BYOC Analog Chorus pulsing noise HELP!

[rosssurf]

I have built a BYOC analog chorus with no substitutions. It is battery powered only, and seems to work fine except when I run it into a distortion pedal. It seems to make a whistling-Popping sound. Strangely enough this popping sound is much less apparent when the "depth" is turned fully clockwise. When I reduce the "depth" dial back to  90% of it's maximum or less the popping/whistling comes back rather loud.  If the "rate" is just a little slower that max or more the sound a popping noise with no "whistle' sound .

How can I stop or minimize this?

FYI the distorion pedal is a BSIAB i built that works fine and is powered my a "Signal Flex" ps-9

Sorry for the convoluted explanation of my problem. I hope someone can understand enough to offer some help. I am learning 

Any advice is appreciated

[R.G.]

What does the BYOC support email/forum say?

[gena_p1]

power both from separate batteries, for test

[AnnaHSGW]

I've read some posts at the BYOC forum about this (check their Chorus board) and some have suggested that the power wire may be to close to another wire and that is what is making the pulsing sound.

[gena_p1]

Pwr and Gnd wires are everywhere good, and slow down noise.

Popping  usually mean bad isolation of Schmidt trigger, too long wires to potentiometers, plastic box without grounding (pots need to be grounded too)