Not J, but I feel kinda qualified to answer with a solid yes. Great sounding preamp.Hello, hope you don't mind me tacking onto this thread, but I have a '77 jazz with Sadowsky single coils pups that I love, except for the hum. Would you 2-band J core be a good fit for that configuration?
Note that the J Core won’t fix a hum problem caused by poor shielding or miswiring. In fact, it might be wise to have the bass checked for proper shielding before you spend money on any more electronics.