My Traynor YBA-4 has always had a bit of a hum to it, that starts as soon as I power it up, it also seems to be slowly getting worse. I'm guessing its time for some new filter caps (has originals), but just wanted to get some verification before I tear into it. The amp is sitting right next to a SUNN300T and a Blues Jr. and both those are nearly silent when I power them up, so I don't think it's anything from the power or room. I also just bought an old Kay transistor amp that has a very similar hum, but even louder which is what got me thinking about this. So I'd say I'm 86.7% sure I need to recap, but I wanted to let those with a bit more wisdom on the subject verify it for me. Thanks.