I noticed this a few days ago. When i plug in my 2525H head and run the overdrive channel, there is a very strong loud (sounds like) electrical noise. It goes away when i remove the pedals hooked up into the loop.
Now i run a couple of EQ's, mxr 10band eqs on 18v power and a DD7 delay pedal in the loop. I have checked each pedal individually and also changed the cables used and it doesnt go away.
I also checked if its a power supply issue, i run a t rex fuel tank chameleon that powers all my pedals, the 18v jack i have used a daisy chain to hook up 3 pedals, a Fulltone OCD, and the 2 eq pedals, i checked the power draw on each and it is wayy within the required power that is given out of that 18v socket.
Please help, this is recent, i never had this problem before. I've gigged with this amp on a few occassions too, noithing was noticeable, and with this issue its very noticeable on low volumes as well.