Les Paul Lo-Z pickups

[David Schwab]

Interesting topic. I have a Les Paul Professional and I have the Les Paul Bass pickups in my 1971 Jazz bass.

Come on, spill the beans! Seriously though, can you give us a DC resistance reading on the pickups? I have never read anything about them anywhere.

[J Martin]

I measure the DC resistance at 9.5 ohms. Fortunately I have a second LP Professional that is already disassembled waiting for restoration so I didn't have to take the player apart. I think that the pickups I made were even a little lower in resistance. I used side by side coils. I just made them using my intuition of what I thought low impedance electronics should be. I was inspired by Alembic at the time although I had never examined any of their pickups.

Generally you won't get enough magnet mass to be able to fit a low impedance pickup in a humbucker route. There is only one person I knew that made a workable LI pickup in the humbucker form factor and that was Tom Doyle from North Jersey. I believe he may actually have a patent on them. It was hush hush back in the 70's around his shop. His pickups, I believe, were higher impedance then the LP pickups because they were hotter and smaller, but still fell within low range. Its a compromise as usual.

[Rosewood]

9.5 ohms? Was that at the coil or the transformer? That sounds too low.

[J Martin]

The measurement was taken with the pickup loose on my bench. The Professional has no transformer, btw. Its only in the recording. Not too low, its in the speaker range. Don't expect a 1:1 transformer match. We are in the millivolt range.

#28 AWG is 66.11 ohms/ 1000ft. #30 AWG is 105 ohms/1000 ft., # 32 AWG is 167.2 ohms/1000 ft, at 68 degrees F.

[Rosewood]

With that kind of low-Z what preamp or amp do you use? Or were they intended for direct recording?

[J Martin]

Sorry I wasn't clear about the transformer. The LP recording has an internal transformer. The LP Pro has an inline, mic type transformer. It works with any regular guitar amp. You can use a 200 ft. guitar cord with the transformer at the amp end, if you want. Very low losses.

[Louie Seven]

~~~~~~this is good!~~~~~~~~

[Rosewood]

I'll have to say that's the lowest low-Z I've ever seen. Anyone else making low-z pickups that low? I would think anything below 1k would be considered low-z.

[tbryanh]

I measure the DC resistance at 9.5 ohms.

I was wondering if you didn't mind measuring the resistance of the other pickup just to verify this doesn't have shorted turns.

Thanks

[Louie Seven]

Well....... in a twisted turn of luck, I surfed into a German site about THE LES PAUL RECORDING GUITAR. A translated version of one paragraph follows (it's possible that the non-translated original text is more decypherable *haha*:

For electronics Freaks: The Pickups has a resistance of only 10.8 ohms - round a thousandth of what one knows otherwise in such a way. Their inductance - the actually crucial size - is 8 mH. The frequency response is ruler straight and is enough until far over 200 kHz. This concerns “coaxial” Humbucker so mentioned, i.e. with two coils, which sit one above the other. Like that the decrease is limited to a very short piece of the string, so that one kriegt hard heights as with a normal single Coil Pickup; but nevertheless it does not hum, if one comes the amplifier too close. The Pickups is filled and practically indestructible with epoxy resin. They do not hang on three screws and wackeln thereby.

So........ that's interesting. I'll let the engineers here sort it all out, technically I mean. I guess no one will ever know what kind of slugs are in those things without cutting one open or Xrays. As regards these options ...the former is draconian, the later is expensive.

ANYWAY....... here's a link. http://translate.google.com/translat...l%3Den%26lr%3D

[David Schwab]

Wow, much lower than I expected!

my pickups are practically high impedance by comparison!

I guess it makes sense, if a 8K pickup has a 250K or 500K pot, a 10 ohm pickup would have a 1K pot.

[Mark Hammer]

The coil is really only a small part of the recipe. The magnets in those things were clearly VERY different from what we're used to around here. Unfortunately, with the pickup seemingly epoxied it was hard to tell what the magnet form/type might have been. All I know is that that sucker was heavy and the magnet much stronger than any single coil I've ever come across.

[David Schwab]

I seem to remember reading they were cobalt steel magnets, like the kind they used in the original CC pickup. Big ass magnets.

I doubt you need one of those though, unless you just want to replicate the pickup. having a metal core helps to bring up the inductance, which will give you more output. You don't have the usual problems with inductance messing the highs up because the coil is so low resistance.

[Louie Seven]

Wow, much lower than I expected!

my pickups are practically high impedance by comparison!

I guess it makes sense, if a 8K pickup has a 250K or 500K pot, a 10 ohm pickup would have a 1K pot.

The Gibson circuit diagram indicates 25K pots...for whatever that's worth.


Louie

[David Schwab]

The Gibson circuit diagram indicates 25K pots...for whatever that's worth.

Not on the schematic I have. I have one for the Triumph bass, but that doesn't list values. That's an actual Gibson schematic. The one for the recording guitar is hand drawn, and list the values. I meant to say 2.5K also.

I got these back in the 70's from a Gibson repair center. They are photocopies, and I colored in some wires and marked the controls in red to make it easier to read.