Mixing piezo with a line level input?

[Jack.Straw]

Hello. I'm building a fun little travel guitar with a built-in amplifier:




(more images available at www.jugtones.com)

The internal amp is The Ruby schematic and drives a 8ohm 5.5" full-range speaker. There is a 1/8" input jack so that the guitar can double as an amp for your media player. The piezo bridge is switched so that the guitar can be turned on or off independently of the power switch. The idea here was to be able to switch on the guitar and jam along with music or pre-recorded accompaniment coming in from the media player. However, the signals don't mix when i simply wire the leads together. So, at the moment it works fine as a guitar, and fine as a media player, but i can't do both at the same time.

I've built a little piezo buffer that i'm going to put between the piezo and the little ruby amp, but i don't think that's going to be enough to make this work as intended. Is there something i can do to bring the piezo signal up to "line level" so that i can try one of the line level mixing circuits i've seen online?

Thanks for your time,
-Scott

[oc disorder]

Why not try something simple like this ?
You may need mixing resistors between the pots and pin 2. and
increasing the value of the 3k9.

[Jack.Straw]

Why not try something simple like this ?
You may need mixing resistors between the pots and pin 2. and
increasing the value of the 3k9.

Awesome, thanks!! Where did you find that?? Would you be able to recommend resistor values?