Switch array (crosspoint) and DC biasing of audio signal
The circuit below will provide DC bias for inputs to the switch, and remove DC bias on the outputs.







simulate this circuit &ndash; Schematic created using CircuitLab

"in" is any input to the switch.  "out" is any output from the switch.  The input bias circuit has a corner frequency below 1 Hz.  It will pass frequencies above that.  The output bias will have a corner frequency that depends on the input impedance of the next device, but will likely be 10k+ so should be ok.

Each input to the switch will need the input biasing below, whether it comes from a guitar, effects pedal, or other device.  Each output from the switch will need the series capacitor to prevent the bias from getting to the next pedal, amp, or other device.

The capacitors should be ceramic type, which have no DC voltage polarity.  X7R type ceramic has been suggested.