Linking circuits together. How do you do it?

[phantompowers]

I thought it would be really cool if I modified a bent keyboard by adding an optical theramin sort of thing to it. They both run on 6 volts so I thought I could run both circuits off the same battery supply, then link the speaker cables to the same jack socket. It didn't quite work as expected. The keyboard worked and sounded fine but the theramingy sounded really wrong and the LDR didn't work. I am quite new to this game and have a lot to learn so any information would be a great help.

[LoFi-Ninja]

What I get from your post is that you basicly just want to use the keyboard as a housing for the "theremin"

Try putting a passive mixer on the outputs and then to the jack.
Here's a really easy one. You may need to change component values if the volume is too low.


Anyways I thought this thread was about injecting signals into different points of different items.. Here's a recent experiment I had. Have a look at my video here.. At 1:45 I have a drum machines output tied to my finger and then playing the body touch points..

http://www.youtube.com/watch?v=2LNRnB1htLA

[phantompowers]

Cheers for the reply. I'll try that.
Nice headache inducer by the way!