champ tone lift

[clock10]

Hi, has anyone got a layout for the tone lift mod on a champ using a dpdt/250k pot in place of the treble pot.
Cheers

[Jazz P Bass]

I would replace the 250KA (log) bass pot with the same pot with a switch on the back of it.
At the switch, connect the 15K bass pot tail resistor on one terminal & ground on the other.

[clock10]

Thanks jazzbass for the reply. I read that lifting the earth on the bass pot would not take out the whole tone stack only the bass. Is that right?
Cheers

[Alex R]

No, it would change everything in the tone stack and remove most of its effects. Try it and see, it is easy to do. Lifting the 18K resistor from the bass pot, the one that goes to ground, gives you something very close to a tweed champ. The little bit of filtration left in the circuit by doing that doesn't amount to much at all, it is still there but it will pass most of the signal. The point of the tone stack is to dump various frequencies to ground, so when you lift that resistor most everything gets through. Someone will come and do the maths if you insist! (but it won't be me as I am too stoopid)

[clock10]

OK, great thanks, I'll try it.
Cheers