I’m having a similar issue with my B9 that it produces considerable amounts what seems like 60 Hz hum. I generally isolate it from the rest of my pedal chain using an ABY splitter and I specifically power it with separate EHX “wall-wart” and not the main power-brick for the rest of the pedals. The “guitar” signal is sent to my guitar amp amp the “B9” signal goes to the PA or to a separate amp. So, in principle (at least) the two signals should be isolated.

HOWEVER, I get noise and bleed-through of the B9 in my guitar signal, which is totally eliminated by unplugging the power to the B9.

Everything seems to be OK when used as a stand-alone. So, there’s either a grounding problem or perhaps RF interference between the B9 and the rest of my guitar rig.

Any help or suggestions in sorting this out will be greatly appreciated. I really enjoy using the B9, it adds a really interesting dimension to our music that catches listeners off guard.