GraphTech Ghost Peizo with Hipshot Bridge (4 str.): Mechanic's Special, $230.
Here's the story: I had this installed in my bass for three years and it worked fine. It is a very interesting addendum to an electric bass. Then one night it failed, in this manner: I lost all mids and highs, as well as significant volume. A few tweaks at the amp and we completed the evening and no one knew but us. I had tried a new battery with no change.
Naturally I was a little spooked by the experience. I moved up plans to make some other changes in the bass and removed the Ghost system very carefully.
The price here is the cost of the Hipshot bridge alone because the Ghost system is a big question mark. My hope is that you're interested enough in working through the unit and getting it going. If that should not pan out, you'd still have the bridge, which can be used normally. Does that sound fair enough?
The GraphTech site has some thorough troubleshooting steps. Because the system is modular with plugged-in sections, it is easy to eliminate a single segment and get a diagnosis that way. I just don't have the time for that right now.
The control layout: Master Vol, Pickup Blend, Tone, Peizo Vol (push-pull mid-dark type).
I clipped the leads from the jazz pickups (black/grey and white) and the battery leads are also clipped, red and black. (I used an on board double battery box.) I will include the unused battery snap-top with leads and the single battery clip.
The pot for the piezos is the push-pull mid-dark type.
$230 shipped (USPS Priority) conus, PayPal.