Has anyone heard of this onboard pre amp.
 

I just got an old weird custom built bass as a present and I have found a 3 band pre amp in it. marked on the PCB as:
IN Yeon Industrial,Co.stp 001amp.
Anyone know anything at all about this pre amp?.
It is connected to a stingray 5 pickup of some description (probably Nordy?)
It seems to work ok and is very quiet signal to noise wise, I am just interested in trying to find out anything I can about this setup as I may want to modify its caps a bit, to bring down the frequency of the treble shelf band a bit as I would like it to pick out a bit more "clank" than "bing" if you know what I mean.:bassist: