Hi Guys! Just thought I'd throw in my .02 cents. Having been a Duncan dealer and a Fralin dealer and having owned quite a few 50's Gibsons with real paf pickups, including three 50's Bursts and at least three 50's 335's, I have considerable experience with vintage pafs and also Fralin and Duncan (and Tom Holmes) humbuckers.
First, no Fralin A4 humbucker I've owned and used in my own guitars had the sound and feel of a vintage paf. Lindy makes great pickups - but his A4 humbuckers do not get as authentic a vintage tone, IMO, as Duncans and Holmes pickups. Maybe all the old pafs I owned were either A2 or A5 because even when Lindy custom wound me a set of "vintage wound" humbuckers they did not remind me of the 50's pafs I've owned.
Second, this is a generalization, but I hear A4 as giving a humbucker some of the midrange personality of A2 and some of the bass and treble personality of A5.
In a way, A4 gives a humbucker much of the tonal quality of A5 but with more mids.
But A4 doesn't get that same smooth squawk and honk of a great A2 paf, and to my ears, if you're a player like me who wants his chords to be full, round and articulate, A4 neck humbuckers suffer from to much bass ( as do most A5 humbuckers) and can result in a muddy tone if you're playing loud and wanting a clear tone for chords.
In a nut shell, Alnico 2 humbuckers seem to have the tone and personality of the vintage 50's pafs I've owned - not A4 or A5. Which doesn't mean I don't like A4 or A5 - just that A2 gets the tone of the 50's pafs I've owned.
Lew
