All demos are played directly into my sound card (LINE6 UX-1 USB interface) with some reverb only.

My final "live" solution is to use a stereo jack instead of a toggle switch, which I connect directly to a modified ARTEC-EQ. With my EQ I can compensate the sound difference between piezo and magnetic. This is the best solution for me, but you can also use a Y-cable and an A-B-box to sepeate the signals.

I made a discription of my EQ modification here.