I got a used Lakland Joe Osborn with J-Retro01 Deluxe. I assume the guy fitted the preamp himself as the output is in a very bad place. I was think of removing the passive pot in order to put the output jack back, so that I can actually play the bass in standing position. I won't be needing the passive tone option. Is there a way I can solder this? Opening the bass guitar I discovered that it says "E-Pro NOV/03-1174" on the preamp.