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anyone know about low impedance humbuckers?


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9/10/2004 12:38 AM
Jeremy F
anyone know about low impedance humbuckers?
i have my heart set on making a low impedance pickup for the bridge position of a new guitar body that i have just finished, which is made out of ash. I read that jimmy page's main guitar had a low impedance gibson pickup in the bridge position allowing him to get crystal clean chords and pristine notes. I have looked every where to find one of the pickups and have had no luck. And i can't afford the Jimmy Page Custom Les Paul, so i have decided to make a pickup if I can find out the info. Any help is appriciated.  
 
Jeremy
 
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9/10/2004 2:26 PM
anonymous
I think your information is either incorrect or misinterpreted. A true low impedance pickup would be an active one I believe and I doubt he uses one of those. I'm not sure of your source but likely what was meant by the term "low impedance" was a lower DC resistance of the bridge pickup with respect to his neck pickup.
 
9/10/2004 2:28 PM
Mike Turk

That was me that responded above. Forgot to fill in my name ....
 
9/10/2004 2:58 PM
Mark Hammer

To follow up on Mike's point, there is low and there is low. For instance, Gretsch pickups are lower impedance than PAFs, and have more sparkle to them. The lower impedance, is a result of fewer windings (and likely wire choice too).  
 
In contrast, the old Les Paul Recording guitars had these rather sizeable "low-impedance" pickups that had plenty of windings but a much thicker gauge of wire. These pickups had output impedances of much less than 1k because they were intended to plug into a recording console in exactly the same spot you'd plug in a voice mic.  
 
If you have an existing HB you don't mind taking risks with (or can purchase one cheaply 2nd hand), you can aim for what it is you want by removing turns from an HB with a "normal" impedance. For instance, if you carefully removed, say, 250 turns from the outside of each coil, you would likely reduce the measured DC resistance by 500-540ohms. So, an "8k" pickup would now be a 7.5k pickup, or a 7.6 would now be around 7.1k. To the best of my knowledge, this is likely the sort of lower impedance the Page guitar is using. Exactly how MUCH lower it is, I couldn't say, but I think it is safe to assume that it is unlikely to be in the range of a radical drop like 2k or more since that would result in serious disruption of pickup level matching.  
 
Although DC resistance is NOT identical to number of turns (especially in cheap pickups), it can serve as a reasonable proxy for number of turns. Consequently, while you are removing turns to change the tonal properties of the pickup, keep an eye on the DC resistance of the two coils. If you can match them a little better than they are presently matched, you can improve the hum-rejection in the process of modifying the tone.  
 
Finally, note that output level is a function of number of turns, so if you reduce the coil size to open up the top end, you will likely need to recalibrate pickup height so that the bridge and neck levels match (especially for N+B settings). It is very likely they will NOT match as well as before following the mod.
 
9/10/2004 10:14 PM
Jeremy F
Re:Gibson bobbin dementions?
Thanks. By the way, you wouldn't know where to find specs for a gibson humbucker bobbins, would you
 
9/11/2004 3:24 AM
Dave Stephens
From what I understood Page's Les Paul just has PAFs in it, I read the lowest wound ones were 7.5K, that really is not all that low, you will get plenty of kick and sparkle there. I have a "lite" set based on PAFs but using unequal coil winds for more frequency response and my bridge is around 6.8K and is very useable in my 335 Dot. The Gibson humbuckers that followed the PAFs were all wound to 7.5K I believe, and both coils matched very closely. These were called "T-Tops" because they have a sorta T mark on the bobbins. You can find these on Ebay for about $40-50 and they have plenty of bite and make good bridge pickups.  
 
 
 
Unwinding a humbucker is liable to be a major hassle especially if potted, and if you break the "start" of the coil you'll have to rewind the whole thing. Plus getting the tape off without breaking the coil wires is a tricky deal, you'd have to soak it in lighter fluid probably to get the tape off. I think a T top would be a good bet for you.....Dave
 
9/12/2004 5:01 PM
Jeremy F

According to the gibson custom page that talks about Jimmy's Les, both are based PAF pickups but the bridge is a lower output. Do you have the dementions of the bobbin that you could give me so i can make some bobbins. I need to know if they are 50 or 52mm or a completely different size. Thanks for the imput.  
 
Jeremy
 

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