Just got a used DRRI for a little over $600 on CL, with an extra speaker too (WGS ET65). Playing it, I notice the reverb is a bit weak and the tremolo ticks. For the reverb, I clean the RCA contacts, try another set of cables, change out some preamp tubes and try the tank in another amp (it works as expected there). I may get a reverb driver/transformer if I want to do surf. On to the tremolo - poke around with a wooden skewer and move the small gauge wires around from the board to the tube sockets and instant win, tick gone! Play it for a little bit and it sounded a little thin, thought it was because the chassis and the reverb tank were out and the back was off. I go back over to the amp and it starts humming and getting louder. Oh oh, switch the standby off and still humming loud and then shut it off. One of the 6v6s was really hot and it's a black glass GT tube, so I cant see if something went wrong with the tube itself. What are the chances a power tube goes at that moment? Every time I do something with an amp something goes to sh*t. I was going to get new tubes and put them in but I did a little reading about power tube failure and the hum which could be bias supply problem and grid resistors going bad. Where are they on this amp?