Hey Gang, I posted about this hum in my DRRI a while ago and Mike @ KCA suggested trying some tricks with the reverb tank which unfortunately did not work. As a refresher the amp makes a noticable albeit not loud 60 cycle hum with no guitar plugged in and no gain running through the amp. The only control which changes the level of the hum is the reverb knob. Perhaps on a club stage this would not even be an issue but at a church when the pastor preaches I can see it being a problem. So I sent the amp off to a local tech who proceeded to bias the amp for me as I asked him to (unrelate work that I wanted done) and then tried to fix this hum. In the process he replaced some capacitors which he said we bad and says the amp is quieter now than when he got it. The problem is the amp is still humming which was the only noise I noticed when I sent it in. I called him back after discovering this and he was like "yeah that's a common thing with Fender amps...there is a mod you can do (something to do with mixing back in some DC current...I'm not technical enough to relate the mod to you all) that will fix this problem. So here I am now trying to figure out if I should send the amp back to this guy or is he just trying to get more money out of me? So my questions are...has anyone ever encountered this issue with their Fender amp? Second, has anyone heard of this mod or anything like it? Just to answer the question I know will come up...yes I play single coils and no this has nothing to do with the pickups. This happens when the amp is fully on with nothing plugged into it.