> Thanks for the info Dieter - EMIS are wiring them for me.
> Can I just ask you -
> Do I need to provide power for both the mixer modules, of just the
> one that has the IC remaining installed

Both modules have to be powered because of the common GND. If GND is wired
too between both modules only the module with the OpAmp IC has to be
connected to the bus board.

Best wishes
Dieter Doepfer