Re: C5 more trebly than JB?
So much depends on the guitar and amp. Like a lot of former JB users, I've found the C-5 to be more pleasing to my ear. The one thing the JB does very well is lead tones on the high strings. That midrange spike makes the notes seem thicker.
The C-5 is more balanced from low to high, so it's a pickup that miraculously sounds great in almost every guitar I've put one in. It's got the tightest, most percussive lows of any of the Duncan Customs, but the rest of the frequencies resemble a 59B.
My opinion is that a C-5 with just a touch more mids would be the best Duncan I've ever heard. I asked Seymour how that would be possible, and he said "just overwind it a little, and that's it." After trying a Custom, CC, C-3, C-4, C-5, and JB, I'm convinced that all of them are SO close, but haven't totally nailed what I want to hear. If I get a chance to go to Santa Barbara, I may see if they can make a slightly overwound C-5 nickelcovered, which would put it right in between a C-5 and JB. Somehow, I've convinced myself that it may be the best A-5 humbucker for my taste, which is "hot/vintage"