tweed bassman build

[Firestorm]

Beautiful build!

I'm with Firestorm, do try flipping the phase to try it out. When I first heard of this I didn't believe it, but I tried it in a small combo and it was noticeable.

I actually measured this in a very unscientific way: the fixed field behind an alnico extends straight back and can deflect a compass needle 17 inches away. That field is modulated by the signal, so you gotta believe a tube sitting in that field is affected somehow. Probably not the electrons travelling to the plate 'cause they get up to about 70km/sec. by the time they hit the plate, but the electrostatic fields in the tube have to be affected: notably the virtual cathode, which we were on the verge of understanding when all the smart guys transitioned to solid-state. Just a recurring interest of mine, arcane though it may be.

The magnetic field behind a speaker is fixed because it's a permanent magnet. The field coil gets the AC signal from your output tube. Changing the speaker polarity does not change the strength or orienttion of the field from the permanent magnet. I doubt a tube is influenced from the magnetic field from the speaker. Stick a strong neodymium magnet up close to one of your output tubes and see if you can hear a difference while playing.

Actually, that fixed field is seriously modulated by the signal (otherwise the speaker wouldn't work). A neodymium magnet is 0Hz. We're exploring the impact of a changing field.

[LeftyStrat]

There's also the issue of mechanical vibration. Also phase of the speaker wrt the AC input (which some have claimed makes a difference).

I don't really have any knowledge in this area, but what kind of fields are produced by the output transformer? Could these have a phase such that swapping the primaries might have an effect on the circuit?

[cbass]

There's also the issue of mechanical vibration. Also phase of the speaker wrt the AC input (which some have claimed makes a difference).

I don't really have any knowledge in this area, but what kind of fields are produced by the output transformer? Could these have a phase such that swapping the primaries might have an effect on the circuit?

Umm I'm not even smart enough to grasp whats being said but if you swap primaries on an amp with NFB it will squeal and howl.but you knew that

[LeftyStrat]

There's also the issue of mechanical vibration. Also phase of the speaker wrt the AC input (which some have claimed makes a difference).

I don't really have any knowledge in this area, but what kind of fields are produced by the output transformer? Could these have a phase such that swapping the primaries might have an effect on the circuit?

Umm I'm not even smart enough to grasp whats being said but if you swap primaries on an amp with NFB it will squeal and howl.but you knew that

Yeah. I'd probably do the experiment with an amp that had no negative feedback.