Output Transformer for a Bassman

[MysteryFever]

Well, I replaced the blocking caps (which were of the .047 value) with .022's and I'm thrilled with the change in bass response. There's still plenty of bass, but it sounds tight, smooth and much more usable. Thanks all for your replies!

[billyz]

I just got another ab165 in yesterday. Some one had tried unsuccessfully, IMO, to Blackface it. After the basic overhaul, I will be "Wrecking" the bass channel, with a few twist I call the "Longhorn Mod".

[MysteryFever]

Oh do tell! What's the Longhorn mod all about? It doesn't have anything to do with a cathode-following tone stack does it? I've tried twice to throw one of those in this amp and I always end up with oscillation past a certain volume. I think what I'm doing wrong is that I never paid attention to which B+ leads were powering which plates and you need to isolate the one on the stage preceding the tone stack right?

[billyz]

Oh do tell! What's the Longhorn mod all about? It doesn't have anything to do with a cathode-following tone stack does it? I've tried twice to throw one of those in this amp and I always end up with oscillation past a certain volume. I think what I'm doing wrong is that I never paid attention to which B+ leads were powering which plates and you need to isolate the one on the stage preceding the tone stack right?

No Cathode followers, I don't find them very useful. Maybe for a preamp that is located a long distance from the power amp. This one was a bear due to the previously poorly done blackface job and the nature of the ab165 amps ( the worst circuit IMO). It is a pretty involved reworking of the bass channel mostly. I am going to write whole process up with schematics, but the work varies some from Bassman head to bassman head due to the different circuits you find. Let's just say the wreck people would recognize some of it.