio circuits is
significantly lower on the soldered circuit - I can only hear it if I
turn off all VCO waveforms and open up the VCF & VCAs.  I spent some
time working on the protoboard to try to reduce it, and finally decided
to see if switching to a soldered version without all that stray
capacitance would help; sure enough, it did.

I'm gonna keep using the protoboards - they sure are convenient for
quick experimenting - but I'll keep their limitations in mind.