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Les Paul's Low Impedance "Staple Back" Pickups

Posted: Tue 09/12/23 11:22 am
by JMPGuitars
Yesterday I had the privilege to work on some of Les Paul's personal pickups and one of his guitars. The guitar is a ~1954 Les Paul Custom previously owned by Les Paul himself. One of his crazy Frankenstein LPs. The pickups were also his, but I don't know if they were previously installed in this guitar or not. I had to design and make a mounting plate to work with the pickups as to not alter the guitar (which is hilarious considering the crazy stuff LP did to his LP).

I tested the pickups with my Integrator (based on Ken Willmott's design), and made some comparison plots. The Integrator I had set to 0db assuming that would be better for the low as hell impedance / low output pickups. The pickups are nearly flat across the audible spectrum, and pretty closely matched. Both are done with heavier gauge wire using scatter winds. I had to repair/replace the leads coming from the pickups.

The following tests were done with my new leads connected:
Ls @ 1kHz, Rd @ 1kHz, Cp @ 100kHz, Q @ 3kHz, 10kHz

LP SB 1:
Ls 4.06mH
Rd 4.0926Ω
Cp Nope! (tried up to 200kHz, couldn't do it)
Q @ 3kHz: 12.94
Q @ 10kHz: 12.13

LP SB 2:
Ls 3.8mH
Rd 4.056Ω
Cp Nope! (tried up to 200kHz, couldn't do it)
Q @ 3kHz: 11.987
Q @ 10kHz: 12.26

Here are the bode plots:
LP Staple Back 1.jpg
LP Staple Back 2.jpg

Here's the guitar with the pickups on the plate I made, and a photo of the guitar complete with Les Paul's wacky pickguard:
les paul's les paul.jpg

The pickups are low impedance so I needed to make an adapter to use a low to high impedance adapter to use the guitar in a normal guitar amp:


Re: Les Paul's Low Impedance "Staple Back" Pickups

Posted: Tue 09/12/23 12:30 pm
by JMPGuitars
In a week or two I will be rewiring the electronics to be what Les Paul intended. Currently it's dumb, but I'll be making the electronics essentially match the LP Recording model setup, which will work great with those insanely low impedance pickups.

Now I need to find a transformer that would work well with it. The internet tells me it was a Shure A95U or A95UF, but I can't find those as standalone transformers. I may have to scavenge one out of one of those adapters.

I'm just guessing, but from what's in the electronics compartment, it could be an early prototype for what eventually became the LP electronics setup on the Recording and similar models. That's just me speculating though.