Paraphrasing Scott, if you run two cabs of equal impedance in parallel, you want the amp set at half of that impedance. In your specific case, it sounds like you're using the 1960 cabs that have a stereo/mono switch, which allows you to access two sets of two speakers each at 8 ohms per set, or all ...

Even later Bandmasters have those "plugs" over two extra holes in the chassis. And yes, the one you're looking at here was modded for 4 6L6s. It also has a bigger output transformer than stock--presumably to handle the extra power. The AB763 circuit with 4 6L6s is for the Showman, which is...

It's hard to say why you hear the problem on the Twin and not the HR Deluxe--could be a few things that aren't necessarily flaws. My point about the Twin was that, unless you have the output of the pedal very high up, you're not going to make the twin clip the attack of the signal, especially after ...

I bought a fuzzbox in Vietnam last year which does actually look like a homemade explosive device: a plain, grey, folded metal box with three knobs, a flashing light that kicks in when you turn on one of the knobs, no text indicating anything, etc. I considered mailing it home with some other little...

Yea I can definitely get rid of most of it by turning the guitar down, and the gain on the pedal down as well, but then I feel like I'm compromising. I had the guitar setup when I first ran into this problem and had the guy set the pickups really low in the body, which also helped, but didn't solve...

The pickups on your SG are most likely considerably louder than the pickups on your Jazzmaster. This would account for the difference between the guitars in the same set-up. Try turning the volume down to maybe 8 on the SG, and see if the problem still happens. If it does, it probably means the the ...

I think Scott's on the right track. Did the lamp/light go off (on the amp--if you took out all the lights in the room, congratulations!)? This would indicate the fuse blowing. What you're describing sounds like an output tube dying; it will often take a screen resistor with it. If you're feeling adv...

thirded.

The treble control in the schematic looks like a regular pot, assuming this schematic accurately represents your amp. I'd check it (out of circuit) as Rodabod suggested, to see if that fourth point has any measurable resistance to the rest of the pot's lugs.

-Tom

A fourth lug probably means it's a tapped pot, which has the usual two legs and a wiper, plus a tap off the resistive strip at a set place. Your drawing looks consistent with this. One place I've seen them that comes to mind is in the tone circuits of some brown Fender amps from the early '60s. Oh, ...

There are three (documented) circuits for blackface Bassman heads: AA864, AA165, and AB165. These designations can be found on the tube chart inside the head cabinet, and (roughly) indicate the month and year of the design, eg: August '64, Janauary '65. To make things more confusing, the tube chart ...