Just when I thought :( ......... MC6 MKII to Iridium via Midi TRS Causes Hum .... suggestions (?)

Hi all again !

All working fine except:-

→ I’m using a nice high end TRS to TRS between the MC6 and the Iridium and there is a hum / ground loop.

→ I de-soldered the ground at the Iridium end - didn’t fix anything

But … if I pull out and re-insert the TRS at either end, the Hum disappears but immediately comes back as soon as I hit a FSW on the MC6 ??

Tried different Midi Modes on the MC6 - got rid of the hum but wouldn’t then switch presets ??

Any help much appreciated.

Is it worth trying to de-solder the Ring Connection too ?

I really don’t want to spend $40 on the Strymon Midi to TRS lead :frowning:


It sounds like there’s something else causing the grounding issue that’s being exacerbated by the connection to the Iridium. How are all the pedals including MC6 being powered? is it an isolated power supply or 1spot?

It’s unlikely but have you checked the TRS switches are in the right place to support the Strymon connectivity?

Hi Hawkins76 !

Damn it … you got it in one :slight_smile:

TRS Cable is in the right spot.

Everything was being powered off a 9v 2000ma supply with a 7 x 9v-plug-loom running off it … I couldn’t see why that would be an issue. … but it was/is.

Running the Iridium off its own 9v Power Supply and everything else of its own 9v Power Supply and … bam … zero / no hum or ground loop sound of any kind :slight_smile:

A bit annoying having to run 2 x 9v Supplies but at least I didn’t spend the +$40 on the Strymon Midi to TRS and run it with the 1 x 9v supply and still have the same problem :slight_smile:

Many thanks,

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Glad you managed to resolve the issue.

Most pedals will benefit from an isolated power supply like the Strymon Zuma or Cioks DC7 which help avoid ground loops and interference.

That’s the problem with pedal power… you’ll probably be fine with a multi outlet non-isolated power supply… until one day you’re not!

The classic one in my experience is “the guitarist adds their first digital pedal… and then it makes horrible noises”

General rule of thumb: daisy-chaining power to analogue pedals is often okay, but try to avoid daisy-chaining power to digital pedals.

(Plenty of people ignore the rule with no problems, but if a noise problem does come up and you are daisy-chaining everything, well…)