Ticking noise when sending MIDI to my ML5

Morningstar Gear ML5
1

Whenever any MIDI message is sent to my ML5 a single brief ticking noise makes its way into my audio signal. It’s relatively quiet, but it’s there.

It’s most notable when sending MIDI clock, where the low pitched tick increases pitch as the clock message frequency increases.

For test purposes, signal chain is:

Guitar → ML5 (all loops disabled, and connected exclusively to MIDI controller) → Amp

ML5 and MIDI Controller both powered by independent outputs from a Cioks DC7.

The ticking noise amplifies with the guitar signal, i.e. If the guitar’s volume is zero then the ticking disappears

Unplugging the MIDI cable of course leads to the noise disappearing.

This post seems to accurately describe my issue
There is MIDI Noise in my Audio signal.

However, it seems to imply that this shouldn’t happen since the ML5 (assumedly) has an optocoupler on MIDI in, as per the spec.

Does it make sense anyway attempting to lift ground between the controller and the ML5?

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2

Hi,
a ground loop is the most likely reason, but not the only one.
I’ve had noise issues, too. Turned out that the issue was that I ran a bunch of midi and audio cables close together beneath my board. The noise disappeared after I’ve cleaned that up.
I’d check first if the midi cable is ok.
Also try to use seperate powersources for both devices. See if the issue persists.

3

Thanks for the suggestion.

I disconnected the controller and instead used MIDI out from my Fireface UFX II, with a different cable, with the clock signal being sent by Logic Pro.
The cable is clear of any audio cables, and the power source is now different.
Unfortunately the same ticking noise is evident.

I guess I’m going to have to try lifting ground, which is a little concerning given that the ML5 is really the only MIDI component connected to the audio signal.
Perhaps there is a fault with the ML5…

4

I just tried lifting ground, unfortunately doesn’t change anything.

If I replace the ML5 with an Eventide H9, there is no noise.

Given that my ML5 is only a month old, I am inclined to believe this may just be a design flaw with the device - the MIDI circuit is somehow coupled with the audio circuit… ?

5

I’d send a mail to morningstar via the contact on the official website to sort things out.

1 Like
6

Please let us know your unit serial number and order number in the email as well, thanks!

1 Like
7

It sounds like a classic case of MIDI-induced noise. Since unplugging the MIDI cable eliminates the issue, a ground loop might be at play. Lifting the ground between the controller and ML5 could be worth a try, or you might want to test with a MIDI isolator.