EdBass's advice is spot on. With today's wall voltages, the original can cap is over voltage and should be replaced with higher voltage caps. Can caps are expensive and only come in limited values these days. The one available for the Sunn applications doesn't have a high enough voltage rating for today's voltages, plus it is cheaper to use the alternatives mentioned by Ed and myself. You can use discrete caps inside the chassis connected to terminal strips, and preferably connected in series to get a high enough voltage rating, but you can also just use the board he linked from Triode Electronics. They already have the series connected caps on it and have good quality caps on the board....its pretty much a plug and play. You just leave the can cap in place for cosmetic reasons, but disconnect it electrically. All the other electrolytic caps in the amp should be replaced too.
You would also want to verify the plate and screen grid resistors on the power tubes and preamp tubes are within spec. Those often drift out of spec and/or get noisy. Some of the coupling caps may have developed DC leakage over the years, and you can check these one at a time for leakage if you want to. The Black Cat caps tend to leak DC after this much time since new. The brown blob caps tend to work fine after all these years but they aren't very good quality and some modern replacements will likely sound better. Orange Drop polyester 6PS series come to mind, as do Mallory 150M caps. The power supply dropping resistors can also be checked for drifted values and replaced if necessary. Replacing these with metal oxide resistors would be a good choice as they won't drift value and they are non-flammable unlike the current ones in there. The "death" cap in the power supply should be disconnected and the power supply rewired correctly. The "death" cap in your pictures is the one that is connected to the ground switch. It looks like someone installed an IEC plug with a 3 wire ground, so just make sure it is wired correctly. You might also consider replacing the power tube sockets if they are badly cracked or look like they have arced. New replacements aren't very expensive. I like Belton sockets myself, although modern ceramic replacements are cheap cost-wise too. The main thing with those aside from quality would be to find new sockets that have the same hole size. In your pictures the sockets don't look that bad, but perhaps they just need to be cleaned with DeOxit.
It looks like quite a few parts burned or smoked near the power tubes and got that area of the chassis black. There are also some non-stock wiring and parts around those sockets too. Later when I get home I can see if I can post a picture of a stock 2000S for you. Since that amp doesn't have the sockets for the tube rectifiers and was solid state rectified from the beginning, then I would say it is likely from perhaps 1970-1971. What do you think about a date Ed and Loudthud?
Greg
