In thinking about this I reckon I can do away with the input stage (or possibly just pop a big capacitor in there for DC separation) as the preamp I built should be suitable here.

Which means I just need something on the output from the Kaoss pad - as it is just feeding in via a normal guitar input to either an amp or a stereo DI I was thinking I don't really need to worry about rolloff, as both of these options have input buffers, so I really just need DC separation again.

Does anyone know enough about this to suggest capacitance/resistance values which would be suitable (I'm thinking 10uF and a 100k potentiometer for the volume control - seem reasonable?)