Following on from my recent TMI Custom JRS SB75 build I had mentioned how I would write about these unique Mosrite pickups that only appeared in the rare "slab body" Mosrite Ventures model II from mid 1965. I've written volumes about these particular guitars and Mosrite in general, but I'll outline what made these pickups so unique and special in the Mosrite world.
These were introduced on the "student model" Mosrite in mid 1965 and were an attempt to make a cheaper, simpler pickup for the expensive Mosrite line. While the basics of this pickup would carry over to the production non pole piece pickups of the later German Carve Mk II/V and some Celebrity models, the thin version here was only available in the early Mk II.
My Wosrite series used Mosrite style pickups back in the late 90's/early 2000's but I stopped making guitars for about 10 years and packed the winder away as time started to be at a premium. I started making guitars again in about 2017 so I needed to make pickups for my new TMI series guitars and dusted the winder off and dove back into the world of fine wire wrapped around a magnetic field.
Semie favoured a segmented bar magnet that he had started buying around 1962/63 which was an industrial magnet that could be broken or snapped to length to use in many applications. Because his pickups were based on the P-90 design he needed 2 matching magnets to run down each side of the pole pieces on the bottom of the bobbin. It's unclear exactly what material and/or alloy these magnets are but as I've said in the past, to my ears, A2 or A3 sounds closest with all else being equal. As I've also said, I personally don't think the segments make any difference to tone but I had some made for my pickups to keep the nerds happy.
Because the new Model II was going to be a student model it didn't have the distinctive (and expensive) German carve or any binding like its big sibling. It had a new cheaper folded steel vibrato and a non-roller bridge and of course, these new pickups with less parts. All of these new features, including plastic button Kluson tuners were designed to make the new model competitive with other student models from people like Fender and Gibson.
So Mosrite didn't have to buy new parts for these pickups they simply took 2 of the segmented magnets used in the more expensive pickups, stood them vertically with a thin piece of timber (a maple offcut from the necks) between them and glued this assembly together with thin clear plastic hand cut flatwork top and bottom to form a rudimentary bobbin.
The magnets were wrapped in medical tape to stop the metal rubbing off the wire insulation and the "bobbin" was wound with #43 wire to give an output of approx. 12K and then the whole assembly was epoxied into hand formed covers with a white high-density foam. This was how the initial batches of the original Mosrite Ventures models were also made in 1963/64 before they started getting die cast covers made.
Like the bigger pickups these got a simple aluminium bar glued to the bottom when the whole assembly was being made and these had a small hole drilled in each end for the pickup height adjustment screws. Lead wires on all 60's (and some later) Mosrites are a thin stiff multicore black and white wire sometimes twisted together. The original pickups were not potted, except in epoxy (later dental putty) for assembly and some older Mosrite pickups, including these can be quite microphonic.
These are pretty unique sounding pickups in both the Mosrite world and the world of guitars in general. I don't personally know of any other manufacturers who made single coils exactly like this and they are integral to that early Ramones tone. While the later big version Mk II/V pickups get very close and of course if you want the post late 1979/80 tone, you'll need a DiMarzio FS1.