I just replaced all of my power tubes and my preamp tubes, and I'm not sure if the hum was there before I changed everything out. But when I turn the amp to the on position, there's some kind of hum coming from the back of the amp. I think it's the capacitor but I'm not sure because I don't want to get too close to the back of my amp when it's on. Do you guys think it's the capacitors or something else? I'm wondering if it's a grounding issue. Is there something that I can do about it, maybe something for a quick fix?

Thanks in advance!

"The most important thing about music is energy and emotion, not how well you can play. Technique should be a tool to achieve your vision, not the other way around."
-Jeff Tuttle

More guitar, less ultimate-guitar!