YBA-1 Tone Stack Question

[GussyLoveridge]

If a potentiometer works on the premiss of variable resistance then how come in the schematic for my YBA-1 and in the actual build itself on the pin for the wiper on the bass pot is not actually attached to the circuit? I don't understand how it would effect the bass (or anything else for that matter) if that pin is not attached maybe I'm missing something altogether?

Looks like only 2 pins of the high range expander are connected as well.

What gives?

 

[PRR]

> the pin for the wiper on the bass pot is not actually attached to the circuit?

It is.

The symbol is shorthand. The circuit is adopted directly from Black/Silverface Fenders. Look at schematics with wiring diagrams. Usually the wiper is strapped to an end-lug, and just two wires come off the pot. This is a Variable Resistor. (Not a theoretical Potentiometer, though we do call the 3-lug part a "pot" even when we wire it 2-leg.)

The high-range the same, except it appears the far-end lug is not strapped to the wiper. In a 2-leg variable resistor, we don't care until the pot-wiper gets dirt and loses contact. When wiper breaks, does the circuit go LOUD, mute, or what? The bass resistor, when wiper breaks, will throw bass to 13. This may be annoying. With wiper-end strap, a broke wiper just goes to 10, which may still be unexpected, but not a poop-your-pants surprise.