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Post by antigua on Feb 3, 2018 20:40:36 GMT -5
 Mfg product link: store.gibson.com/p-94r-humbucker-sized-p-90-single-coil/ This is Gibson's "P-90 in a PAF footprint" hybrid pickup. It's as if a regular P-90 has been stretched downwards, to make the bobbin about twice as tall as it would be otherwise. The consensus on guitar forums has been that this pickup is not such a great P-90 stand-in, while some similar models from Seymour Duncan and Lollar get higher praise. So how close is this thing to a real P-90?? We shall see. I received this P94R with an Epiphone Lee Malia Les Paul. I swapped this pickup out because I felt it was too dark at the time, and while I have come to realize that P-90's are "dark" in general, due to a higher inductance coil of about 6 henries. I was hoping for clear clean tones more associated with lower inductance PAF replicas, which tend to be closer to 4.5 henries on average, and are brighter as a result. As can be seen in the pics below, the bobbin is much taller than that of a traditional P-90. This configuration puts more of the individual turns of wire further away from the guitar strings, and might slightly reduce overall output as a result. The moving magnetized guitar strings are the "action", and the closer a turn of wire is to that "action", the more voltage it produces. Due to the taller bobbin, the under-mounted magnets are also further away from the tops of the screws. I measured 350 gauss at the screw tops, which is just slightly less than the 400G I measured in the Tonerider Hot 90, which is a 'real' P-90 that also uses two AlNiCo 5 bars. The high permeability of the steel screws probably helps to mitigate the extra height of the coils, as compared to an overly tall bobbin with AlNiCo pole pieces, as less permeable AlNiCo does less to convey magnetic flux change up and down the core of the bobbin. The P94R is also wider than a typical P-90, though the added width of the P94R doesn't factor into the electromagnetic properties of the pickup. As seen in pictures below, the extra width mostly involves a wider frame, and a couple small wood spacers to hold the magnets in place, as a full sized wood spacer does in a PAF pickup. Here are the measured electrical values of P94R: Gibson P94R
- DC Resistance: 7.76K ohms
- Measured L: 6.21H
- Calculated C: 279pF (289 - 10)
- Gauss: 350G
unloaded: dV: 4.9dB f: 3.76kHz (red)
loaded (200k & 470pF): dV: 1.7dB f: 1.99kHz (blue) The loaded resonant peak of 2.0kHz and a resonant amplitude of only 1.7dB hits right in the general area of the other six P-90's I've tested, from Epiphone, and Tonerider 1, 2. On the high side I measured 2.3kHz, and on the low side 1.9kHz. As far as I can see, there's no reason these should not sound indistinguishable from a generic P-90. If the P94 has AlNiCo 5 bars, it might sound more like a P-90 with AlNiCo 2 on account of the slightly reduced magnetic strength at the strings. That taller bobbin might also reduce the output slightly, compared to a real P-90. The P94R will sound a lot darker, or "muddy" than the PAF's it generally replaces. The average PAF clone neck I've measured is 2.9kHz , so the P94R, and P-90's in general, are substantially darker on average, with loaded resonant peaks closer to 2.0kHz. The only thing that gives hotter P-90's and cooler PAF's some parity is that the narrower magnetic window of the single coil P-90 retains higher harmonics that would be lost to the comb filtering effects of a side-by-side coil type pickup, or "humbucker". In other words, a single coil pickup will always be a bit brighter because it retains higher harmonics better. It's difficult to say how much one compensate for the other without some laborious practical testing. Something that should be noted about the electrical values of the P94R, and other Gibson pickups, is that they include the 12" braided hookup wire, which impart about 70pF of added capacitance. This is partly why the overall capacitance is rather high at 279pF. I left the hookup cable in place since this is standard for the pickup. Another factor contributing to a high capacitance is the that the screws are grounded via the base plate, and so they capacitively couple with the windings of coil, where as a Fender style pickup's AlNiCo pole pieces do not. Fender also uses seprerate lead wires which capacitively couple to a much lower degree, and so altogether, you see a capacitance closer to 150pF for a similar type of Fender pickup. Differences such as a nickel silver versus a brass base plate have shown to only have a tiny effect on Q factor in both PAF's and P-90's, so it's surely a non issue in the case of P94 style hybrids. Pics:       |
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Post by wgen on Feb 5, 2018 9:44:54 GMT -5
Very interesting. Thank you very much...I read many threads about P94 type of pickups on the web, and it seems that, apart from Gibson, other manufacturers tried their own best formula of that "P90 in a PAF footprint" tone.
For example, the Duncan ones, which are called Phat Cats I seem to recall, seem to be wound with 43 AWG wire instead of 42 (note: this comes from the words about these pickups on various guitar forums, not actually really analysed and well-documented like yours are); it seems they might have done this choice to achieve a flatter bobbin than the Gibson counterpart overall, but with a similar DC resistance.
IF this really is the case, shouldn't we expect the Phat Cats to have less inductance and higher resonant peak than the Gibsons?
They also have a metal cover so it isn't that clear how that would add up, from the perspective of eddy current losses.
Other chinese examples, instead, seemed to just hide a sort of Telecaster bridge bobbin under the P94 cover, for a more jangly, twangy type of sound. Word is that, for example with GFS pickups, the "Mean 90s" are the true "P90s" formula, so I'd guess much like a Gibson P94 clone, while the "Dream 90s" would be the underwound, Telecaster bridge type of twangy tone.
Anyway, other manufacturers (I don't remember now which "boutique" maker in particular had published something about the "lousiness" of the Gibson claim to offer proper P90 tone with the P94s, but that's still around the web) pointed out that the P94s are not "the real thing" in some way or another. From your analysis, I also don't see how these couldn't somehow deliver, instead.
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Post by antigua on Feb 6, 2018 0:28:27 GMT -5
Very interesting. Thank you very much...I read many threads about P94 type of pickups on the web, and it seems that, apart from Gibson, other manufacturers tried their own best formula of that "P90 in a PAF footprint" tone. For example, the Duncan ones, which are called Phat Cats I seem to recall, seem to be wound with 43 AWG wire instead of 42 (note: this comes from the words about these pickups on various guitar forums, not actually really analysed and well-documented like yours are); The Phat Cats have a DC resistance of around 8k, so it's very unlikely that they used 43 AWG, as that would be equivalent to aboiut 6.3k with 42AWG, too little of wire for a P-90 tone. Lollar's "Single Coil for Humbucker" on the other hand has a DC resistance of 10k ohms and what appears to be a thinner bobbin, so I'm sure that is 43AWG. They also have a metal cover so it isn't that clear how that would add up, from the perspective of eddy current losses. Well there are covered "dog ear" P-90s, they use nickel silver I'd assume, so it's mostly a non issue. Other chinese examples, instead, seemed to just hide a sort of Telecaster bridge bobbin under the P94 cover, for a more jangly, twangy type of sound. Word is that, for example with GFS pickups, the "Mean 90s" are the true "P90s" formula, so I'd guess much like a Gibson P94 clone, while the "Dream 90s" would be the underwound, Telecaster bridge type of twangy tone. Anyway, other manufacturers (I don't remember now which "boutique" maker in particular had published something about the "lousiness" of the Gibson claim to offer proper P90 tone with the P94s, but that's still around the web) pointed out that the P94s are not "the real thing" in some way or another. From your analysis, I also don't see how these couldn't somehow deliver, instead. There's bias against Gibson in general. The 57 Classic gets a lot of unfair reviews, despite being a spec perfect P.A.F. clones. They love the guitars, but hate the company and its president. People's opinions are whimsical and seem to echo the popular sentiments. There's almost no discipline among guitarists in terms of blocking out extraneous influences. In fact they seek it out. |
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Post by wgen on Jun 7, 2018 4:06:59 GMT -5
Hello, I'd like to ask just a couple more questions about your great test and review of this pickup.
1) Do you think that the metal ring this Gibson pickup have around the edges is nickel silver or brass?
2) When you did the testing, did you have the metal ring around the edges of the pickup or did you put it aside..?
Thank you very much in advance!
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Post by antigua on Jun 7, 2018 21:11:57 GMT -5
Hello, I'd like to ask just a couple more questions about your great test and review of this pickup. 1) Do you think that the metal ring this Gibson pickup have around the edges is nickel silver or brass? 2) When you did the testing, did you have the metal ring around the edges of the pickup or did you put it aside..? Thank you very much in advance! I kept the ring in place for testing. I'm not sure if it's brass or nickel silver, but I'd guess the latter, since is a "USA" Gibson pickup. The ring/open cover won't cause much eddy current loss because there is a >5mm gap between the coil and the cover, due to the tall, thin coil in a wide PAF-sized housing. Even of the cover were brass, the effect would likely be minimal. |
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Post by wgen on Aug 9, 2019 3:37:38 GMT -5
Hello again, This message just for a quick link: markweinguitarlessons.com/forums/threads/new-wolfetone-p90-for-humbucker-route.74114/In this blog an interesting post of mr Wolfe of the renowned Wolfetone pickups, claims that Duncan phat cat have 43 awg wire, among other things. With a dc resistance of around 8k ohms, there's no way that phat cats were designed to achieve true P90 tone. Assuming this is true, it's a shame because I'd like a P90 tone with a humbucker size pickup and that shiny metal cover. Just an hypothesis here, isn't it possible that the nickel cover plus the Alnico 2 bars lower the peak and inductance enough to approximate the Gibson P94 response, which has no cover basically and Alnico 5, instead? Maybe I could opt for a Tonerider Rebel 90, instead..? |
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Post by antigua on Aug 11, 2019 7:11:27 GMT -5
Hello again, This message just for a quick link: markweinguitarlessons.com/forums/threads/new-wolfetone-p90-for-humbucker-route.74114/In this blog an interesting post of mr Wolfe of the renowned Wolfetone pickups, claims that Duncan phat cat have 43 awg wire, among other things. With a dc resistance of around 8k ohms, there's no way that phat cats were designed to achieve true P90 tone. Assuming this is true, it's a shame because I'd like a P90 tone with a humbucker size pickup and that shiny metal cover. Just an hypothesis here, isn't it possible that the nickel cover plus the Alnico 2 bars lower the peak and inductance enough to approximate the Gibson P94 response, which has no cover basically and Alnico 5, instead? Maybe I could opt for a Tonerider Rebel 90, instead..? I'm not sure how Wolfe determined that the Phat Cat uses 43 AWG. If the inductance were known, it would be immediately obvious. If they were $20, I'd buy one and figure it out, but I dont want to spend $80 just to figure it out. I really need to find a guitar shop that stocks a lot pickups and would be willing to let me measure their inventory. 8k of 43awg is equivelent to 6.16k 42awg as far as wire length goes, I'd expect the inductance of such a coil with steel poles to be around 3 henries, which would not be real P-90'ish. My bet would be that it does use 42AWG, maybe with a tight wound coil, or something like that. The AlNiCo 2 magnets would only increase the inductance by maybe a 100mH at best, a drop in the bucket compared to a 20% difference in overall turn count. |
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