A .001 mfd capacitor soldered to the bass-cut pot (center lug to back of pot) of an L-1500 bass will provide plenty of low-end heft all the time.
The L-2000 and ASAT models come with the same capacitor.
When the L-1500 model was developed (from the Climax bass, which replaced the L-1000 in 1991) it was omitted to provide a more 'aggressive' tone.
Adding that capacitor gives an L-1500 bass big balls - enough to go toe-to-toe with a Stingray or Sterling or Dimension strung with any strings.
Yep, I've had the cap sitting here since I read about the mod. After I install it I'll A/B it against an L-2000, a Sterling H, and a few other similar basses just for kicks.
I expect an improvement to the L-1500 with the cap mod, but I don't expect it to have the authority of an L-2000, or even an L-1000. I'll be happy if the L-1500 becomes more usable. In its current state it's borderline, but otherwise it's an excellent example....lightweight, ebony board, quartersawn neck, and dead mint.
Will post impressions later for any interested parties. Cheers.