@Den
You're welcome. If you're handy with a soldering iron it's an easy build. I originally made my power injection 'MIDI' cable years ago when I had the Fractal Ultra and MIDIMate controller so, when I got the FM3, I still had the connectors in my bag of electronics parts. Here's a run down on what I used:
The cable mount MIDI connectors came from REDCO Audio. Pics of today's pricing are included.
5 pin:
https://www.redco.com/Rean-Neutrik-NYS322.html
7 pin:
https://www.redco.com/Rean-Neutrik-NYS323.html
The 'cable' I used is a CAT5 ethernet cable.
My cable is short - only 2 feet (0.6m for the metric guys) - so the voltage drop on the 24AWG CAT5 single conductor for a 1 amp rating is only 0.1 volts. I have not measured how much the MC6 draws, but I'm sure it's pretty small (even if it drew 250mA, the drop would only be .02 V). Needless to say, for my needs the CAT5 24AWG single conductor is just fine.
Only 4 pins of the 5 pin end of the MIDI cable are needed, so technically, I could have 'doubled up' my power wires and used two conductors for the positive and two conductors for the negative. That would have utilized all 8 conductors in the CAT5 cable - 4 for the MIDI and 4 (2x2) for the phantom power.
Here's a link to a voltage drop calculator in case you're curious:
https://www.calculator.net/voltage-drop-calculator.html
The XLR end is from some parts I salvaged from defunct balancing transformers (the infamous ARCHER/Radio Shack 274-017 - loved them). In my build, I decided to fore-go the full blown male XLR housing because that would stand off from the back of the FM3 too far for my tastes. Instead, I just soldered my two conductors to the connector and heat shrunk a 'cover' over the conductors.
The 5 pin MIDI connector is at the FM3 end of the cable - and obviously, the 7 pin on the MC6 end.
Maybe others will find this modification useful.