Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: plumcrazyfx on July 08, 2018, 08:52:59 am
-
I'm running out of space in my build. I'd like to free up some space using a cap can. Problem is I think I need to series them like in big Fenders with the 220k balancing resistors. Problem is they all have a shared ground for the 2 caps. Could I use 2 47uf cans- tie each of the two sides together in parallel and series the two pairs to get higher voltage rating? This would end up with 47uf 900v right?
-
Yup, maybe, is the "can" part the same as ground, if so the "top" can will have to be completely isolated so it don't touch ground. It will be like having a giant lead - live @ big volts
-
The ground lug isn't connected to the outer shell on JJ or F&T as far as I can tell. I know they are on some CE Mallory types.
-
Lots of folks have done that, including Marshall.
-
I've done that with some older LCR can caps. Just because it has a negative lug/terminal doesn't mean the outer shell isn't also connected, so you should check continuity if there are any exposed metal parts. In my case this was a problem with one because the top cap was metal and "grounded" (negative) even though the rest of the "can" was plastic + shrinkwrap. With the others, the top was plastic too and there was nothing to worry about.
-
I will check it out. I'll be using JJS in one build and F&Ts in the other.