Bill Moore wrote:BTF, did you voice more than one channel to the bassman circuit? I too have a DR AB763 project, but want to voice one stock, and the other to the bassman circuit. Did you lower the voltage to the bassman channel tubes, or leave it at AB763 levels? I'm thinking I need to add 1 more cap, and resistor in the rectifier circuit to power the 59 bassman channel tubes. I appreciate any ideas.
hired hand, that is really a nice project! Did you decide to stay AB763 on both channels?
I built a Twin clone and used the OT from a 94 Twin. 4.8.and 16ohm outputs, and a winding for a line out,(XLR). leaves lots of possibilities open.
A good question I suppose. There is all kinds of discussion regarding mods to the first channel of a Bassman head, but I never read/hear much about changing the first channel of a Twin. I would be curious to hear what some of you guys have done with the non-reverb half of a Twin.
My amp is going up for sale when I am finished, so I have a feeling it will be an easier sale for me if the amp is kept stock.....
Bill (my name as well, by all means please call me Bill!):
This thread has gotten a bit crossed, but I can offer my experiences with both amps. We first began the post with Twins. A few years ago I was working for a Fender service center (among other brands) when out of the blue a couple gave me a Fender PA100 head (nothing more than a Twin Reverb Fender had modified by adding 4 mic channels with volume, bass, treble and master reverb). I don't need tremolo as I have a rack unit for that, and tremolo is a bit of a tone sink in the 763. So I built a single channel Twin head using the 763 circuit, reverb and installed a new faceplate. However, instead of the 763 tone stack, I had some vintage .02uF caps, so I installed a plate-driven '59 Bassman tone stack. I absolutely love the tone. Like I said, warm and jazzy or thick and twangy. To be honest, I've never cut it above 4, so I can't say what its overdrive sounds like.
I also have an 864 Bassman whose Bass channel I found wretched and also installed a plate-driven '59 Bassman tone stack. I previously had a Ken Fischer-suggested preamp design in there which also sounded stellar, but brighter and tighter than the Bassman. The '59 Bassman tone stack doesn't have as much mid-cut and a tighter bass which works better for me when I'm using my rack. When used with just the guitar, I like its warmth. Kind of early Johnny Cash meets Clarence White and Bob Bain for a jazzed-out twang fest...
