Help ! Huge Volume Drop !?!?!?

I had a huge volume drop at church yesterday, but I ended up playing last night and it didn't do it again. I thought it was fine, but it ended up happening today. I'm sure it's not my guitar cord or the cord going to the amp. It can't be a patch cable either because I plugged into every pedal individualy and my volume still dropped. I plugged straight into the amp, and it worked fine. Could my power supply be causing the problem ? It doesn't drop instantly, it happens out of nowhere in the middle of playing. My chain goes like this-

Boss TU-3, Dunlop GCB-95, Boss DF-2, Keeley SD-1, Boss CE-2, Boss DD-3, MXR Carbon Copy

It's all powered by a Dunlop DC Brick except the DD-3 wich runs on it's own adapter. I realy think it's my power supply, but I've never heard of this problem with one.

The wall wart to the Brick maybe going bad. But i wouldn't discount the patch cables. If it's a loose solder joint, it can go anytime or be fine for a long time. Take each patch cable and test them out individually, shaking then vigorously.