Impossible MIDI issue driving me nuts

So I have this bizarre situation that is really frustrating me and I wonder if anyone has ever seen the same…

The scenario: I connect the MIDI out port on my Digitone to the MIDI in on my drum machine (Alesis SR-18). I enable clock out and set the output ports to MIDI. I switch to a MIDI track and enable it to send on channel 12. On the SR-18 I enable drum in and clock in and set it to channel 12.

The problem: the SR-18 doesn’t respond to any midi notes or clock signal. Nothing happens at all.

The twist: if I connect the MIDI out (same cable) to the in of my other synth (MS2000R) and then connect the Thru jack on it to the SR-18, bam, the magic happens. The drum machine responds to notes and clock.

With everything working I swap the cable back to be directly to the SR-18… No dice.

How is this possible??? The MIDI thru should be an identical copy of the data being sent. The MS2000R has no complex MIDI mapping or anything. It can’t be a bad cable because then it wouldn’t work with the thru routing.

I feel like I’m missing something here but I don’t see it and it’s driving me crazy.

Thru is an exact copy of in but it’s not necessarily on the same channel. Sorry but that is the first thing to check even if you probably already sextuple checked that.

Have you something that can monitor midi, these little boxes have proven to be invaluable in troubleshooting such issues.

I agree it makes sense that it would be a channel issue, but I have everything set to specific channels and not ‘all’, but I’ll see if there is any difference or options for receiving on all channels. I don’t understand why it wouldn’t receive on the correct channel directly but it will from the thru.

Sadly I don’t have any other midi monitors, the thru port on the ms2000r has no config options that I can see so it should be working in the default expectations…

I doubt that there is a problem with the MIDI messages being generated.

However, it can happen that there are hardware mismatches between units; in this case the MS2000R may be well enough specified that it can effectively act as a buffer between the two units.

You are fortunate in having this workaround to the problem available. To nail down the problem further it would require you to try different cables and different synths to further establish the exact cause of the problem.

Sadly I don’t have much other MIDI gear… I have a MIDI enabled loop pedal, and my interfaces. I can do some tests with that. But I’m not sure how to troubleshoot the DN + SR-18 alone, besides trying different cables. Seems odd that there would be such a major mismatch between two fairly modern pieces of gear.