Okay, this is probably a n00b question, but I figure I'd rather be corrected by the members of a technically-knowledgeable forum than by some bloke in a guitar shop
Recently I bought a Vox Custom four-string from a member here. I've had some difficulty with it because it only works with one of my leads. After some experimenting, I can now tell which leads won't work when I plug them in - the socket on the bass seems to pop the plug back out a touch (maybe half a millimetre). The one lead which works is a 6.35mm jack, mono. As far as I can tell it's the same shape as all the others. I've looked carefully at it and the other leads, and I can't see any difference in shape. I got it second-hand with another bass, so I have no idea whether there is anything exotic about it.
I'm a tad uneasy about this, because it seems to contradict everything I know about plugging the thing in, and because I've only got one lead which works.
The only thing I can think of which might explain this is that if I solo the P-pup, one of the switches on the bass lets me select the upper half of the pup, the lower half of the pup, or both. (That is, the top two strings, the bottom two strings, or all four.) That sounds as if it might be some sort of "stereo" selector, which I gather Rick basses can do (never played one, no idea).
Can anyone suggest what's going on, please? All advice gratefully received