I have decided to go back to passive on my J04 and JO5. I have two J-Retro - 01 preamps for sale. About a year old. In great working order. Modular quick connectors make for easy install. I put these in my JOs without any modification to the basses or the preamp. Mounting plates included. New online $250-$299. Asking $195 each - shipped US48. Paypal OK. $375 for both - shipped US48. Paypal OK. Both are all chrome - plate and knobs.