J Mascis signature Jazzmaster pickups

[timtam]

I got mine as well. A quick heads up; the DC resistance ratings seem to be slightly off for the bridge pu. Mine measured differently than the values given on the package (granted , my voltmeter could be inaccurate)

Neck: 7.14k (marked 7.27k)
Bridge: 6.92k (marked 7.31k)

I will probably install these in my FSR JM to compare/contrast to the old CV JM (PV65s) as well as the JMJM (P90-ish).

Fender quotes +/- 10% variability on their DCRs (although the only place you see that mentioned AFAIK is in the FCS Design Guide, where both machine-wound and 'hand-wound' DCRs are "+/- 10% "... so it's possibly more of a 'covering our ass' figure than a true reflection of likely variability). In any case yours are well within spec. DCR will also vary with temperature. All the more reason why their quoting DCR to 2 decimal places is stupid.

[bankyVee]

Thanks for the clarification. It's within the the +/-10% for DCR. Does anyone know how to measure the inductance?

Just from observations, you can definitely tell these have more copper wire winds than the stock cv or PV65 pickups. Not as many winds as a Novak JM-V.

[andy_tchp]

How could you 'definitely tell' without unwinding them and counting?

[timtam]

Thanks for the clarification. It's within the the +/-10% for DCR. Does anyone know how to measure the inductance?

Just from observations, you can definitely tell these have more copper wire winds than the stock cv or PV65 pickups. Not as many winds as a Novak JM-V.

Recommended inductance test procedure is the DE-5000 LCR meter or similar meter testing at 100Hz or 120Hz (there are cheaper ones around but with uncertain specs). Although AFAIK Fender has never described exactly how they measure inductance. It's a pity if these pickups don't have inductance figures on the box or the product page like the PV65's do (3.2H, 6.8 kOhms DCR).
https://www.youtube.com/watch?v=lHYsQGK5PoY
http://www.planetz.com/wp-content/uploa ... hnique.pdf

[SixStringSlinger]

Thanks for the clarification. It's within the the +/-10% for DCR. Does anyone know how to measure the inductance?

Just from observations, you can definitely tell these have more copper wire winds than the stock cv or PV65 pickups. Not as many winds as a Novak JM-V.

Recommended inductance test procedure is the DE-5000 LCR meter or similar meter testing at 100Hz or 120Hz (there are cheaper ones around but with uncertain specs). Although AFAIK Fender has never described exactly how they measure inductance. It's a pity if these pickups don't have inductance figures on the box or the product page like the PV65's do (3.2H, 6.8 kOhms DCR).
https://www.youtube.com/watch?v=lHYsQGK5PoY
http://www.planetz.com/wp-content/uploa ... hnique.pdf

Fender's website lists it as 3.6h for the neck and 3.7h for the bridge.

[timtam]

Fender's website lists it as 3.6h for the neck and 3.7h for the bridge.

Ah ... so it does. Not sure what I was looking at earlier today. And in fact I even quoted their inductances earlier in the thread ...
viewtopic.php?f=6&t=124057#p1752843

With nominally equal DCRs according to the published specs, and quoted inductances that differ by only 0.1 (too small to have been deliberately designed to be that way), it's a fair assumption that neck and bridge are the same pickup, just with different magnetic polarity (for a RWRP pairing) ... ie just like neck/bridge PV65s are the same.

[SixStringSlinger]

Fender's website lists it as 3.6h for the neck and 3.7h for the bridge.

Ah ... so it does. Not sure what I was looking at earlier today. And in fact I even quoted their inductances earlier in the thread ...
viewtopic.php?f=6&t=124057#p1752843

With nominally equal DCRs according to the published specs, and quoted inductances that differ by only 0.1 (too small to have been deliberately designed to be that way), it's a fair assumption that neck and bridge are the same pickup, just with different magnetic polarity (for a RWRP pairing) ... ie just like neck/bridge PV65s are the same.

Slight tangent: All other things being equal (or near enough), would a higher or lower inductance result in an audible difference?

[Embenny]

Slight tangent: All other things being equal (or near enough), would a higher or lower inductance result in an audible difference?

Absolutely. Inductance is the major spec you can measure on a test bench that has a direct correlation to the way a pickup sounds.

When people talk about "hot" pickups with high DC resistance, what they're actually trying to refer to is a high inductance pickup. That's because, if you keep the magnet structure and wire gauge the same, more turns of wire equals more inductance. Higher inductance means higher output and a lower resonant frequency.

But the number of turns of wire isn't the only thing that changes inductance. Wire gauge changes it as well. Changing the polepiece material (e.g. alnico poles vs steel poles vs ceramic poles), and even the polepiece shape (bar/rail vs rod) all affect it.

That's why DCR is a terrible surrogate for inductance. It's not the only spec that matters to the tone of the pickup (the magnetic circuit shapes the attack of the notes, and things like metal baseplates and covers mitigate the high end and Q of the resonant frequency via eddy currents), but it's the single most important spec. If you want a loud pickup with a prominent midrange, you want a high inductance pickup. If you want a quieter pickup with a prominent high end, you want a low inductance pickup.

Edit: typo

[bankyVee]

Thanks for the clarification. So many yt pundits give the shorthand evaluation about having a "hot" pickup in the bridge solely based on DCR but forget to take the type (single, humbucker) or structure. The values can vary wildly from different sets and there is so much more involved with regards to tone.

How could you 'definitely tell' without unwinding them and counting?

I can tell from a visual in hand inspection. These pickups are heavier and the windings are wider in the bobbin. I don't have an exact stat but I'd estimate these are anywhere from 25-33% heavier than the stock pickups and PV65s. Granted, some of that mass may be accounted for by the wax potted poles and wire. Novak's have the most visible difference because the copper windings are almost over the edge of the bobbin.

[Nevets]

I will probably install these in my FSR JM to compare/contrast to the old CV JM (PV65s) as well as the JMJM (P90-ish).

Nice. Looking forward to hearing your thoughts on them. I'm planning to do the same with my FSR CV JM.

[marginwalker]

Just got mine in the mail!

Here are some pics

Awesome!!!! Thank you!!!!!

Are the bobbins grey or black? Look grey, either way I’m happy.
Let us know what you think when you get them in.

Yep they are grey!

[andy_tchp]

How could you 'definitely tell' without unwinding them and counting?

I can tell from a visual in hand inspection. These pickups are heavier and the windings are wider in the bobbin. I don't have an exact stat but I'd estimate these are anywhere from 25-33% heavier than the stock pickups and PV65s. Granted, some of that mass may be accounted for by the wax potted poles and wire. Novak's have the most visible difference because the copper windings are almost over the edge of the bobbin.

Perhaps I was too subtle.

That 'visual in hand inspection' assumes the exact same wire type, bobbin spacing, winding techniques and raw materials.

Wire gauge, insulation type (ie formvar/enamel/polyester/nylon/... which also affects the overall wire diameter even when wire is the 'same gauge'), winding pattern and tension on the wire while winding will all play a part in determining where the windings end up compared to the edge of the bobbin.

The 'wire stuff' mentioned above (these things are definitively not all equal) and magnet metallurgy will also come into play regarding the overall weight, which is assuredly the most meaningless metric of an electric guitar pickup (outside any exercises in building ultra lightweight instruments, which is something I can get behind...)

[nashmaster]

Just got mine in the mail!

Here are some pics

Awesome!!!! Thank you!!!!!

Are the bobbins grey or black? Look grey, either way I’m happy.
Let us know what you think when you get them in.

Yep they are grey!

Have you installed them yet? So curious to hear how they sound!

[sugarandopium]

https://youtu.be/sIJYvkejS9A

Very good review done here.

[marginwalker]

Awesome!!!! Thank you!!!!!

Are the bobbins grey or black? Look grey, either way I’m happy.
Let us know what you think when you get them in.

Yep they are grey!

Have you installed them yet? So curious to hear how they sound!

Not yet, they’ll be going in a partsmaster I’m putting together!