It wasn't going to be combined but I think it would have been too long so... Years ago I bought a professional steel players pedal board rig and it was made by the old old valley arts shop. It had some really nice pedals, a couple being custom-made by valley arts like a nice Fuzz Face, and a dual mono or stereo loop, but first thing I noticed was the power supply besides also being custom made utilized the fact that the pedals are already grounded together by the quarter inch jacks, then they ran the 9 or 18 volts out to each pedal with a single wire and then injected it with stereo plugs at each input... It was hand soldered Bill Lawrence cable, with a single thin piece of black wire, with nine/18 volts cable tied, and casually wrapped around each, then into stereo 90° quarter inch plugs. Each internal battery clip was set for continuity with a 'sacrificial' clip shorted to itself-positive to negative then taped over-I do the same with bulk clips with a soldered wire connecting them. What I found tonight was, just using a factory 9 volt 500 milliamp supply as comes with beat buddy or hotone multi effect, I had one Daisy chained to a Matthew's effects architect full tone full drive boss super overdrive boss rt20 rotary and the chicken salad univibe clone. It was relatively quiet with obviously some noise with the distortions kicked on but with all of them off and just cycling the two rotaries I was getting noise which completely went away when I cut the ground and just ran positive out to the boss rotary. Obviously I was getting a loop, and I'm not sure if I could have changed them around, that is to say running the 9 volts (no ground) to one of the other pedals, but it sure helped in this case and might help to give a few ideas to someone else. In this case I'm running a single 9 volt feed to the outboard Jack of the Roland rt20 with ground being supplied/shared to all through the quarter inch jacks. The final picture is just one of the old cables I got from the valley arts board and next to it is a 9-volt clip with a wire between positive and negative. One interesting little thing is the super overdrive I have won't play with power being supplied to the outside Jack unless there's a battery in it or ostensibly I guess a clip tying the positive and negative together which sort of is counterintuitive to me... Could it be reverse polarity diode... I can build them but I never said I understand everything about them! Ha!