Bass Mods 3 Band Preamp 4 Controls Active Passive BEQ12-34AP. Preamp is in great condition and works just fine! Sounds great! All you do is hook up your battery wires battery wire included and your pick ups and start playing!! Pull the volume pot for passive mode, push for active. I had this preamp in my franken-jazz bass using Aguilar 4J60 Pups. This preamp can also be used in a P Bass. The diagram is the same regardless. There is also a gain control on the preamp. Preamp Controls are: 1. Volume Push Pull Active/Passive 2. Balance Control 3. Mid 4. Treble/Bass stack Price is $55.00 shipped. CONUS Only. Paypal Only.