Cathode / Fixed Bias switch confusion

[WRC34]

Thx guys!

Colossal - the 6SL7s are old, one is likely 70s-80s production Sylvania w/red-orange lettering and flashing at the top. That’s the super microphonic one. The other is probably from the 50s-60s, it’s RCA I think, and shorter w/Raytheon logo and flashing around almost the entire envelope. I have lots of SL7s kicking around, almost all are old production.

Cathode bypass cap on output tubes is 1000uf 100V. Nice & hefty to keep those palm muted riffs semi-tight!

[Colossal]

Thx guys!

Colossal - the 6SL7s are old, one is likely 70s-80s production Sylvania w/red-orange lettering and flashing at the top. That’s the super microphonic one. The other is probably from the 50s-60s, it’s RCA I think, and shorter w/Raytheon logo and flashing around almost the entire envelope. I have lots of SL7s kicking around, almost all are old production.

Cathode bypass cap on output tubes is 1000uf 100V. Nice & hefty to keep those palm muted riffs semi-tight!

Thanks for the details. It sounds good! The Gold is a nice match with the amp.

[craftyjam]

eg

I know this is an old thread, but this schematic is confusing me, why is there a node that is on the center of the pot but not the center lug which is clearly connected to the 15k resistor? Are they both supposed to be connected to the center lug? Am I just over thinking this?

[xtian]

Because, maybe, the pot in this schematic is like the funky four-tap ones in old Fenders?

[craftyjam]

Because, maybe, the pot in this schematic is like the funky four-tap ones in old Fenders?

Ah I've never seen one of those before.

Is the 4th lug on these pots just a chassis ground connection, or is it an actual portion of the resistance track?

[sluckey]

Is the 4th lug on these pots just a chassis ground connection, or is it an actual portion of the resistance track?

It's a fixed tap on the resistance track. In this case, it's tapped to the center of the track and would measure exactly 5KΩ to each outer lug.