1950s/1960s Gibson Electricals

Catalog of Electrical Components As Used By Gibson in the 1950s and 1960s

(All page setup, and text Copyright © by Rick Norman, March, 2023 - All photos by Rick Norman, except where noted.)
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This page shows some of the various interesting things about the major pieces and wiring execution of the Gibson wiring harnesses of the 1950s and into the 1960s.
For many years I have been renewing and reconditioning these great old vintage wiring harnesses. I've done this for well-known vintage parts dealers, individual owners, and for my own instruments. Doing this work has seen hundreds of old Centralab and IRC pots, Grey Tiger and Sprague caps, and Switchcraft switches galore pass through my hands. I've also repaired a ton of vintage Gibson (and Fender, to be truthful) pickups, but those pictures and tales will be the subject of another page.
I have also had my hands, tools (and camera lens) inside more old Gibson electric guitars than I could possibly count - definitely considerably more than I could have predicted when I first started doing this simply for my own instruments. I've had the good fortune of seeing enough to have a good eye for when something is different or unusual, or... wrong. I've attempted to capture some of the interesting variances of these parts and wiring.
This page is a living document. I will be adding pictures and information as I learn it. Check back often!

Switchcraft 3-way Toggle Switches
While the function of the Switchcraft 3-way switches didn't change (except for the three-pickup Les Paul Customs of the late 1950s), certain details changed between the 50s and the later versions. Here are some pictures to show some of the differences.
The switches used through most of the 1950s had no lettering on them that identified them as Switchcraft brand switches. That changed in the very-late 1950s (as best I can tell), if not into 1960.

But what if the switch is still installed in the guitar? How can you tell if the switch is a proper 50s switch? There are a couple of quick 'tells' that identify the 50s-generation switches from the back. One of the differences is the order that the electrical 'leaves' are assembled, and another is the direction the stack screws pass through the stack. Here's a picture of the early-style switch to show what a proper 50s switch looks like from the back:

Now compare that one to the later/current-style switch:

An interesting thing that varied with no real pattern is how they accomplished the 'both pickups on' function of the middle switch position. There's a simple way, and a complicated way, and they both produced the same result with the same switch.
The simple way was to join the two upper terminals together and connect the lead to the output jack to that junction. That method did get used back as far as the earliest Les Pauls (I've handled an 'orange wire' '52 harness that was wired that way), and appeared throughout the 1950s. But despite its simplicity, it wasn't the only method found in the 1950s.
The more complicated method was to run the pickup leads to different terminals than you see in the 'simple method' and then run an extra piece of wire across the back of the switch in the form of a jumper to accomplish the 'both pickups on' function in the middle switch position. This was used at least as often in the 1950s as the 'simple' method.
Why were two different methods used? There's no way to know for sure. I personally believe that the wiring method varied with whomever was assigned to the soldering station at the Gibson plant on any given day. Just my opinion, of course. Here's a picture showing both ways:

This illustration shows how the two different wiring schemes actually hook up to the switch.

This picture below shows the central ground for the entire electrical circuit in a Les Paul, ES, and probably any other Gibson multi-pickup electric from that era.
The pickup(s) grounds to its respective volume control through the braided shield on its lead.
Then, the volume controls ground through the braid shield on each lead going to the selector switch, which, through the connection shown in the picture below, grounds to the final lead running to the output jack, completing the ground plane for the entire guitar.
All that leaves is grounding the tone control pots. In a Les Paul, the nearest connection to the ground plane is through one or both volume pots.
Various schemes were used to connect the tone control to its mating volume control. But that's not the point of this picture...

This picture shows how the common lead from the selector switch connects to the output jack.

IRC Pots
IRC pots were the ones used in the earliest Les Pauls. Starting in the approximately 1953, Gibson started using Centralab pots concurrently with the IRC pots.
The latest IRC pots I've seen in Gibson use was up to very-late 1955. In a couple of cases, I've had a wiring harness that used both brands simultaneously. For example, I once had a completely-original very-early 1956 Les Paul Junior harness that had a very-late 1955 IRC volume pot and a very-early 1956 Centralab tone pot, with a Grey Tiger tone cap. (If anyone has evidence of later IRC pots, please forward that information to me!)
IRC pots changed little during their use in the 1950s. The major notable changes were to migrate from a solid shaft to a split shaft (as did the Centralabs), and a slight change to some of the coding stamped into the back cover. The following pictures will show some of the variations.

This picture shows the overlap of the two brands as late as 1955

Centralab Pots
As early as 1953, Gibson started using Centralab pots concurrently with IRC pots.
As with many of the hard-parts that Gibson used in the '50s, features of the Centralab pots changed over the years. The following pictures will show some of the variations.

Braided-shield Connecting Wire - Vintage v. Modern
This is another 'some know this, some don't' thing, and doesn't require much explanation because a picture tells the story. I don't know exactly when Gibson stopped using the 2-strand-weave shielded wire, but it had to be into the 1960s, and maybe even later.
This happens to be one the few things in the Gibson guitar electrical chain that literally makes no difference in tone (along with the selector switch and the output jack). I believe the change occurred outside of Gibson's hands, meaning perhaps their wire vendor changed its manufacturing practice and that was that. Or they just changed vendors outright, possibly because they got a better deal from someone else. Since it literally makes no difference, there was no reason not to go with the best price. We could guess all day, couldn't we?

Tone Capacitors Over The Years
This section will eventually show the various tone caps that Gibson used over the '50s and into the '60s, some more commonly than others. I can't say this list is complete, because as time goes on and I have more instruments (or pictures taken by others) across my bench, I still see something new. Capacitors (and how they were installed) varied the most of all the electrical components in the 1950s.

'Chicago' Capacitors
This picture shows a very early (trapeze-era) Les Paul (note the routed channel for the string ground and the IRC pots). This is the one-and-only time I've seen this brand of capacitors in a Les Paul, but... I also don't doubt that there are others from this specific batch of guitars that received them. Interesting tid-bit, eh? If anyone else has good pictures of these caps in other Gibson instruments, Les Pauls in particular, I'd love to see them!

'Grey Tiger' Capacitors
Grey Tiger caps were the most common caps for Les Pauls (and other Gibsons) during the early-to-middle 1950s. They came with both red and black inked-lettering.

'Sprague Black Beauty' Capacitors
Sprague capacitors started appearing in roughly 1956-ish. The first model to get used were the 'Black Beauty' model, though they are most commonly called 'Bumble Bees' or just 'Bees'. That isn't Sprague's name - Sprague's official name actually WAS 'Black Beauty'. 'Bumble Bee' or 'Bee' is aftermarket slang. It's not hard to see where the nickname came from though.
The first version of the Black Beauty model to be used by Gibson was of 'paper-in-oil' (PIO) construction, which was very common across many other capacitor manufacturers in those days. Look at the picture below. It shows how to identify a PIO version of the Black Beauty.

Using Old PIO 'Bees' in Modern Guitars
Tons of people LOVE to hunt down old PIO 'Bees' to install in their modern Les Pauls and such. Personally, I'm not a fan of that. Part of the reason that the industry in general moved away from PIO construction is that they're not stable over time, don't respond well to being heated, etc.
More directly, it's 'iffy' whether an old 'Bee' is still actually the value that its labeling says it is. Over the course of my years of reconditioning old Gibson harnesses, using a good quality dedicated capacitance meter, I've measured every single capacitor in every single harness sent my way, not even counting the loose 'Bees' sent my way. I can say with absolute authority that a full 30% of them have drifted upward in value. I've had .022uf PIO 'Bees' measure as high as .035uf.
I'm not saying you shouldn't use old PIO 'Bees' in a modern guitar, or in your vintage restoration, etc. I'm suggesting that you hunt down caps that have been tested. I personally would be very wary of any old PIO cap that was known to have come out of an old TV set, hi-fi set, public address amplifier, etc. - anything that operated at high voltage. I just don't advocate having old PIO 'Bees' in any modern guitar just for the sake of it... when there's a measurable chance that it will actually hurt your tone. I'm suggesting that, for modern guitars, it's better to have modern, in-spec capacitors in your guitar than old-but-out-of-spec 'Bees' just for the sake of bragging rights. I'm also suggesting that if you're restoring an old Gibson that would originally have had 'Bees', keep searching for a pair that can be proved to still be of the rated value.
I'll get off my soap box now... LOL

Second Version of the Black Beauty
The second version of the Black Beauty model was of mylar construction as Sprague and a whole lot of the capacitor industry moved away from PIO construction. Initially the mylar Black Beauty caps continued to use color-coded stripes to indicate their value. From my memory, these started appearing in Gibson guitars in late-late 1959, and I've seen enough to know that there was some overlap with the PIO Black Beauties. If anyone has good pictures showing mylar Black Beauties earlier than that, please send them along so I can update this information. Look at the picture below. It shows how to identify a mylar version of the Black Beauty.

Final Version of the Black Beauty
The last version of the Black Beauty model was still of mylar construction. The only change was that Sprague moved to inking the specs on in letters and numbers instead of painting on colored stripes. Again, in my experience, these started appearing in Gibson guitars in 1960-ish. The two pictures below show what the last version used by Gibson looked like.

'Sprague Phonebook' Capacitors
I don't know what Sprague's designation for these caps was, but they're most commonly referred to as 'phonebook' caps, so I'm parroting it for you. The only places I've seen them is in some Les Paul Customs and in some ES3x5 guitars in the late 1950s and very-early 1960s. If anyone has pictures of Gibsons with these from earlier dates, please send them along.

'Astron' Capacitors
For the sake of interest, Tom Wittrock sent along this picture of a 1960 burst with Astron brand caps. I have NO idea how much this brand got used, but here it is!

Very recently (January 2023) I received this photo of a 1960 Junior with an Astron cap from Jim at Admiral-Music in Kansas City, Kansas. This proves what common sense suggests - for a brief period, Gibson had a batch of Astron caps and used them across model lines. Thanks to Jim for graciously allowing me to add this picture to this page.

And finally...
Ceramic Disc Capacitors
There's not a lot to be said. EVERYONE has seen these... for years and years and years. The picture below is of a super-early Les Paul/SG. They've remained the 'mainstream', go-to cap for decades, and not just for Gibson. Nuff said about these.

Ground Those Tone Pots!
This section shows the various methods Gibson used to connect the tone pots to the ground plane. For now, the pictures in this section will only show regular Les Paul models over the 50s. Mostly because I simply don't have enough good photo evidence of ES style guitars, as well as Les Paul Specials. I'll add that as I acquire good pictures.
What I will say is that instruments like ES models and Juniors kept it simple. A Junior, for example, simply soldered the braided shield of the output lead going to the output jack directly to the casing of the tone pot as the lead was passing by. Similarly, the routing of the leads to the volume and tone pots in ES guitars was such that they also used the braided shield of nearby leads to complete the grounding of the tone pots.
Les Pauls and Les Paul Specials and SGs and such had to make do with different schemes.

Early 50s Les Pauls
The early 50s Les Pauls had a ground scheme that connected the neck pickup volume pot (which is connected to the ground plane through the braided shield on the lead from the volume pot to the selector switch) to the neck pickup tone pot, and to the bridge pickup tone pot. In these schemes, the bridge pickup volume control has no ground connection to the bridge tone pot.
Look at the two pictures below - the upper picture is the early-early '52 seen in pictures in other sections. The lower picture is of a '54. Clearly, the order in which the pots are grounded is not important. Also note that in the early days, the ground buss wires had insulation sleeving installed. This didn't go on forever.

Middle-50s (and later) Les Pauls
Starting in the middle 1950s the tone pot grounding scheme evolved to the configurations we're most familiar with.
There were two basic configurations. What they had in common is that they got the bridge pickup volume pot into the game. Now the bridge pickup volume and tone pots got connected, and similar for the neck pickup controls.
The variation is that sometimes one piece of buss wire got wrapped around to connect all four pots. I call this scheme a 'horseshoe ground'. In the pictures below you see the most common layouts we've all seen before.

The important thing to know about this is that there is no benefit to one or the other. In fact, the extra length of wire connecting the two tone pots is literally unnecessary. Remember, the central ground for the entire harness is up next to the selector switch. So if you're planning to wire up your modern Les Paul to 'look vintage', you can select either method and still be 'vintage-accurate'.
Other things to note about the ground buss of this era are that the ground buss is no longer insulated. Also the gauge of the ground buss wire was not consistent. Take a look at the pictures of the '52/'53-era controls - underneath the insulation sleeving is smaller buss wire than what came later. Take a look at the picture of the 'Astron' capacitors in the section on capacitors - the gauge of the ground buss wire is smaller. I've seen this subject (gauge of ground buss wire) debated and fretted over... IT MAKES NO DIFFERENCE. It's the GROUND PLANE, my friends. LOL. It does not effect tone. It does not impact shielding. There was not just one special gauge of wire used. Nuff said. LOL
In the pictures below we get to see examples of where an extra-long stretch of string ground wire is used to implement the pot grounding scheme.
The first picture shows a very-early wrap-tail guitar. Notice the unused trapeze string ground channel as Gibson was using up the existing stock of trapeze-era mahogany body backs.
This second picture looks to be a late-'55 or early-'56 Goldtop.

String Ground Methods Over The Years
This section shows the various methods Gibson used over the '50s to accomplish the string ground. As the Les Paul line moved along from its original trapeze bridge to the stop-tail-only to the ABR/stop-tail and ABR/tremolo, different methods were required. Again, most people know all this, so this section is more for those who don't.

'Trapeze-era' String Grounds
We all know that the very-earliest Les Pauls had a trapeze-style bridge, much like the archtop hollowbody guitars in Gibson's line. As such, the supports for the trapeze cross bar rested on round 'feet', not a bushing or stud sunken into the body. Similar to the archtops of the day, the string ground was accomplished by running a wire back to the butt end of the guitar, through a hole (often the hole drilled for the strap button), and then the anchor for the trapeze legs was screwed down to the end of the guitar, making sure that the protruding wire was in contact. The other end of the wire was soldered to the casing of the potentiometer most easy to reach.
Fairly easy to do on a hollowbody, yes? How did Gibson do it on its first solidbody? Look at the pictures below. In addition the various channels routed into the mahogany body back for the selector switch and pickup leads, a channel was also routed that went between control cavity and the butt of the guitar.

'Wrap-tail-era' String Grounds
With the introduction of the original stud-mounted wrap-tail, a different scheme was possible for the string ground, and the extra channel routed into the body (shown above) was no longer required.
The new method was to drill a hole between the pickup cavity route and the nearest tail piece stud hole. A thin wire was run through the drilled hole from the pickup cavity into the empty High-E stud bushing hole, and then the stud bushing was pressed in. The other end of the wire was then soldered to the nearest available location in the overall ground plane.
Two different methods were used to connect to the ground plane. One, as shown below, was to simply wrap the string ground wire around the braided shield of the pickup lead and solder.

The other method was to run the ground wire all the way through the diagonal wire channel, into the control cavity, and then solder to the neck pickup volume pot casing.

Why was one used versus another on any given guitar? My best guess is that, like my guess regarding the wiring of the selector switch, it was a personal preference thang for the person who happened to be assigned to the soldering station on any given day. And I'll say again... that's just a guess. There's no real electrical reason to favor one method over the other.
Just for the sake of visuals, here's a picture of a 1957 Les Paul Junior pickup cavity. What there is to see here is a demonstration that one-piece guitar bodies (Les Paul Juniors, Les Paul Specials, and the original 1950s Les Paul Customs) couldn't take advantage of a routed channel for all the leads. For these guitars, all access to the control cavity was via drilled holes.
On a Junior, with only one lead needing to pass between the pickup cavity and the control cavity, the drilled hole was quite small, yet Gibson still ran the string ground down through the tiny hole and soldered it to the volume pot (at least on this particular guitar). Due to the shallowness of the pickup cavity perhaps the assembly person felt there simply isn't enough room to leave a string ground with enough length to comfortably wrap around the pickup lead.

I haven't seen inside nearly as many Juniors as I'd like, so if anyone has pictures of other implementations on Juniors, please send them along.
Likewise, I've only seen the insides of a few Les Paul Specials of that era so I'd like to get some good, detailed pictures of the guts of both single-cut and double-cut Les Paul Specials.

'ABR-era' String Grounds
The introduction of the ABR bridge moved stud-mounted wrap-tail back on the body and given a demotion in responsibility. (Kidding...)
The displacement of the tail piece placed it in excellent proximity to the control cavity. It was now possible to drill a hole from the High-E-side tail piece stud bushing hole directly into the control cavity, emerging right next to the neck pickup volume control pot. This is the look most of us are most familiar with.

'ABR with Tremolo' String Grounds
Hmm... that last solution sure works... unless you ordered your Les Paul (or ES) with a Bigsby (or other) hand tremolo. If the order for the guitar reached Gibson in time, the guitar never got drilled for stop tail studs. And even if your guitar did happen to get built with stop tail stud locations, the strings never touch them. Something else needs to happen, yes?
Is a new solution required? No, an old one! Meaning, drilling a hole from the bridge pickup cavity to the High-E ABR stud hole, similar to the wrap-tail guitars
This picture shows a 1958 Les Paul, and on this particular guitar, the assembler soldered the free end of the string ground around the bridge pickup lead as shown. Like wrap-tail guitars, the string ground could just as easily been run down the wire channel and soldered to the back of one of the pots.

The 'Modern Wiring' Ain't Really So Modern...
'50s wiring' or 'modern wiring' - which is better? Which should I use? Boy, has that been debated! Not that this alters the quality of anyone's day, but... what has become known as 'modern wiring' isn't really all that 'modern'. It was used in the late-1950s by Gibson, and probably earlier if we could find pictures to prove it, and who knows how many other instrument companies wired their instruments in the manner many folks call 'modern', and for how long.
I'm only going to show pictures of one guitar's guts, but believe me, it's 100% factory-original, and it's not a one-off. I've seen this configuration in multiple complete Gibson guitars of the late 1950s, and more examples among the 1950s Gibson harnesses I've received out of the guitar to refurbish.
The pictures below are of a 1958 Les Paul that spent some quality time at my house. Its controls are entirely original.
Oh, by the way, also notice that the capacitor lead connected to the tone pot is connected to the center terminal (wiper), and the outboard terminal is grounded, versus the other way around seen more commonly. Electrically, that particular wiring choice literally makes no difference.
Again, not earth-moving info, just a little evidence of why I snicker at the term 'modern wiring'.