[sdiy] noise pickup suggestions?

[Gerald Stevens]

Hello,

I built a nice dual ADSR module based on the ASM-1 ADSR : schematic here:

http://www.elby-designs.com/asm-1/adsr/adsr-asm1-cct.pdf

picture here (irrelevant, but nifty)

http://electro-music.com/forum/viewtopic.php?t=16233&highlight=dual+adsr+trade&start=250

The nice thing about this form of ADSR is that you can monitor the
analog switches and get triggers out from the decay and release stages
- handy for chaining together envelopes to create complex envelopes.
Also handy for generating delays.

When the envelope is set for short attack and decay, (i.e. snappy
envelopes) my CGS tube VCA picks up noise through the power supply and
makes popping noises.

It seems like the ASM-2 revision may have dealt with this problem by
dedicating separate AGND and DGND circuits.

http://www.elby-designs.com/asm-2/adsr/adsr2-asm2-cct.pdf

My Blacet power supplies probably aren't amenable to this, and I don't
want to redesign the board.  I'm hoping some clever capacitor dropping
might help.

Two questions:

Should I replace the two 10uF 25V caps on the +-15V inputs with
something larger?  What about running a small cap across the same
power leads to let high frequency noise run to ground?

Should I drop a bunch of nF caps from the +-15V Vcc and  Vee inputs on
the 4053's to ground?  I seem to recall that this could help, though
I'm not sure - it might hurt

What about ferrite beads?  My recollection about these is that they'll
block RF nicely, but lower audible stuff will weasel through.

Any suggestions (other than using a separate power supply, which will
I reserve as a last resort) would be much appreciated.

-gerald