7 to 5 midi pin. Will this do damage?

I think this will be fine but wanted to check the experts. I wired in a G Lab M2L midi looper to put my Empress Compressor only on clean channel and not the others. So I have 5 pin cable out of midi mate into the M2L  5 pin thru to a 5 pin coupler. Problem is my cable out of the amp is a 5-7 pin cable. In order for it to work I need to run 5 pin on pedalboard side and 7 pin into the amp. So that means te gm36 will be supplying phantom on 6 and 7, but nothing on the other side (there is a barrel jack on that side if I was going to plug the power into it, you know the type). So I think it will be fine. What say you?

I am still getting my head around your setup here, I'm not an expert with pedal setups as some of the guys out there are. I'm not sure what you mean when you say "In order for it to work I need to run 5 pin on pedalboard side and 7 pin into the amp." That sounds like you are planning on having a dedicated cable with a 5 pin on one end and a 7 pin on the other. The amp doesn't insist on having all 7 pins of its socket used. That phantom power midi socket takes either all 7 pins to power the FSM432 or only 5 pins to simply function with a separate wallwart FSM432 power supply. The fact that there is nothing connecting on pins 6 and 7 at the amp is irrelevant. Is that what you meant?

I think BB is correct.  6 & 7 are phantom power for the LED display only.  Pins 1 through 5 are standard midi.  But, your mileage may vary since I do not have the manuals in front of me. I think it talks about this in the manual that goes along with the pedal.  Or, it may be discussed with the amp in its manual.  It talks about it somewhere.  

Thanks gents - yes, I'm quite confusing in my post - apologies. I'm connecting the 7 pin side to the amp - so it's carrying phantom - however the other end of the cable at the board is 5 pin with a barrel jack. So the GM is supplying phantom to nowhere, but the midi is still going over pins 1-5 so I think I'm good.

Yup! Very clear description of what you're doing there John. It won't hurt at all that the phantom power lines are going nowhere, (as long as they actually DO go nowhere of course ). Remember, you could just do this with a straight 5 - 5 midi cable. The amp won't even know that you have no pins 6 and 7 to insert. You don't need a custom 7 - 5 cable at all.

Phantom power is only for the display? I hadn't twigged to that Hwy. That's interesting.

I'm not 100% sure about the voltage for the display using 6 & 7. Just a guess. That's how I would do it.