Re-Caps for my 1963 Brownface Bassman

[Johnny1958]

some saping copper brade, small soldering wire... and

2x (just in case) 220k 2W metal film resistor to bleed caps (paralel shorting)

Metal box cover:
5x Sprague Atom 20uf 500vdc

Board:
4x 25uf 25vdc
2x 25uf 400vdc
1x .047uf 400vdc (smaller body)
4x .1uf 400vdc
1x .1uf 200vdc (also smaller body)

Off board:
1x 100uf 100v (bias)
1x .047uf 600vdc (ground)
.......................................................
ok thks, i knew the uf & mfd= same / just the value on the caps looked like .Lmfd, was wondering if it was a .L or a .1 / i know .L makes no sense, but just so i'd be sure it was a .1uf

So i'm off to the cyberstore, i hope i can find all in one place

[BiBi]

I think you need to look over the thread again before you order. 500V is not enough voltage for the first cap "under the metal hood". Your transformer is putting out more than that which means you will smoke your new caps and perhaps your power transformer. You need to put two high uF caps in series to get a higher voltage rating just like MWJB said:
"Easy option - replace the caps in the pan with F&T 20uf 550v caps from TAD, these will handle the voltages in your amp and be the simplest replacement. For best tone however, I'd rewire the main filter caps (the 2 in parallel, nearest the power tubes) with 2x100uf 350v Sprague, or 2x220uf 350v F&T caps in series, each cap bypassed with a 220K 2W resistor. You will need to remove a jumper under the cap board at the positive ends of the main caps, so that the new caps can go in series (not parallel like the old ones - see how the Super Reverb caps are wired), you will have to move the ground (black) wire that connects to these caps to the "-" terminal of the 2nd series cap.

20uf 500v/550v volt will be fine for other positions in the cap pan. "

Avoid this at your own risk!!

[Johnny1958]

Oops! true thks, I'll need 5x F&T 20uf 550vdc for the pan!

I found some F&T 25/25uf 25vdc with a double + end. you figure that would be a good replacement instead of doubeling two single caps ?

I'm starting to feel like an idiot real fast!

[BiBi]

Oh we're all idiots sometimes. Anyways like they say an intelligent person realizes how much more there is to learn!

Now, I still think that MWJB had it right on that first cap. Putting two in series is a good protection and maybe it sounds better. Plus two 350V caps are usually cheaper than a single 550V one. Again it's your choice, but since your power transformer is putting out over 500V after rectification (have you measured this by the way?) a 550V cap is borderline-- even the originals were 600V.
As to the two cap in one, I don't think it matters that much. It might be just more of a pain to get it in there than separate caps.
Make things easy on yourself at the beginning. The problem I always have as well is thinking about it all too much. Replacing caps is a simple solution. You want to get a high voltage and temperature rating to make sure your caps and your amp run well. Amount of capacitance is a matter of debate and taste but at least sticking with the original values won't hurt.

[Johnny1958]

Thks for your kindness lol

Well, i did not check the voltage thus far, i havn't done much anything until i get the replacement.
This is still pretty new to me.. I did not know the original capacitance of these "under cover" wink :P caps were of 600 vdc, i thought there were 500vdc!!! I'm trying to replace everything to original value and in the same setup as possible. i'm kind of an high audio purist without elctc's high knowledge!
but if you bare with me a bit, i'm sure i can get it done nice.

Many Thanks