Midi 1U / uMidi issues

Eurorack
#1

I just got the new Midi 1U module… very cool and I’m looking forward to the expander as well, but I’m running into a weird issue.

I already had the old uMidi 1U module, so I’ve got each in a separate 7U case and I run a DIN cable from one to the other via the THRU port.

I’m mostly using my OP-Z (with oplab module) with it so I’m only using MIDI DIN cables (USB seems to always end in headaches). I’ve got the Midi 1U configured in dual mode with the first voice on channel 7 (OP-Z Arpeggio track) and the second voice on channel 6 (OP-Z lead track). The uMidi is on channel 5 (OP-Z bass track).

So occasionally I hear the arpeggio track just stop playing. I’ll notice that the LED is held green when this happens. When arpeggio track drops, the bass on the uMidi is also effected strangely… sounds kind of like its skipping some notes in the sequence, but also inserting random, out-of-rhythm notes (a high E) in weird bursts.

I wasn’t sure if this was an issue with the OP-Z or the Midi 1U stuff, so I ran the MIDI out from OP-Z to my Model:Cycles before sending it along to the modular, hard panned the modular left and the cycles right and sent the bass and arpeggio Midi to two channels of Cycles. The Cycles never misses a note when the modular stuff is dropping out or playing weird bursts. It also doesn’t seem to matter which case/module gets the Midi first… happens either way.

It could be that there is something funky with the OP-Z Arpeggio track… before I got the new Midi 1U, I have had some issues w/ OP-Z and uMidi’s CLK output. I found that sometimes when switching patterns on the OP-Z, and especially to an empty pattern, it would make the CLK division jump to something crazy high. I also found it would do this when I’d be changing parameters of the arpeggiator track. I ended up just giving up on using the CLK output because the 1/16th output was rock solid.

Makes me think that maybe there is some kind of weird message going out with the OP-Z Arpeggio track that the Intellijel Midi devices are reacting strangely to? That’s the best I’ve got. Sorry for the long-winded post, but I would love to find a way to solve this!

#2

While this isn’t documented in the manual, MIDI CC16 is able to change the clock division setting. Is it possible that your OP-Z is sending a message on this channel that’s affecting your division setting?

#3

Hmm… so looking at the OP-Z midi spec on this page, it looks like CC16 is used for setting the volume of a track. Does uMidi respond to CC16 on any channel or is it a specific one? If I’ve changed the volume of a track in a pattern and switch to an empty one where that track has the default value for volume, that would trigger a CC16 message so that makes sense and seems like a good explanation for why the CLK output on that module was behaving erratically.

Any ideas about the issue of glitching/missed notes?

#4

Can you tell if there’s any setting or condition that causes the track to hang or skip notes? Does it happen when you increase the tempo or gate length of the notes or is it after a certain amount of time?

#5

It just seems to happen sporadically/randomly. I was letting a sequence just run on its own for a while without touching anything.