Guitar pedal problems

Don't know if this is related but I recently got one too many pedals for my power source so I got one of those eight plug daisy chains for my one spot plug in. It works great on everything except for my Boss ME-80 multi effects unit which gives a loud hum if placed in the chain. The chord for that one is heavier and probably has a built in ground. So I have to leave that one out and power it by itself. So, my guess is it's a grounding issue.

Disconnect the brick and run everything off batteries. If the noise goes away, you've isolated the problem(s) to the brick and its leads.

Make sure the +/- polarities and voltages sent match from each brick output to each pedal input. Mismatches will result in noise, poor performance, stuff not working, even stuff going up in smoke.

Just making sure ... you do realize adding OD and fuzz and wah to a dirty channel on an amp is going to add hiss, uncontrollable feedback, assorted white noise, etc., no matter what you do? Some of that stuff, even a good noise gate can't shutter it in functional fashion.

Could be the electricity too... Playing in many places, that makes more hum than anything else in my experience...