This was discussed earlier, but I can't find the thread. I think
someone said, that Yamaha BC2 breath controller could be connected
directly to a modular, although the voltage levels would not be optimal.

I have BC3, which I can connect via MIDI using SY99 synth between. I
would like to try analog connection. BC3 has stereo miniplug and
connecting that directly to modular does nothing. Can you help

Best regards
Jari Jokinen