The gig went great! 50 minute set!! Didn't use the MP1 though. Used the Peavey Rockmaster instead.
Before I left for the gig, I tested the MP1 a little bit. I plugged into the MP1, and only the MP1. I connected this to my power amps. So it was
guitar > MP1 > Amp > cabs
(usually it's this guitar > Boss GT5 > Boss send to MP1 > MP1 out to Boss Return > Boss Out > Amp > cabs)
Still noise. Albeit different than when it's connected to my FX pedal (in the loop). I couldn't quite tell if it was worse than when it was in the FX pedla loop or not.
So I don't think the pedal setup is the problem. But of course it will add some extra noise as every device will.
@ Soloist I also checked the front and rear input, no difference in noise from what I can hear.
And for the record I now know I have a V2 as no switch on top.
I never got a chance to test the earth on the transformer.
On a seperate note, I noticed my amps are making more noise these days by themselves, could this be part of the issue? In which case should I switch out the electrolytic caps? The amps are may be a little over ten years old. I didn't remember them humming until a few months ago.