What sonic benefits will I realize from a cap job (will it reduce hum and noise)?
Allow me to answer your question by offering what a friend of this site had to say on the topic. The first thing I do when I buy a vintage amp is is give it a cap job, and replace every resistor in the power tube sockets (if they are at least 10% out of spec). Whe n I got my Sound City amp it sounded terrible; it was noisy and weak for a 50-watt head, and it hummed really bad. One of the problems was a bad capacitor on the ground selector (the .047uf X 600V cap). Usually when I get an amp, it has been sitting around 10 years or more (at least the last three I bought hadn’t been turned on for 10 years from what the former owners told me; this one had been sitting for over 20 years!), so the caps are all dried up and useless. To reduce hum, I cut out the old AC cord and install a new 3-prong modern AC cord and grounded the third prong to the chassis. That usually helps out a lot. New filter caps will greatly reduce hum but will not get rid of it 100%. Next to your tubes, the caps are the
