Okay, I have a 100 watt tube Krank Revolution Half Stack. Now when I am on clear setting it's perfect, I switch to my distortion channels, and it's bloody terrible, so much feedback I get in the background, It's not the patch cords, and the tubes are brand new... or so they tell me... Any suggestions?

Also I have a line 6 floor pod. Brand new, whenever I use that pedal... It gives me crazy amounts of distortion that should not be there, and it sounds horrendous.
It's probably just the amp. A lot of high-gain amps feedback a lot like that and need a noise suppressor to calm them down.

It could also be a preamp tube gone microphonic.

Try turning the gain down and standing further away from it.
Quote by Dave_Mc
I've had tube amps for a while now, but never actually had any go down on me
Quote by jj1565
maybe you're not saying the right things? an amp likes to know you care.

You could be feeding it to much signal. Turn your guitar down some and check your volume settings on the POD.