Gibson posting specs.

[Mike Sulzer]

Why can't the resonant frequencies be those of the pickups alone? I measure them with an LCR meter where the L, C, and R are all insignificant compared to those of the pup. I'd be surprised if one of the worlds largest pickup manufacturers didn't have access to similar equipment.

Here are a couple of measurements of Gibson pickups.
#8

The method used is described here and in references contained in it.

Software for performing pickup analysis with a recording interface.

[Mike Sulzer]

No, NO, I mean "Gibson inspired".

Here are a couple of measurements of Gibson pickups.
#8

The method used is described here and in references contained in it.

Software for performing pickup analysis with a recording interface.

[Tony Bones]

A resonant frequency of about 3 KHz is achieved with the cable capacitance of a few (but how many exactly?) hundred pfs in parallel with the pickup. The resonant frequency of a PAF type of humbucker alone is more like 12 KHz. (The effects of eddy currents have raised that a couple of KHz.) You have a few Henries and the capacitance of the two coils in series is about 70 pf. There is no way that can be 3 KHz.

I see. 3kHz is too low to be the pickup alone. Makes sense. Thanks.

Using a meter is tricky. At 100 Hz measurement frequency you get the coil capacitance. At 1 KHz you get a somewhat different value from eddy current effects. You need to use a much higher frequency to get the capacitance.

The meter (an Agilent E4980A) will take 200 measurements over whatever range of frequencies I choose. The resonant frequency is where the impedance is purely resistive, no? I mean, that's the definition, but is there something more practical that I'm missing?

[Mike Sulzer]

That is certainly the most reasonable definition of resonance. The thing to remember is that in general, a pickup with steel cores has, in addition to the series resistance from the winding, a loss in parallel from coupling to the cores (so called eddy current losses). Thus measurement at a single frequency, which provides two numbers, real and imaginary, cannot be directly interpreted as two circuit elements. It can at low frequencies where eddy current losses are negligible. Thus at 100 Hz the meter gives an inductance and a series resistance. It should at very high frequencies as well, since eddy current losses are also expected to go to zero since the leakage flux is like a series inductor. (Note that in a pickup, unlike a transformer, we are not intentionally transferring power from "primary" to "secondary".

Does your Agilent give sensible capacitance measurements on a steel core pickup at high frequencies? You might have to go well above 20 KHz to get this to make sense.

I see. 3kHz is too low to be the pickup alone. Makes sense. Thanks.



The meter (an Agilent E4980A) will take 200 measurements over whatever range of frequencies I choose. The resonant frequency is where the impedance is purely resistive, no? I mean, that's the definition, but is there something more practical that I'm missing?

[Tony Bones]

Does your Agilent give sensible capacitance measurements on a steel core pickup at high frequencies? You might have to go well above 20 KHz to get this to make sense.

Good question. It's a seriously expensive piece of equipment, but no magic. All it can do drive a sine wave and measure voltage, current, and the relative phase. The conclusions that it comes to are not necessarily meaningful.

I will have a couple of melody maker pickups to look at in a couple of weeks (not that there's anything about them that I'm anxious to understand.) I'll pay close attention.

[eschertron]

It's probably a good time to reiterate that a specification is neither a manufacturing process nor a business plan.

While it is unusual for a big player to be so forthright, the rest of the pickup industry has been so for years. Gibson ups the ante by publishing a windings count, etc. Compare this to Lindy Fralin's site info in which he offers custom builds of by form factor, windings, magnet type, and so forth.

A more nuanced reading is that Gibson just told the boutique industry

1) rewind/repair specs, and
2) how to differentiate itself from OEM offerings.

And, regardless of specifications disclosure, if Gibson buys their pickups from China, it won't be long before same-factory knock-offs hit the market.

Yeah, I can see it: some guy loitering on the corner outside Sam Ash's NYC shop sez,
"Psst. You. Da guitah playuh. Got a 57 Classic heah fuh t'ree Jacksons."

So I see it as a business strategy: given that the knockoffs are so prevalent, and that Joe on the street can't tell a Gibson from a forgery; it is better that Joe - playing his imitation Gibson, and thinking that he has an authentic one - gets as close to authentic an experience as he can. In other words, Gibson is protecting their image and credibility by ensuring that all the counterfeits are as good as possible.

[12xu]

Any of the newer Custom Buckers I've tried in the Historics have been really nice sounding. I also liked the BB 1&2 when they first came out, the unpotted ones that were in the historic for a year or two...pretty sure they've changed them over the years.

I'm not sure why they still put junk like the 498, 500 in some guitars...those things are horrible IMO.