....and here's some more specific info I dug up:
a Guild Starfire bass that was later altered by Alembic Instruments. Dubbed the "Godfather," it has three Alembic pickups a quad pickup with four outputs (one for each string) and standard bass and treble humbuckers. The bottom half of the instrument is crammed full of electronics, while the top half is loaded with foam rubber to damp the resonance of the body to eliminate feedback.
Today the "Godfather" is Phil's spare. His main bass is a custom-made Alembic with additional circuitry designed by George Munday of Pluto Electronics. Phil also uses George's tone-modifying Pluto Pedal, an active filter/boost/cut unit in which two filters can be swept at once. Phil likes it because of its versatility for bass tone modification. Nevertheless, he complains that too many pedals only perform one or two functions. "I still have a dream of a computer-controlled synthesizer/quadraphonic bass," he says, "and the instrument I'm playing now has the capability of being that. All it needs is the proper interface."
[FONT=Courier New, Courier, mono]The Alembic has the same pickup configuration found on the Guild: two standard humbuckers and a quad. Though he can get a separte signal for each string, Phil currently is running his signal monaurally. The filters on both the Guild and the Alembic basses allow for 32 tone settings, with a mixing of filtered and flat response signals from the pickups. The filter modules contain controls for Q (resonance), bandwidth, frequency reponse, and filter mode (to allow for lowpass, bandpass, highpass, and notch filtering). The filters are essentially Phil's design, though Alembic built them, and George Munday redesigned them to Phil'specifications.[/FONT]
[FONT=Courier New, Courier, mono]His favorite tone settings center around the use of the bandpass filter, though he explains that he generally just tries to blend well with what the other musicians are doing. He usually plays with a pick, though on extremely rare occasions he uses his fingers. The Fender Heavy he has relied on for the past few years replaced a Carpe Plexiglas pick he favored until its manufacturer folded. His string choice is D'Addario Half Rounds, gauged at .045, .060, .075, and .090. He previously used Framus and Pyramid strings. He always puts on new strings before going into the studio to record, but on tour he changes them only as necessary.[/FONT]