A while back I was in my F2-B preamp to fix what ended up being a broken solder joint on one of the power supply filter caps. I really wanted to replace them altogether at that time, but the only high voltage electrolytics that I could find from my usual component vendors would have cost upwards of 80 bucks for the set(!).
Forward to just recently, and this thing's started humming something fierce. I figured these 30+ year old caps finally gave up the ghost, so I went looking again and found a place called Just Radios (http://www.justradios.com/ (http://www.justradios.com/)) who specialize in restoration parts for old tube radios. Found a set there for just over $13, and their turnaround on the order was really fast.
Well, that fixed the hum and the old preamp sounds mighty fine once again! Honestly I wasn't sure if/how these "cheapie" caps would compare to the rather expensive Cornell Dubilier replacements. If any of you amp gurus have opinions on that, you won't offend me- might be good to know for future reference.
Anyway, just thought I'd share that source in case it helps anyone else.
(http://i87.photobucket.com/albums/k125/0chromium0/forums/alembic/f2b/DSCF0045.jpg)
I know I'm really pushing my luck with those in my Hiwatt, dated '69
I have a (reasonable) UK source, but time has...
I just went wottheheck and had all of them replaced in my '67 blackface Bassman. Had a grounded AC cord installed at the same timeb
I've been in the habit of trying to plan ahead and replace the power supply caps whenever I have to crack something open for service. This is the only high voltage device I've worked on, though. Usually its old keys or effects, and their low voltage caps are easy to find at mouser, digikey, allied, etc...