I got he SH5 for a 40 year old Guild D-25 I wanted to electrify for performances. I liked the idea or a mic/piezo blend. I installed it myself, which you can do if your handy. It involved drilling a 1/8 hole in the bridge and sanding down the saddle to accomodate the piezo. I swapped out the cable jack for a more standard barrel jack, which required soldering the wires. Glued the controller with epoxy. The mic was way too loud relative to the piezo but as a recall there was a screw to adjust the volume, as well as the slider to blend the two pickups. If you have the mic volume up it will feedback. But with just a little mic, it blends in with the piezo output to create a softer, pleasing sound.
