Midi Noise after adding MC8 and ML5

New Mornigstar user here. Great stuff, very intuitive so far. I have issues on a new pedalboard build. All audio working fine with one exception. Noise. I believe it to be midi noise. I run an RJM PBC10, Morningstar MC8, ML5, Strymon Timeline, Mobius, and Big Sky.
Midi loop is as follows: PBC>MC8>ML5>Mobius>Timeline>Big Sky>PBC.
Previously, i ran just the PBC and the 3 strymons with no noise. Now, i have added the MC8 and ML5 and Noise. All pedals are adequately and discreetly powered by Zuma, Ojia R30 or 1 of 2 other Ojai’s. Everything is isolated. If i unplug 1 midi connection, the rig is silent. When i plug it back in, constant ticking and slow high pitched oscillation. Any ideas?

Are you plugged in to the USB for computer editing? That always creates a midi ground loop for me.

no. Only when laptop is plugged into power supply does this cause issues. I unplugged the usb completely and issue remained.

I might start by adding in each pedal one by one to isolate the culprit.

USB or not, if the noise goes away when you put the laptop on battery and unplug it, there’s likely a ground loop from the laptop.

Can you connect the laptop to the the 5 pin midi din for the PC (and not the omniport)? Not sure the omniports are opto-isolated.

Even better, have no wires from the PC. If you can connect from the PC via Bluetooth that airgap would prevent any ground loops (e.g., add a widi jack to the MC8)

Some info here: https://morningstarengineering.atlassian.net/wiki/spaces/MMS/pages/689078273/There+is+MIDI+Noise+in+my+Audio+signal

But I don’t think the lack of opto-isolator is the issue. When you mentioned you unplugged 1 midi connection, which connection is it?

Yes, that is what I would recommend as well.

When i unplug the mc8 end of run from pbc to mc8, or mc8 end of mc8 to ml5, or recieving end of ml5.

Does the ML5 have an opto-isolator?

I will try that this evening and post the outcome.

Yes it does. Almost all 5 pin MIDI Inputs would follow the MIDI spec and be built with an opto-isolator. So far I haven’t come across one that hasn’t. Usually those without are TRS MIDI Inputs that also try to implement other functions like Exp In.

PBC 10 AND an ML5?? How many pedals are on your board? (pic please)

Yeah. 17 actually. I added the ml5 for stuff i wanted pre buffer. Fuzz, wah, univibe and a couple boosts. The mc8 i added after looking a pianomans rig and i use it to get to pbc pages quick and manage presets on the fly live for the 3 strymons.


Oh man. Your board is just… wow. I’m speechless.

Edit: it’s got a gooseneck light?!?! :facepunch:t3::facepunch:t3::facepunch:t3::facepunch:t3::facepunch:t3::facepunch:t3::facepunch:t3::facepunch:t3::facepunch:t3::facepunch:t3::facepunch:t3:

Impressive cabling work.
I understand your disappointment, all this work then … some hum somewhere :frowning:

Actually, it seems as i expected. As long as i dont use the mc8 internal midi clock, its fine.

My issue was Midi noise with my Strymon - they don’t isolate (the Iridium in my case) the Midi with an opto-isolator, so my workaround (which is in one or more of my threads) was to create a TRS cable with the ground NC on the Strymon end only. It was obvious that the high-pitch was caused by that one cable alone. Disappointing to say the least, but at least I was able to figure it out after doing a little research, as I’d assumed it was a ground loop issue.

Tim, thanks for the reply. Since my post i have for sure confirmed its midi clock noise. Here is my midi chain:
PBC10 out>MC8 controller>ML5 loop box>Mobius>timeline>big sky>PBC.

Are you saying if i nip the ground in the cable between the ML5 and my first strymon it will fix this?

Thank you

The Strymon is not MIDI compliant to grounding spec, so YES, it should work. You experiment by simply un-soldering the GROUND on the TRS connector going into the Strymon MIDI IN. I’d imagine it would be the same on the standard 5-pin DIN connector as well. Keeping the ground wire intact also acts as a noise shield throughout the cable.

So after some more testing, i have isolated the issue just to the Strymon Mobius. I run the mobius in PRE/POST mode. If your not familiar, this allows the left in/out to be in front of the amp, and the right in/out to be in the effects loop of amp. Since you have just stated that strymon uses non midi compliant grounding, i would venture to guess my issue is a ground issue at the mobius where multiple ground planes interface. The midi plane, the pre-amp plane, and the effects loop plane. The power is not the issue. I do not believe my RJM PBC isolates between pre and post. I have a buffer at loop 1, a buffer on the send to the amps front end, and another buffer on the return to the amp. But in theory, i could have a ground loop anyway as the mobius pre loop is between buffer 1 and 2, and the post loop is between buffer 2 and 3. I have a ticket started with Strymon on this, but they will likely refer me to their blog entry on noise, which i have already read. I am not going to lift the amp, and my second amp is already isolated through the switcher. I think the solution will be 1 of 3 things:

  1. nip the ground on the audio return cable of the Mobius’ post loop to the switcher.
    2)nip the ground on the midi out cable between the mobius and the timeline.

Does this added info change your approach at all?

Thanks man,