55 year old Fender Vibrolux Reverb amp............almost could pass for new......the dude I bought it from literally stored it in his closet at home and I believe him. I'm sure it's the original tubes etc and definitely the original two pronged electrical cord. So the issue may be grounding but I would love to retain all the original tubes and speakers etc and the original cord since these things have increased considerably in value since I purchased it a few years back (I was the 2nd or 3rd owner) and not have to haul it into downtown Dallas and trust someone to go over it.......but it has that typical constant humming and slight spitting. It does not go up in volume when I crank it so around "4" or "5" it's barely noticable but still naturally I'd love a sweet vintage quiet classic Fender amp...........any suggestions for a relative layman on electronics wiz to troubleshoot typical items that could correct this problem?? Thanks!! Jim