AW: breath controller schematics

[Ingo Debus]

Jeremy Brookes wrote:
> The BC input on the 4-ops could be controlled by a pot. It's 3 pins, one at 5V, one at 0V, a pot across these with a wiper to the remaining pin.

It's the same with the modulation pedal jack. On Yamaha keyboards the
tip is the 5V supply and the ring is the CV input. It can be used for
external CV when it does not exceed 5V.

On Roland keyboards it's the other way round: ring is supply and tip is
input. Since the supply is short-circuit protected and the input has an
internal pull-up, a switch with a mono plug can be connected as well.

Ingo