I found a diagram a while back detailing how one could wire a tone knob with two capacitors using an SPDT switch. This really appeals to me because I love versatility and what-not, but there was one thing I was curious about. . .

A capacitor will always affect the tone of the guitar whether the tone knob is all the way up or not. . . But what of two capacitors - one of which will be out of the circuit all-together (save the ground on the tone knob)?

Will they both always affect the tone, or only the one that is selected?

Reason I ask is because I have a NOS Soviet PIO cap and a NOS Mallory polyester cap - both of which should be very good, and both of which should also have diametrically opposite qualities - and I'd love to switch between them, but if they both are constantly affecting the tone, whether 'switched on' or not, it seems like it would be kind of counter-productive, no? Thoughts, anyone?

Cheers

Joe