GFS Professional Series Alnico II humbuckers
You can buy them from GFS HERE
I really like these pickups. I have a pair (zebra - no covers) installed in a bolt-on mahogany neck flamed maple cap/alder-bodied semi-hollow guitar I built. Originally I had a GFS VEH ("Vintage Extra Hot") in the bridge, but the tone didn't do it for me (subject of another review). To me GFS at it's best hits a sweet spot - a good selection of different pickup-types to experiment with without breaking the bank. Sometimes you just don't know if you are going to like a sound until it is in your guitar with your amp, and GFS can get you a new sound for short money - something I think everyone can appreciate.
Now these pickups used to be unpotted. Now if you check out the GFS site it says "All of the GFS Professional Series pickups are individually potted in a Beeswax/Paraffin mixture to insure squeal-free performance". I have the older, unpotted version, but haven't had any issues with squeal myself. It literally has never happened, at a variety of gain and volume levels.
In terms of the sound of these are really bright, articulate, and "organic", for lack of a better way of saying it. They are, for me, my go-to pickups for classic rock and blues neck tones (even moreso than the BG Pure90s for me). I have a very nice Joe Till handmade semi-hollow flamed-maple carved-top guitar with the Seymour Duncan Jazz/JB combo and I've thought about swapping those pickups out for these. I do really want to get my hands on a SD Seth Lover set as well, as I imagine they would be similar tone-wise and I wonder which I'd like more. If you like the more articulate vintage-sound of older humbuckers, especially Alnico II, it is worth $35 to see if you like these.
Side note: With GFS you cannot get wider string spacing trembucker-style pickups, so if you prefer a wider bridge setup (as I do) note that you will want to take extra care that the poles are as aligned under your strings as possible. I also raised up the screw on the high E string to give me back a bit of that string's output - worked great.
From the manufacturer:
"Here's our best, most authentic take on the classic late 50's Humbucker sound- The KMZII professional Series.
The great warm, woody vintage sound of Les Pauls, made in KalaMaZoo. Made with all the good stuff- genuine Alnico II bar magnets, hand magnetized and assembled with the correct vintage geometry German Silver non-magnetic baseplate and correct vintage Steel braided leads with push-back cloth center lead.
We've wound these to match a fabulous sounding set of early Gibson humbuckers- ...wound really vintage- 8.6K for the bridge and 7.6K for the neck. You'll get extra warmth, ridiculous clarity and chime, and that great sweet notchy midrange that only Alnico II can give you.
The KMZII comes packed in a GFS Professional box with nickel plated Stainless Steel screws, mounted in a black trim ring, and complete with a wiring diagram."
Best videos/sound clips:
The first video is from GFS with Carlos Garcia V (LA-based pro guitarist) playing these in a Xaviere (GFS brand) single cutaway guitar. The amp used is a Fender Super Reverb and the mic is an SM57. The playing starts around 0:53. I find his tone mellower than some of the other videos/my own personal experience. This could be the guitar/amp settings or attributable to the metal covers on the pickups (which will always cut a bit off the high frequency response vs. an uncovered pickup). At 1:58 he changes to a Marshall JCM 2000 mic'd with SM57 and plays some GNR AFD style licks. Good video if anything I wish it was longer!
The second video is from GFS with Earl Slick playing these in a Xaviere (GFS brand) single cutaway guitar. The video is well recorded but the amp/speaker/mic combo isn't listed, unfortunately. Earl plays some midgain tones/licks here - I'll see if I can find a good clean sound in another video or post one myself later.
Matt Stottmann posted this review of the neck/bridge pickups in an Epiphone Sheraton II semi-hollow guitar through a Roland Blues Cube 1x12 60W with the EQ set flat. The mic looks like a Shure SM57. He plays the pickups clean, with drive, and then with backing tracks. Note that this is a solid-state amp so it may respond differently with gain than a tube amp (I've never played one). Starting around 6' he plays with a good amount of gain on some lead runs - I think across the board the pickups sound good. Note that since this video is from 2012 Matt likely has the unpotted variant.
So these are my favorite videos of this pickup on YouTube, but there are definitely more out there. Clink the following link if you want to launch a new window and auto-search for this pickup on YouTube HERE