Two Volume Pots

[Jack.Straw]

Hi guys. I'm trying to mix a piezo signal with a line level signal inside of a little practice "ruby" amp. This is the schematic i'm working from:


This is how i have the volume pots wired:


That isn't working... the volume pots both control both signals. Can someone help me with my logic error?

Thanks!!
-Scott

[black_labb]

when one of the signals are at 0 there is a short of the hot to ground. essentially it works as long as you dont have one of them too close to 0. you could either put a resistor between the wipers on each pot and pin 2 (not sure on the value, you want it to stop the interaction but not cause too much impedance change, maybe 5k?).

otherwise you could swap the hot end of the pots and the wiper. this is how it is done on a jazz bass where you blend the 2 pickups.

[Jack.Straw]

otherwise you could swap the hot end of the pots and the wiper. this is how it is done on a jazz bass where you blend the 2 pickups.

BL... thanks!!! So it would look like this?

[Albert Kreuzer]

Yes, except that I would add a small resistor (1k...10k) in series with the media player output. Some players do not like shorted outputs.

Cheers,
Albert

[Jack.Straw]

Thanks Albert!

[Jack.Straw]

Albert, when you say media player output, do you mean between pin 2 and the media player, or between pin 3 and the amp?

Yes, except that I would add a small resistor (1k...10k) in series with the media player output. Some players do not like shorted outputs.

Cheers,
Albert

[Albert Kreuzer]

Between the media player and pin 2.
So when you turn the pot to zero, the media player will still "see" the resistor between output and ground.

Cheers,
Albert