It doesn't help that the Ric pickups are all wound in the same direction, and therefore not naturally hum-cancelling, as a split coil "P" type pickup is naturally.
You can get RWRP replacement pickups, but you could lose the "Ric-ness" of the sound. There is a way to reverse the polarity of the bridge pickup if you are electrically competent on TalkBass, but again, it's up to you whether you want to look at that as a solution.
Unfortunately, if you throw too much gain at a Ric, it can get a bit noisy, but they do sound awesome when they're just subtly overdriven.