main filter caps wiring

[Doc Stitches]

I need a schematic or a photo for complete wiring of main filter caps for 68 Bassman

I can't find the one I had and the Fender layout and schematic are no help.

This amp was a basket case/partial mod with many missing parts and wiring issues.



Thanks
Doc

[mozz]

Working on the same thing right now, 68-69. I went to google images for help. there are a few different ones depending on the circuit, aa165, ab165, aa864.

[Justin Thomas]

Doc, that looks to be an AB165, or someone was trying to make it one. Honestly, everyone but me seems to hate that circuit... the 220k resistors from power tube plates to grids are a giveaway. Not sure if you've been looking at an AC568, but I bet an AB165 will make more sense for you... I can't post one from my tablet, but the schem and layout are out there.

HTH,

Justin

Mozz: possibities are AB864, AA165, AB165, AC568, AA270 I think, A??71, then you hit Bassman 50 w. & w/o. MV.
The AB165 & AC568 both have very strange features that ID them right away. Power supplies have always have been "fluid."

[Doc Stitches]

AB 165 ... I just can't find how to hook up the main filters in the dog house.

[Doc Stitches]

Sorry, Justin .... it is an AB 165.

I just can't figure out where the schematic or layout shows me the wiring for the main filters in the dog house.

Jim

[Justin Thomas]

The layouts never showed that... you'd have to figure it out from the schematic. One thing I don't do if I get a basketcase like that is to not use the jumper wires under the board like Fender did. But the two big caps should be wired in series, each with a 220K resistor across it. Then the ground of that "assembly" gets connected with the grounds of the other 4 caps, though there may be a separate wire for the big ones.

The four small caps have their negative ends joined with solid wire between the eyelets.

Don't worry about if it looks right, as long as it works. If anyone has a Bassman head with 6 caps, it'll work. They're all the same.

Justin

Edit: it's a long shot, but after Christmas, I may be able to get a friend to dismantle my amp over the phone & send me some pics...

[KilgoreTrout]

Google says this:

Paul P's Amps: AB165 Bassman Refurbishment & Modification

I hope it helps.

- Kilgore

[Justin Thomas]

Wow, very helpful pics but he really hates that circuit! I'll bookmarks it for reference, cuz you don't see many of these in BF.
As far as the "high-sucking" caps, well, it <IS> a BASSMAN! Anyway, mine still has them and is not lacking in sparkle. Of course, mine also has a Twin Reverb OT, so...
It's fat. I don't mess with it. As far as the soldering, they flipped the boards over and soldered from the bottom. Hence the blobs on top when mounted. (Thanks to Tom Phillips for that nugget.)
What the heck is a "Virtual Earth Mixing Stage?" I just go with Andy Ruhl and call it a "compressor."

Justin

[Doc Stitches]

Google says this:

Paul P's Amps: AB165 Bassman Refurbishment & Modification

I hope it helps.

- Kilgore

Thanks Kilgore. With everyone's help, I should have this amp finished next week when the main filters arrive.

[mozz]

http://www.mojotone.com/Amp%20Kit%20...s.pdf?gc=clear

[Doc Stitches]

http://www.mojotone.com/Amp%20Kit%20...s.pdf?gc=clear

Hey Mozz

Great photo ... absolutely no excuses now .... I actually looked on Mojotone and missed it......duh

Thanks to everyone
Doc

[mozz]

That doesn't showup on their website too easy, found it through google.

[mozz]

One more thing i just noticed while wiring this up, it appears the board with 6 caps, they have the 1K and 4.7K resistors mismarked.

[Doc Stitches]

One more thing i just noticed while wiring this up, it appears the board with 6 caps, they have the 1K and 4.7K resistors mismarked.

Hey Mozz ... good on you for catching that mismark ... I wonder how much that would change things ?

I'll bet many have made that same mistake.

Doc