Posted this before, but I'm coming from a little different angle. MIM P bass - tone all the way to treble side, volume 100%, I get hum, enough that I don't like it. Very audible. Have to go about 60% of the way toward low side of tone to get rid of it. Yamaha RBX250 w/ P pickup configuration - same test, I get WAY less hum. I have to listen close to detect it. P bass - If I touch the metal volume knob or strings or bridge, hum stops. I have tested resistance between bridge, each string, jack nut and knobs and there is 0.2 ohms max (probably the test leads!). I seem to be grounded. Jack is new, cap is new Sprague orange drop 0.047uf. Neither bass is shielded. My cable path to the amp doesn't hum with any other instrument. Is this just a characteristic that's present to varying degrees with every bass that I have to live with? Is it possible to have a dead quiet passive bass with tone all the way to treble? Is there a 'most common reason' for this hum? The reason for the hum is surely still there when the tone control is all the way to the low side, but it's just filtered out. Grounding is stock, not 'star'. Pots aren't noisy. Solar storm is passed and problem persists. Next idea is to re-do grounds in a 'star' configuration unless somebody has a different idea. Thanks!