Suggestions for an AB165 Bassman

[crummycar]

This is a '70/'71 Bassman and i want to retro the circuit to be a better guiter amp. I am not looking for heavy drive, just a good clear tone. This is an as built drawing of what it is today. Thanks.

[Satamax]

This is a '70/'71 Bassman and i want to retro the circuit to be a better guiter amp. I am not looking for heavy drive, just a good clear tone. This is an as built drawing of what it is today. Thanks.

I should say i'm not too keen on trying to read the schemo, but i have to say a thing, if you don't mind modding, change the circuit to AA864, get the bass side to super reverb specs, , add a switchable tube recto, put a 10K pot in line with the 820Ω nfb resistor. A guy bought my old bassman moded like this, and he's a pro, he's been amazed ever since

[Amp Kat]

The first tube 12ax7 only uses 1/2 of that duo-triode so you can use it for more gain however I'm not sure it's going to give you the amount or sound you want.

[Regis]

I agree with Max, redo it resembling the AA864. I did that more or less to my silverface bassmans, they sound great. It probably has those turd brown caps in it, replace them with orange drops or mallorys, and replace the electrolytics. Rewire the bias to be adjustable fixed, I have .1 coupling caps there in the output section. I did the bass section in my BF bassman like a super reverb and it sounds good. Some guys do a Marshall or Tweed setup in the bass section.

Not sure about punching a hole for a tube rectifier, that's not reversable.

The 10k pot/820 nf thing is the Soul Control, right Max? A variation of that is the Resonance Control, I put that in my Bassman 100 and it give great range.

[crummycar]

Thanks

Thanks for the suggestions. I am not too concerned about making changes to this head. It doesn't have much "vintage" value. Sounds like the AA864 is the way to go. Can this amp simply have the circuit board replaced with an AA864 replica and re-wired to match the AA864 schematic?

[Satamax]

Some other fender mods

http://vintageamps.com/plexiboard/viewtopic.php?t=54111

[Regis]

Thanks for the suggestions. I am not too concerned about making changes to this head. It doesn't have much "vintage" value. Sounds like the AA864 is the way to go. Can this amp simply have the circuit board replaced with an AA864 replica and re-wired to match the AA864 schematic?

You can replace the board but unless it's damaged or otherwise messed up you can rewire the old board to AA864 specs. You should still do something different in the bass channel. Just get both layouts for the AB165 and AA864 and go to work.

[Matt T.]

FWIW, I did the following to my BF Bassman:
Changed the power section/OT/NFB to be like a regular BF amp.
Wired the Normal channel to be like the Normal channel on most BF Fenders.
Wired the Bass channel to be like a tweeked-for-guitar version of the 6G6B Bass channel. The 6G6B circuit uses all four remaining triodes. That tweeked 6G6B circuit is one of my favorites.

[crummycar]

Thanks

Thanks to everybody who responded. These sound like really good ideas. I'm too busy right now to get anything done with this amp, but I'll keep this feedback for when I do.