My 1991 Fender Bassman Reissue amp is a beast. It is the loudest Bassman I have ever heard, and several other blues players have told me the same thing. The tone is deep and massive, never muffled. It is a wonderful large harp amp.
I bought it for a single purpose: I was playing with a very loud (and very good) blues band and I was having trouble being heard and hearing myself. All the mods I did to the amp were done with the idea of making the amp much louder and giving it a deep crunchy tone that I like so much in harp amps.
There was a lot of trial and error at first, but over several months I got it perfect. It is muscular and punchy, but still responds well to pressure I put on the microphone. There is a bit of tearing on the edge of the notes (if I want it) and some warm crunch when I want that. It is versatile and powerful, and it gets immediate attention when I lean into it and dig in. Standing in front of it I can feel the sound pressure level as I play. And it never feeds back until I get to stupid levels.
Well, here’s the problem: I’ve changed bands, and the new band does not play nearly as loud. At a gig last weekend I kept turning down so I wouldn’t overwhelm the band. I had to get the level on the Bassman down to 2 1/2 and the mic turned down halfway and I was playing softly. At that point I blended with the band but I missed the raunch and power. The Sturm und Drang.
So, I can try using a different combination of preamp tubes, but that will soften the bite of the amp. The preamp tube lineup right now is 5751, 5814a, and 5751. The 5814a is a military 12AU7 tube. I’ve tried nearly every combination of tubes possible in this amp and this setup produced the tone I was chasing, so I am reluctant to change it. The circuit mods to the amp are no secret: They are the changes you would expect a good tech to make to this amp, including a bias trim pot for the power tubes which are biased rather cold. The power tubes are 6L6 and the rectifier is 5R4.
A big part of the character of the amp is the two Eminence Lil’ Buddy speakers installed in the bottom of the cab. These speakers are very efficient and have a deep and colorful tone. The other two speakers are original Fender Blue Alnico.
I use a Kinder AFB+ pedal to help control feedback and an MXR Carbon Copy delay pedal to fatten up the sound.
I plan to tinker with the settings (not the tubes or circuit) to see if I can get some of that monstrous character at lower volumes. The amp is right and I really don’t want to tinker with the internals any more. Of course, it makes sense to leave it at home for most gigs and take a smaller amp, but I am kind of hooked on that big tone, and it is cool knowing I can muscle aside all but the loudest bands.