Hello!
today i tried one Zvex box of rock -boost section- based booster with my friends active pickup guitar.He uses his amp's distortion and he needs a booster for a solo section .We used the effects loop for the booster .The problem is that we have a feedback problem even if we go to 2 meters away from the amp.I think to put a resistor from the input jack to the ground or to put in series a resistor to the input jack to reduce the power of the pickups.
Also until now i can't measure(and understand) the input-output impedance and i don't know how does this affects the pedal .
I would appreciate if you can help me !