I have a 100 watt all tube fender twin amp and i use a jeckyll and hyde ultimate overdrive pedal which i power with a 9 volt adaptor and i play a gibson les paul standard. i use a monster cable and some other cheap cable to connect the pedal to the amp. i put my amp about two feet from my basement wall and is located next to another cheap behringer guitar amp which i use for my shure mic. now the problem is that when i crank the volume up past about 3, the sound starts to get really disgusting and the bass seems a lot higher and the noise feels like it is cutting in and out. i dont know if this is a problem with my cheap cable which ive had for about 2 years or if its a problem with my pedal which i have beaten the **** out of for about a year or two or if its a problem with my amp because it is a fender twin and people usually dont use fenders for distortion and overdrive sounds. so what do u think the problem is?
Try and narrow down the problem, try it with a different cable, try it without your pedal (the amp on it's own)
Yes try everything you can, and if it seems to be the amp might want to get the tubes checked out, not saying to go out and buy brand new tubes yet but try to check them maybe. This doesn't seem like a tube problem though, but it never hurts to check.
i get the same thing when i use my marshall jackhammer into my Peavey Bandit, I use decent leads and such and its the pedal i know that much. i'm not too sure how to sort it out though.