MIDI2CV DIY problem

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drip.feed
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Joined: Thu Sep 15, 2011 10:05 am
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MIDI2CV DIY problem

Post by drip.feed » Mon Dec 23, 2013 4:10 pm

I have DIY'd this excellent module but I have come up against a problem I just can't diagnose.

In Poly 1 and Poly 4 modes only the CV1 and GATE1 sockets output any voltage. The other 3 CV/GATE sockets don't output anything when I change the MIDI channel to 2, 3 or 4.

I stuck a meter across the pins on the middle board (the row marked CV1 CV2 ... SYNC LED+) and again, only CV1 was outputting a voltage I would expect. The other CVs wavered around a few millivolts if I remember correctly. So the problem isn't with socket connections.

I have reflowed all suspect joints in case there was a dry one. But because of the symptoms, I think there is something more sinister going on. Have I blown an IC maybe? :despair:
Dripfeed

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drip.feed
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Joined: Thu Sep 15, 2011 10:05 am
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Post by drip.feed » Fri Dec 27, 2013 10:32 am

I may have been barking up the wrong tree this whole damn time. :bang:
  • Mono mode works fine.
  • Poly 1 mode works fine!
  • Poly 4 mode does not do what I expect, so it may be working for all I know!
Poly 1 mode
4 note chord sent on MIDI channel 1 = all blue LEDs light up when they should; the correct pitches and gates come out of sockets A - D.
4 mono riffs, each sent on a different MIDI channel (i.e. multi-timbral mode) = all blue LEDs light up when they should; the correct pitches and gates come out of sockets A - D.

Poly 4 mode
4 mono riffs each sent on a different MIDI channel (i.e. multi-timbral mode) = only pitch and gate come out of sockets A.
1 mono riff, sent on channel 1, but riff has overlapping notes to force legato = CV-A and GATE-A work as expected. CV-B and GATE-B output pitch/duration for the overlapped channel 1 notes only.

Is that how Poly 4 is meant to work?
:hmm:
Dripfeed

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