Is a jumbo MFD single coil similar to a Jazzmaster pickup?

I just read in George Fullerton's book that the bobbins are wide and shallow. Isn't that like a Jazzmaster pickup? The pickups in my ASAT Special do sound quite similar to the overwound Fralin pickups on my JM.

I'd say not really. Jumbo MFDs are some of t he most cutting twangy pickups I've ever heard, with lots of output. On my ASAT I routinely roll the tone control back some to tame them. JM pickups are a little more mellow with their own thing going on. In the grand scheme of things, JMs, jumbo MFDs, and P90s are all in the same kind of ballpark, but they all have their own character. I'd say MFDs are closer to P90s than a JM pickup, but not the same as either.

I just read in George Fullerton's book that the bobbins are wide and shallow. Isn't that like a Jazzmaster pickup? The pickups in my ASAT Special do sound quite similar to the overwound Fralin pickups on my JM.

The Doheny G&L Magnetic Field Design™ jazz style single coils pickup is closer to the Jazzmaster pickup
but the MFD pickup uses ceramic magnets instead of Alnico magnets used in the JM pickup.
Also, the CLF Research Doheny V12 has G&L Magnetic Field Design™ jazz style humbucker pickups.
See this reference post: List of pickups used in G&L guitars.

Hope this helps.

While both are wider than a typical Fender-style single coils they are built quite differently. The magnets especially are different in both type and placement in the pickup.

I'd say not really. Jumbo MFDs are some of t he most cutting twangy pickups I've ever heard, with lots of output. On my ASAT I routinely roll the tone control back some to tame them. JM pickups are a little more mellow with their own thing going on. In the grand scheme of things, JMs, jumbo MFDs, and P90s are all in the same kind of ballpark, but they all have their own character. I'd say MFDs are closer to P90s than a JM pickup, but not the same as either.

I tend to agree. I've often said they're somewhat like 1/3 P90, 1/3 Mini-Humbucker, and 1/3 Tele single coil. They truly have a voice all their own.

I hear some similarity in tone. My Asat has the DFV which might push it more towards Jazzmaster tones. At least when listening to recordings Jazzmaster tones can be heard. That said I find the wide MFDs to be rather unique sounding p'ups.