[mikethedruid]

Yes, Jake, and it is basically just a continuously variable version of how the original Philco tone control worked. I got the circuit from Everybody's Radio Manual, a Popular Science publication from 1934, page 114. It has the advantage of small size, simplicity, and is a circuit that was used in many radios of the period, including the little no-name set I am currently working on. It is really very similar to the circuit Philco used, just using a potentiometer and one condenser, instead of a resistor, switch, and more than one condenser. It also has the advantage of being easy to wire right into the original circuitry.