jfh4242 wrote:Where does one usually start with this?
By asking questions. Like:
Under what conditions do you hear the hum? Touching nothing on the bass? Touching the strings? Touching the bridge?
Is it a true hum, which is about a low B on the A string?
Are there any notable high frequency sounds coming through as well as the hum?
Concerning pic number two, the protruding thing on the right was touching the male end of my quarter inch wire when plugged in...is that ok? I imagine so, because it seems to be keeping the quarter inch wire inside.
That would be the "TIP" connection of the jack. It is supposed to be in contact with the "TIP" of the plug; that "quarter inch wire" you speak of.
How many connections should there be to the input jack? I notice that my bass has one, that white wire. Is that ok? Thanks!
There should be two connections to the
output jack. One of them would be the white wire, as shown. The other would be a ground connection. In your bass, the ground connection can be done a couple of different ways: (1) A wire lead from one of the pot cans to the ground lug of the jack or (2) Physically mounting the jack to the grounded foil on the back of the pickguard, which can be quite problematic.
Based on your second image, the jack is not grounded or has a poor connection to ground. Whoever wired your bass used method two. In an of itself, this is generally workable so long as the jack
never rotates in its mounting hole. When rotation does occur, which is all too often, the connection to the grounding foil wears through. Over time it gets worse and worse until the foil is worn through to the underlying plastic of the pickguard, at which point the jack no longer has a good ground connection. Because the jack is a key component of grounding and is no longer in contact with ground, the instrument has an open ground and hums.
Look carefully at the underside of your jack and you'll see that what I described above is what's happening. The jack has loosened and spun in its hole and has been repeatedly spun back down to tighten on the pickguard. This cycle has repeated enough times to wear through the foil to the point that the physical connection to the foil is compromised.
The fix is to (A) tighten the jack so that it can no longer spin in its mounting hole, then (B) solder a short green or black lead from the free solder lug on the jack to the back (can) of one of the pots.
This is, of course, an Internet diagnosis/eval. It's worth every penny you paid.
Ken...
