y-switch question

["Michael Peters" <mp@mpeters.de>]

Title: y-switch question

non-loop related question:

I want to use either-or or both of two sound sources (guitar, and guitar controlled synth), so I plug them both into an y-switch feeding my amp.

That seems to work fine at first, I can switch between guitar and synth without problems, both are loud and clear, but when I set the switch to "both at once", the guitar is suddenly very low in volume while the keyboard is as loud as it was. Why is that? is there a remedy?

-Michael