Strange hum on DoubleD

[RDV]

I built this(DoubleD) last year and sort of gave up on it. It has a crazy hum that occurs(on both channels) when either gain is turned below about 10:00 and above 11:00. I've rebiased the JFET in front to half the supply with a trimpot, but that only helped the overall sound and sustain. I've also gone through the circuit and checked component values and connections, but the cause has eluded me. There's only a small range on the high gain(Bounce) channel that can be dialed in without this hum occuring. I have also tried different chips.

Any Suggestions where to look next would be greatly appreciated.

RDV

[RDV]

It seems a bit like a ground loop noise that occurs when the gain pots are shunted to ground. HHMMMM.
RDV