PAiA MIDICV8

[Bob Zimmer]

As promised, here is a followup!

I've completed the assembly and testing of the CV8!  Worked first time!

Ran through all of the diags and everything is good.

Question for someone.  It seems that they have put an open collector
transistor on each output in addition to the buffered CV output.  They call
it an S-Trig (I think that is what Moog used), but it requires a pullup
resistor to work:

                         ----------
                        |         |
                        |  |\     |
                        ---|-\    |
                           |  \___|__________________   CV Output
                           |  /         |
        -------from MUX----|+/          \
                           |/           /33K
                      1/4 TL084         \       C
                                        /   | /------   S-Trig Output
                                        |___|/
                                           B|\ 2N4214
                                            | \>| E
                                                |
                                              -----
                                               ---
                                                -

Does any one have an idea of how to make this S-Trig Output into a useable
gate and trigger output?  Their four voice mode does not provide a trigger
output, only CV and Gate.

The operational modes are:

MODE 1:
        One Voice, outputs: Pitch, Attack Velocity, Release Velocity
                            Pitch Wheel, Mod Wheel, Aftertouch,
                            Gate, Trigger Pulse
MODE 2:
        Two Voice, outputs: Pitch1, Velocity1, Gate1, Pitch2, Velocity2,
                            Gate2, Pitch Wheel, Mod Wheel

MODE 3:
        Four Voice, outputs:Pitch1, Gate1, Pitch2, Gate2, Pitch3, Gate3,
                            Pitch4, Gate4

MODE 4:
        Control Change, outputs MIDI Control Change messages for cc1 to cc8.

MODE 5:
        Analogue Drum, outputs pulses corresponding to notes 24h thru 2Bh.

MODE 6:
        DIN Sync, converts MIDI Real Time messages into control signals.

MODE 7:
        Self-Test, for diagnostics.

MODE 8:
        Channel/Status Test, checks MIDI Channels 1-16 for reception.

As you can see, only Mode 1 will produce a Trigger Signal, the other two
main modes (2&3) do not and would need a circuit mod.

So far, the only mod I've made is to replace the single turn CV Trimmer with
a 15 turn to make it easier & more accurate to adjust.

Appreciate any help you can offer!

Bob

  >=== Bob Zimmer -- Philadelphia PA ===<
  >=== bzimmer at voicenet.com          ===<