• Zoom 9002 mixer

When I plug my guitar into a Zoom 9002 then into the input of my amp, the Zoom cuts the bottom end. This circuit is based on an effects loop designed by Kevin O'Connor, and either through mixing in some of the original guitar signal, or through better impedance matching, restores most of the tone.

The footswitch allows the Zoom signal to be cut in or out.

It needs a bipolar power supply. If you want to power it from a 9V battery, the circuit above the schematic is needed.

(updated URL for Kevin at London Power)