Tascam Basstrainer CD BT2

[fluffo]

I use mine a lot weather it be learning songs and being able to slow down or loop or just for practice.
My problem is with a passive jazz bass you get a massive earth hum.
I've get a couple of passive Jazzes and I've owned 2 basstrainers and used different headphones but still get this issue.
Anything active is fine and does not have this problem.
Any suggestions on getting round this, It is reduced some what if you roll the tone right off but not ideal.

[Telebass]

The trick as always with a jazz bass is to keep the volumes at equal levels. When set equally, the set as a whole is humbucking (or should be if wired right). Either pickup soloed produces the most hum.
Additionally check around you for sources of excessive mains noise, fluorescent lighting, anything with a motor in it, old CRT pc monitors, etc.

[NGLCALN]

Answer to Telebass, posted 5/26/15,   I own 2 Jazz basses, a '78 and a '18. Both have that inherent problem of a bad hum when either volume is not up all the way. This drove me nuts on stage as I like to use that balance to fine tune the tone. I replaced the pick ups in both with Aguilar passive humbuckers, problem solved