[sdiy] SH101 MIDI Mod problem

[Dan Gendreau]

Before you dig into hardware issues, try shortening your notes a few ticks
and see what happens...

IIRC the sh101 uses an auto-porta circuit that detects legato notes via CV
control. If there is a gap between two notes, it disables portamento for the
second note.

Now the question here is how long must this gap be before the sh101
considers it a 'gap'?

If your midi sequencer is playing quarter notes back to back for example,
without legato the gap is likely to be 1ms (the time it takes for 3 midi
bytes to transmit between note-off and note-on).

Perhaps the SH101 auto-porta sensing circuit is only partially shutting off
because 1ms is too short?

Another possible cause would be if the Gate CV switches on before the pitch
CV settles to the new note. In this case you might be able to delay the gate
slightly using an RC circuit...

-Dan G.