Doepfer

Hi Neil,

> what are they?
> 
> There are two unconnected pins on the PCB. What's up
> with that?

That sounds like jumper 'JP2' at the top edge of the board: when the 
little jumper is present, it shorts out capacitor C1, which allows the 
module to process low-frequency, control-type voltages; when not there 
the module will only work with higher-frequency, audio-type of signals. 
I would normally expect it to be there unless the user has a specific 
reason for wanting to take the DC level out of the signal input.

Hope that helps.

Tim