'68 Bassman amp volume

[Justin Thomas]

My only experience with a BF head (not sure of the circuit, cuz my AB165 IS a BF...) was thin, weak, and anemic. So I'm sure it needed "help," so I'm not going to bash anything I haven't played... The sad part is, I like them stock, and so many have been "modified" because Bassmans are just seen as hack fodder... That poor Bassman 50 I bought comes to mind... Poor little fella, if someone thought that was a successful "Marshallization," they've never played a real Marshall, either. Besides - why trash a Fender? Just get a Sovtek and don't do anything to it - Best. Marshall. Ever. Never played a blonde Bassman, either. But might build one sometime.

I could see cutting some of the bass out of one of the channels, but that's just a Fender problem in general...

Justin

[Doc Stitches]

Can someone say "Rock n Roll ? Thanks to everyone here at the forum, it's that time here in Santa Cruz Ca. This Bassman is alive and screaming ....

Very quiet with no hum. Volume on 1/2 is good and on 3 the windows start to bulge. The Bass channel is good but the Normal channel is way over the top !

Of all the BF and Sf amps I have worked on this puppy takes the cake. So here is what I did today :

Rewired heaters on V2, v3, v4, v5, and v6 ( not matching pins )

Bypassed ground switch

Wired 100 ohm resistor from each filament to ground

Checked and cleaned up some more solder joints ... mostly bias circuit and near PT

Hey Chuck ... I am going to look into the AA864 conversion/comparison. Maybe this Bassman will get another " facelift" ?

I just really hate to walk away from this sound. Is there a lot to change from AB165 to AA864 ?

Again THANKS to everyone

[Chuck H]

No!!!! Don't change it!

Once you're there you need to stop. That amp is great they way it is (so I'm told ). I can also speculate that the head I heard was an exceptional sounding one. Like Justin said, there are others of the same model that can sound anemic. My mission at my bench, whether it's one of my designs or someone else's amp, is to maximize THAT amp. Never to make it into some other amp. Well, unless that would maximize it I suppose. But my point is, just because you like cherries you don't chop down a good apple tree to put a cherry tree of unknown quality in it's place. You take care of your apple tree.

Besides, the transformers will be different. The voltages will be different. You almost certainly won't be using the same speakers I heard that amp through, etc., etc. All this can change the nuances that make the difference between just good and WOW. I got WOW. You might not. Doesn't seem worth it.

I think the circuits are pretty similar anyhow.

Glad it worked out.

[Justin Thomas]

Doc,

No!!!! Don't change it!

Once you're there you need to stop. That amp is great they way it is (so I'm told ). My mission at my bench, whether it's one of my designs or someone else's amp, is to maximize THAT amp. Never to make it into some other amp. Well, unless that would maximize it I suppose. You take care of your apple tree...

I think the circuits are pretty similar anyhow.

YES! Please leave it alone! Look, there are some VERY tiny things you can do to try, but seriously - part of that "conversion" is to alter the third stage. THAT is the main difference, and I think is the magic that makes the AB165 and all others that follow so special. The other difference is the local negative feedback on the 6L6s. Mine had those removed when I bought it, that was it. As you said - Rock&Roll! People get on here all the time, "my Bassman is distorting on 4... Fenders should be clean til 10... Is this normal?" In the case of these bad boys, yes, completely normal. These ain't toys, and they're just a kickass rock amp. Dang, if I had the money... If you want to change it, well, can I have it? Plus - they are an awesome bass amp, too. <IF> you have a proper speaker. That means old-style and efficient.

I even chopped a tube socket in my Bassman 100, so I could add that 4th preamp tube... Now I have a 100W AB165, basically. You have an awesome amp. Tweak it, but take a lot of pictures to return it back to the way it was if you do. If anything, fine-tune the bass rolloff using caps in the tone stack, to avoid as much fart at the volume you play at as possible. But other than that... Wow, I played lap steel through mine with a Seth Lover in the bridge, holy cow, auto-sustain, and that kind of 'perfect octave' feedback. My only regret is that Svet 6L6GCs aren't available anymore...

Justin

[Doc Stitches]

OK ... Chuck and Justin ... You made me see the Light. Bassman it was and Bassman it stays.