Also consider the setup of the bass, and where he plucked the strings. He used the standard Labella set of the day (there was only one gauge available, which would be considered "heavy" by any standards), and the action was set quite high. I suspect the neck had a bit of a bow in it, lol. He also had both covers on his bass. He rested his third and fourth fingers on the pickup cover, and plucked with his first finger. His second finger saw little if any use. Consider what this means. He plucked the string BETWEEN the fingerboard and the p-bass pickup. How many of you do that? Few if any I bet. That, plus the heavy (and dead) strings, and the rubber mute (OVER, not under) the strings, would be a good starting point of you want a bass set up like his.
The "Jamerson" set that Labella sells is a set that I used for many years, back in the 70's/80's. I know it well. They are VERY bright when new, and will sound NOTHING like his set. One time I broke the G string while doing some maintenance on the bass, and was supremely dismayed at the mis-match of the new G string. I lent my bass to a friend for week, who ate lots of peanut butter and rarely showered. That helped a lot
Amp settings will not get you there. Neither will round wounds, as they have little if any "thud" at the start of the note, which is important if you want to go for the 60's thing. The rubber is important in order to facilitate the rapid decay. Jamersons bass has a decay almost as fast as a conga drum. That is not the strings, nor the age of the strings, it's the rubber. All these factors are important, but without the rubber mute, the bass will still ring too much.
The Labella set was the heaviest available in it's day (and probably still is). The only other string widely available then was Fender, which had an E string that barely spoke. And the A was not much better. You kinda HAD to move to Labella if you weren't satisfied with what came on the bass. But they were monstrously heavy, and not for the weak at heart. Putting those on your bass now would be very hard for most players, and very hard on most basses. In my opinion, the Pyramid Gold flats sound more like Jamerson did than a new set of Labellas will. They are a "rope core" type of string, with internal damping built into the strings itself. I have them on my '63 P bass (that I bought back in '74), and there is no doubt in my mind that they nail that sound better than a new set of Labellas will, UNLESS I played them full time, ate lots of fried chicken (and never washed my hands), and was willing to wait a few years.
BTW, I'm 55, and played that Labella set for at least a decade and a half on a '63 P bass, so that's my reference point
