[sdiy] (OT) Doepfer MIDI-CV oddity

[Colin f]

> As an aside, this is the kind of thing that makes life hard for
> manufacturers-

Yep, that's why I'm so well acquainted with the range of 6N139s...

Another new factor in the MIDI equation is that some PC interfaces drive the
line with a lower voltage supply.
MIDI is a current loop, so in theory you just need to reduce the series
resistors and 3.3v pull up on pin 4 should be no problem.
But if the forward voltage drop on your opto is higher than usual, you might
find the margins of operation sooner than you'd like.

Cheers,
Colin f