Les Paul Lo-Z pickups

[paradoxjon]

thanks so much for the info....

My problem is not so much the low impedence output jack...

it's the high input one.

at the moment both of my outputs are exactly sounding the same..

really low volume, basically the guitar is unplayable, the 50-250-500 rotary switch is not working...

i have to get an engineer to restore the high output jack and the switch..

the problem is basically they don't really know how to go about with it...

so i'm trying to find as much info as possible for them..

[David Schwab]

the problem is basically they don't really know how to go about with it...

Do you have the schematic? Shouldn't be hard for an engineer to do when you have the schematic.

[clementc3]

The schematic should enable your tech to figure out what is going on with the internal transformer and/or rotary switch.

In the meantime, spring for a 1/4" jack to male XLR adapter and a Shure A95UF (which has female XLR adapter at one end and a 1/4" plug at the other end), to use the low-impedance output into a standard amp. You should be able to get both pieces for under $50 total. Connect the guitar to your normal cord, to the adapter, to the Shure A95UF, and finally to the amp.

The Shure A95UF info is here:

Shure - A95UF Line Matching Transformer (Female XLR to ¼? Male Plug/Female Jack)

[David Schwab]

Also, in the event that something is wrong with the switch or transformer, you can probably get a replacement part since Gibson has reissued the Signature bass as the Epiphone Jack Casady model.

But it probably needs to be rewired.

[mike.b.35]

Hi All, if a newb may be permitted to ask a dumb question or two ...

Recenty bought an LP Professsional which has been modified with an internal transformer for use with a standard guitar amp (i.e. is now locked to 'high' impedance output). The guitar is producing a decent clean tone and the decade control can be heard clearly, so assume whoever did the mod knew what they were doing.

However have tried the guitar through a couple of effects pedals with mixed results. In particular can only get a very limited effect out of an envelope filter and overdrive sounds very muddy (not that I was expecting much in the way of distortion given the reputation of the guitar). Assume it's all down to the pickups? Can anyone advise or comment please? Beautiful guitar but would like it to be a bit more versitile, esp want to use the envelope filter - perhaps an external pre-amp would help?


Many thanks

Mike

[David Schwab]

Hi All, if a newb may be permitted to ask a dumb question or two ...

Recenty bought an LP Professsional which has been modified with an internal transformer for use with a standard guitar amp (i.e. is now locked to 'high' impedance output). The guitar is producing a decent clean tone and the decade control can be heard clearly, so assume whoever did the mod knew what they were doing.

The decade control is a series of caps to roll off the high end, like that Stellartone ToneStyler.

The switch on the LP Signature is some taps on the transformer.

perhaps an external pre-amp would help?

I think that would solve your problem.

[clementc3]

Photo of a prototype low-impedance pickup

There is a Les Paul Recording Guitar on ebay now

Vintage collectable les paul recording - eBay (item 330440744242 end time Jun-13-10 17:14:59 PDT)

which reportedly was owned by Chuck Burge, and which has a photo of a prototype pickup. The ebay listing says "The pickups I'm including with this guitar (2), are functional and wound with a heavy gauge wire, coated in epoxy (they first did this on the Sunrise guitars) with a slot for replacing the bar magnet with ease." The photo is interesting, at least to me; too bad there aren't any other photos other than the head-on shot. No specs on the pickup are provided.

[David Schwab]

That's interesting. The "real" LP recording pickups were stacked humbuckers, but that looks like one half of it.

I picked up some bobbins from the LP pickups, so clearly this bobbinless pickup is a prototype or something. But the bobbins are about the same dimension.

The Triumph bass pickup doesn't have bobbins.

[clementc3]

Wire gauge reported in various low-impedance Les Paul pickups

This may be old news that is well-known to forum members:

"The Modern Era of the Les Paul Legacy, 1968 - 2008" by Robb Lawrence states that, "Two long Alnico V magnets were used ... one in each coil and both oriented with north on top. The lower coil was magnetically separated from the other by a Mumetal plate that serves as the magnetic load. Guitar pickups were wound with 24-gauge wire, while the larger bass coils were 32-gauge wire. Guitar coils were reverse wound to each otner and receive 300 turns from approximately 160 feet of wire. ... The output was [11.5-12.5] 4.7-5K D/C wire resistance with an impedance of 50 ohms. (They can vary by several ohms because the 24 gauge [32 gauge] wire varies in thickness and resistance per meter.)"

Later in the same book Bill Lawrence is quoted with respect to the Les Paul Signature pickup, "I used fewer low-impedance turns, what you call 42-gauge wire ... the normal humbucker with two bars in. ... I wound them to low impedance - on that pickup, about 2,200 ... due to the particular transformer, I had to change the number of turns instead of using it with a low-impedance amp."

[Grog3]

Hi, I realize that this is an old thread, I stumbled upon it yesterday. I have a collection of Gibson Low Impedance Les Pauls, Amp & spare pickups. I have several parts books & other odds & ends. There really isn't a huge interest in these unique guitars and pickups, but I've had fun collecting them for the last 20 years or so.

[bbsailor]

Hi, I realize that this is an old thread, I stumbled upon it yesterday. I have a collection of Gibson Low Impedance Les Pauls, Amp & spare pickups. I have several parts books & other odds & ends. There really isn't a huge interest in these unique guitars and pickups, but I've had fun collecting them for the last 20 years or so.

Georg3,

The reason why they are not or have not been popular is because the traditional electric guitar sound has been a high impedance pickup with a resonance in the 3 to 5 Khz range. The Les Paul low impedane pickups follow the input requirements of 150 to 300 ohm low impedance microphones direvtly feeding through an XLR 3-pin connector a signeal directly into a mic mixer of a Low to High Z mic matching transformer located at the input to the amlifier.

These low impedance circuits only needed a 2.5K ohm volume pot value and thus could use 2-conductor, shelded mic cable to make long runs wih no typical beyond 3 to 5Khz resonance losses with high-Z pickups. These low Z Les Pauls pickups had a relatively flat response out beyond 10Khz and had a different natural sound comapted to high Z pickups. The built in Les Paul Low Z tone had controls to cut both bass and treble and offers a variery of imposed resonances using a deade resonance shifter switch to attempt to mimic some traditional high impedance pickup sounds.

Guitars in the Les Paul low-Z pickup series had the matching transformer either built into the guitar or it was located at the amp end of a mic cable attached to the guitar. The decade switch always sounds better when using the remote mic stepup transformer as the 300 pf to 400 pf of high-z pickup cable capacitance (after the internal mic step up transformer) would get reflected back into the pickup circuitry through the 1 to 12 turns-ratio transformer and affect/minimize the range of internal sounds possible with on-board decade switch resonance selections. Les Paul liked to feed his guitar directly into the mic mixer inputs or any low Z microphone XLR inputs such as a remotely mounted mic matching transformer.

Joseph Rogowski

[clementc3]

Hi, I realize that this is an old thread, I stumbled upon it yesterday. I have a collection of Gibson Low Impedance Les Pauls, Amp & spare pickups. I have several parts books & other odds & ends. There really isn't a huge interest in these unique guitars and pickups, but I've had fun collecting them for the last 20 years or so.

That's a nice set you have there! The LP-1 and LP-2 look like they are in great shape, as do your guitars and bass.

These instruments don't get a lot of love; I can understand why the guitars don't work for many people but I think the low impedance basses (I have a Les Paul Bass and a Les Paul Triumph (and also some of the low impedance guitars)) have a fabulous tone, which I get compliments on.

Are you happy with the LP-1 and LP-2 tone?

[Grog3]

When I play guitar, I still prefer a high impedance Les Paul, but my main bass for many years was a Les Paul Triumph. I just recently started using a newer Thunderbird a bit more. I always wanted to meet Les at the Iridium before he passed, but I never made it. If he would have gave Gibson his pickup before guitarists like Eric Clapton overdrove high impedance pickups in a high gain tube amp, rock as we know it might have been much different. I still found them interesting enough to start collecting them. The guitars I seem to end up with, never really caught on, like the RD Artist guitar & bass. The LP-12 sounds pretty good, solid state electronics was quite new & expensive at the time that amp was sold. I believe it was around $1,100.00 in 1969, that was a lot of money at that time. You could gang up to ten LP-2's using one LP-1 preamp, very expensive & heavy It's a neat amp historically, but it may not make it out of my basemen any time soon!! Newer solid state amps in my opinion have a cleaner sound and make the low impedance pickup sound their best.

[David Schwab]

When I play guitar, I still prefer a high impedance Les Paul, but my main bass for many years was a Les Paul Triumph. I just recently started using a newer Thunderbird a bit more. I always wanted to meet Les at the Iridium before he passed, but I never made it.

Low Z seems to work better for bass because it's generally played with a more wide range hi-fi tone. I always wanted a Triumph. Now they are kind of expensive. I plan on making myself one… if I ever get around to it.

I wanted to get to see himat the Iridium too, and missed my chance. It's a shame too, since I'm so close to NYC. I did see him at a local music store once talking to the owner, but the staff told me not to bother him. That was back in the late 70s/early 80s.

If he would have gave Gibson his pickup before guitarists like Eric Clapton overdrove high impedance pickups in a high gain tube amp, rock as we know it might have been much different. I still found them interesting enough to start collecting them. The guitars I seem to end up with, never really caught on, like the RD Artist guitar & bass. The LP-12 sounds pretty good, solid state electronics was quite new & expensive at the time that amp was sold. I believe it was around $1,100.00 in 1969, that was a lot of money at that time. You could gang up to ten LP-2's using one LP-1 preamp, very expensive & heavy It's a neat amp historically, but it may not make it out of my basemen any time soon!! Newer solid state amps in my opinion have a cleaner sound and make the low impedance pickup sound their best.

Just in case you scanned this, and for others that scan things like this, please scan in grayscale, not as line art. So in other words, scan for a photo not for text, that way the images don't turn out as black blobs. You need to scan at least at 600 ppi for sharp text, and you might need to adjust the levels to get the background white and the text black, bt it would look so much better and preserve these ads for prosperity.

[David Schwab]

Hi, I realize that this is an old thread, I stumbled upon it yesterday. I have a collection of Gibson Low Impedance Les Pauls, Amp & spare pickups. I have several parts books & other odds & ends. There really isn't a huge interest in these unique guitars and pickups, but I've had fun collecting them for the last 20 years or so.

I was looking through your photos at Photobucket. That's quite a collection you have!