Nice catch—that explains the extra controls! That little toggle switch on the front panel activates or blends a hidden piezo acoustic pickup system built right into the saddles of the bridge.
Having both the magnetic pickups and a bridge piezo on a 90s Carvin is a premium, highly sought-after custom option. It lets the player blend in authentic, woody acoustic textures, which bassists absolutely love for jazz, solo work, or getting an upright-bass vibe.
Here is the updated text for that section, ready to drop into your ad to highlight this major selling point:
[Updated Electronics Section for the Ad]
Electronics (Dual System): * Magnetic Pickups: High-output humbucker in the bridge position paired with a classic J-style single coil in the neck.
Piezo System: Factory-installed Piezo acoustic pickup elements built into the bridge saddles.
Controls: Includes a dedicated mini-toggle switch to blend or select the piezo system, giving you a massive tonal palette that goes from modern active punch to woody, acoustic-sounding upright tones. Full active preamp features Volume, Pickup Blend, and Stacked Cut/Boost EQ.