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> Seymour Duncan Jb Vs Jbj Vs Duncan Designed Hb-102 Tech Specs
yoncopin
post Apr 14 2017, 05:41 PM
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This is my first test using my DIY pickup testing contraptions. I'm comparing the vintage Maricela Juarez wound JB (late 80s-early 90s), hereafter referred to as JBJ, with a modern Seymour Duncan JB and a Duncan Designed HB-102 (JB). I had hypothesized that they would all be technically the same, and I'm satisfied that they are with one caveat. The HB-102 has a nickel cover and I believe it is responsible for dropping the Q factor and flux density. The rest of the values are close enough for me to believe they're within production variances with little audible difference, which is also what my ears tell me. See this explanation:

"Generally speaking, when the resonant peak decreases in amplitude, which is to say, "the Q factor has dropped" or "the mountain has become shorter", it means the metallic component is imposing eddy current resistance upon the pickup, meaning the metal is conductive. Higher permeability will also increase the eddy current resistance, but it is only necessary that the metal be conductive. The more conductive and permeable the metal, the greater the eddy current resistance, and the shorter the mountain" will be. This is especially useful for testing the quality of cheap brass versus better nickel silver covers, and figuring out if an eBay seller has screwed you or not. Also note that any kind of series resistance in the circuit, and not just eddy current resistance, will also lower the Q factor. Resistance that is parallel to the pickup also lowers the Q factor, but in that case, a lower resistance lowers the Q factor, and higher resistance increases it."

Here are the technical measurements I made:

Resonant Frequency
JBJ: 4.7kHz
JB: 3.8kHz
HB102: 4.6kHz

Inductance
JBJ: 9.98H
JB: 10.58H
HB102: 10.72H

Capacitance (*calculated)
JBJ: 113pF
JB: 166pF
HB102: 112pF

DC Resistance
JBJ: 15.8k
JB: 16.3k
HB102: 15.7k

Flux Density:
JBJ: 300-400
JB: 300-400
HB102: 250-350

Unloaded Resonant Frequencies


Seymour Duncan JBJ


Seymour Duncan JB


Duncan Designed HB-102


This post has been edited by yoncopin: Apr 15 2017, 01:30 AM


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Mertay
post Apr 14 2017, 06:01 PM
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I think the resonant freq. between the JBJ and JB can be considered a notable difference if not critical. As the market demanded for tighter dist. , it makes sense they tweaked the JB a bit.

A PU cover definitly makes a sound difference but I wouldn't expect it to flatten it out biggrin.gif


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yoncopin
post Apr 14 2017, 07:29 PM
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Maybe it is, I'm still new to this myself. Maybe I'm just looking to find the answer I think it is. We'll see as I do more of these and how varied different models can be from each other.


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Gabriel Leopardi
post Apr 14 2017, 09:00 PM
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I find this comparision really interesting and I'm really curious to see this applied to more models. I personally use JB and I've compared it with Duncan designed pick ups. I can say that this graphic materialize what I was feeling when comparing both.

Keep this stuff coming!


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yoncopin
post Apr 14 2017, 09:55 PM
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QUOTE (Gabriel Leopardi @ Apr 14 2017, 03:00 PM) *
I find this comparision really interesting and I'm really curious to see this applied to more models. I personally use JB and I've compared it with Duncan designed pick ups. I can say that this graphic materialize what I was feeling when comparing both.

Keep this stuff coming!


Glad you liked it! Can expand on what your feelings were and how the charts reflected them? I got a bunch of broken Dimarzio rails pickups that I fixed and am planning to do next.


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klasaine
post Apr 14 2017, 10:38 PM
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Excellent thread!

Slightly tangential but pickup guru Ron Ellis discovered that the pickup manufacturers don't/didn't always check the actual alloy content in the magnets that they ordered, never mind copper content in the wire. And he found upon ordering a bunch of different alloy mags from different sources as well as checking existing pkups in guitars (vintage and modern) that their alloy content/ratio varied - sometimes wildly. In some instances there was actually no 'Co' (cobalt) in the alnico.

Ron Ellis - https://www.google.com/search?q=ron+ellis+p...n+ellis+pickups
Vid interview with Ron Ellis. It's a bit rambling. Skip to 18:11 - http://www.mylespaul.com/forums/showthread.php?t=370455

This post has been edited by klasaine: Apr 15 2017, 02:25 PM


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yoncopin
post Apr 15 2017, 01:27 AM
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That was a great interview, I love the approach, more sophisticated than mine but in the same vein. It's actually very timely because I also ordered a bunch of different magnets (A2/5/8 & ceramic) to experiment with magnet swapping. I really like breaking things down to see what actually makes a difference. There's so much anecdotal info out there I just had to try it all myself smile.gif


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Todd Simpson
post Apr 15 2017, 02:52 AM
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I really love ALNICO mags on Bridge pups over ceramic but that's just me smile.gif So I'm very curious to see how your test come out. I love the ALNICO 8 mag most of all as it has the best bits of alnico and much of the gain of ceramic. The CRAZY 8 pickup is the best things I've tried. Sadly, it got sold with the guitar I bought it for. BC RICH GUNSLINGER, which had CRAP pups to start. Good pups can really change a guitar. smile.gif



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Mertay
post Apr 15 2017, 08:31 AM
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QUOTE (yoncopin @ Apr 15 2017, 12:27 AM) *
It's actually very timely because I also ordered a bunch of different magnets (A2/5/8 & ceramic) to experiment with magnet swapping.


Don't forget rough cast alnico! smile.gif



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