It's a teriffic preamp that has worked on every other piezo pickup I have tried on it. It couldn't provide enough gain though for the Dynafield. Didn't do the job. Results with Dynatech poor. This did a decent job.
Second problem is with design.
The pickup works by sensing the movements of the top. During installation, one superglues what looks like a concave metal button to the bridgeplate. I am going into this detail because I think this sytem has such great tone that its worth redesigning it. I don't know how you do this, but I would try. Hope this helps.