Caleb, forgive my lack of technical knowledge, but if a passive pickup can be soldered in, will using a regular mono guitar cable only pass the lyric's audio or would it only pass the additional pickup, or maybe no sound at all?
I ask because I'm considering a sort of a/b system in order to choose an already existing fishman transducer if for some reason the environment I'm playing in causes too much feedback or there's just too much ambience. Guitarists like options!
Using a mono cable will pass the Lyric signal only. Using a stereo Y cable would allow you to use either the Lyric channel or the Piezo channel with different channels or a stereo blending preamp.