It would help if those describing their experience with the L500XL would say whether their experiences are with real Bill Lawrence or with the Bill Lawrence USA. The BL USA is much brighter than the original or the current Bill & Becky (Wilde Pickups).
I can't speak to the BL USA L500XL but all of the current versions (since 2005) of the Bill & Becky L500 indeed use Alnico V magnets. Here is come archived information about the real Bill Lawrence L500 pickups.
L500
L-500's (hard core, hi Q, blades, 15mm magnetic window). From February 2005: due to the unavailability of the ceramic magnets, a new circuit was designed using alnico V magnets, delivering the same sound.
The L-500 is a blade-style humbucker that can be retrofitted in both full-size humbucker and P-90/P-100 routs (see Dimensions post below)! The blades are 56mm/2.205" long, and will accommodate the string spacing of all known 6-string bridges (remember that the bridge pickup is not mounted at the saddles!).
L-500's are designed to deliver as much output passively whilst maintaining clarity and without sterility. If even higher output is required, EMG active pickups are recommended.
To deliver great tonal flexibility, the lead/bridge versions (L & XL) especially are recommended to be used in conjunction with the Q-Filter.
The L-500 comes in four versions:
C = 2.8 Henry
R = 4.8 Henry
L = 6.8 Henry
XL = 9.2 Henry
The XL requires at least 500K pots, whereas the other 500s can be used with 250K or 500K pots (all audio taper).
All 500's are extremely loud and therefore don't really mix well with other pickups. The XL without the load of the controls is ear-piercingly bright, but with a 500 kilo ohm pot loses about 50 percent of the higher end. With the EQ Filter [(Q-Filter)], you can gradually [effectively] reduce the inductance of the XL and get a tremendous variety of sounds.
The L with 250K pots is tonally voiced very similarly to the XL with 500K pots, but theres not quite as much punch. And if you employ a Q-Filter, theres not as much bandwidth to operate on, which means that the tonal variation that can be achieved is not as extensive as for the XL.
If you prefer the look of pole-pieces to blades:
For those wanting the more traditional pole-piece look, as opposed to the twin blades of the L-500's, the higher inductance L-600's deliver similar tone to their L-500 siblings.
