It's in the reviews-section:
viewtopic.php?f=16&t=1440 
They're two completely different beasts, sonically. My '83 with the Super P5/J5 is a very versatile bass which will handle anything from a Precision growl to a hifi slap tone. The '81 with the Super 4's has more personality of its own. It's brighter, has a nice and agressive highmid growl (actually, it can almost get down to a gnarl). The '81 is my favourite because it really has a character all of its own, but I play the '83 more often because it fits in everywhere
In the comparison, I wrote:
Quote:
The 1981, with its Super 4 singlecoils with large MM-like exposed pole pieces, sounds bright and articulate. The neck pickup soloed sounds big and woody but retains a lot of definition and clarity with plenty of mids. The bridge pickup soloed sounds fairly weak and thin, but adding some bass on the onboard EQ beefens up the tone for a nice Jaco-like growl. The middle switch position produces great tones for both fingerstyle, pickstyle and slap. The preamp is remarkably natural-sounding and adds almost no colour to the tone when the bass is switched from passive to active, and the EQ is very effective. The preamp gain pot is very clever, and has a center indent. In the center position there is absolutely no increase or decrease in volume when switching from active to passive. The gain pot enables you to setup an EQ preset, and boost and cut the overall level so you can switch between two different tones. The overall tone is harmonically richer in active mode though, so I rarely play it in passive mode.
The 1983, with its PJ-style pickups, produces a more balanced tone and is more versatile than the 1981. The neck pickup soloed indeed sounds very similar to a Precision Bass, and is remarkably quiet. The tone is a bit tighter and more refined than that of a real Precision though. The bridge pickup soloed, being placed very close to the bridge, again sounds a bit thin and weak. It's warmer than the bridge pickup of the 1981 though. It's not nearly as quiet as the neck pickup, a constant hum is audible when you're not playing. In the inbetween positions of the balance pot this hum is still clearly audible, but quieter than the bridge pickup soloed.
