> Is it possible to couple together two Doepfer A138 mixers to give me eight

inputs

> Anyone know if this is possible
> Richard

No problem. Remove IC1 (TL062/TL082) of the second A-138 and connect the
common inverting inputs of the first OpAmp of both modules (e.g. available
at pin 2 of the TL062/TL082). The output of the second A-138 is no longer
working unless you connect pin 7 of TL062/TL082 (= output of the second
OpAmp) of both modules. In this case you have two outputs with two different
levels available. Attention: warranty will be lost in case that the modules
are still under warranty !

For details please refer to the DIY page (CV mixer with offset function) for
the basic principle of the A-138 circuit.

Best wishes
Dieter Doepfer