Re: Resonator pickup?
I have a Republic Mandolian I electrified:
I have 2 pickup systems installed. The Lace Sensor resonator pickup in the cover-plate is the obvious one. It is a super-thin humbucker Lace developed in collaboration with National. It requires a non-reversible mod to the cover-plate, but it actually works well.
The other pickup is a piezo like this:
My local electronics store sells them in packs of 10 for $5. I drilled a hole in the center then placed it between the screw and the cone, underneath the bridge - goes something like this:
Each pickup has it's own volume control and output is via the 3-way selector switch. I used a TRS [stereo] output jack and run the piezo to the Ring when the 3-way is set to the Lace. That way I can split the signal with a stereo cable and run each to their own amp/whatever.
The piezo provides the best acoustic tone but is prone to feedback at gigging volumes. The Lace is darker and more "electric guitar" sounding, but works in a pinch when needed. I find a blend of the two gives some pretty pleasing tones.
Purists will scorn my mixing of pickup types like this, but in applications where installing on-board electronics is problematic, I default to what works best for the least.