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His Royal Harness

This is 1959 harness. The bumblebees are the Mylar type. The black tubing was added except by the jack. Some harnesses have no insulation some do. It’s a crapshoot. These are Centralab pots-the date code is on the side on three of them. The fourth is also a Centralab but the code is on the top. Go figure.

OK, bad pun. Best I could do with the word harness. Electricity doesn’t know how old the parts are that it’s flowing through. If the values are the same, then the signal is the same. If the old parts have drifted, then the signal will change. I don’t usually measure the components in the harness when I get a guitar. If it sounds good and the pots work properly, I leave it alone. I have dropped new harnesses into a lot of guitars and I can’t say that a good new harness sounds any different than a good old one. Oddly (or, given the mindset of most of us vintage idiots, not so oddly) we will pay $1000 or more for a 58 or 59 date coded harness. I know, I’ve paid it. If you’re going to spend all that money to make your guitar right (or make your reissue closer to the real thing) you should know what’s in there.

There are four pots (you  knew that), two capacitors, a three way switch, a jack and a bunch of wire in a 335 or mono 355 harness. The pots in a 335/345/355 are 500K. There is a shielding can around three of them in a 345 and a stereo 355. The bridge pickup tone pot doesn’t get a can because it won’t fit (the pot is too close to the rim). So, don’t get your BVD’s in a bunch if your expensive 59 ES345 has only three cans. The capacitors have a value of .022uF. A 345 has the Varitone circuit-a two sided inductor (choke) and a 6 way switch with a load of resistors and capacitors (or two big multivalue chips). I’ve covered the Varitone in earlier posts so we’ll leave it alone.

Gibson used pots made by a few vendors and all the pots I’ve ever seen have a date code which is pretty useful if you don’t know what year your guitar was made. But keep in mind, a date code only shows you the oldest your guitar can be. You might find a 58 date code in a 60 guitar. You won’t find a 60 date code in a 58, however. Pot codes have 6 or 7 digits. Gibson generally used pots made by Centralab from 58 to 62. The three digit manufacturer code on a Centralab is 134. The next 3 or 4 digits are the week and the year. So a pot with the code 134832 would be the 32nd week of 1958. From 63 until 69 Gibson usually used pots made by CTS which have a 137 code. Same deal a pot with 137409 would be 9th week of 1964. Note that they added a second digit to the year in the 70’s to differentiate 60’s pots from 70’s and later. There were a few other manufacturers pots-mostly early on-that made their way into Gibsons. That’s another post.

The capacitors exert control over the tone pots. A higher number will be darker, a lower number will be brighter. The .022uF cap found in all ES non Varitone models is made by Sprague. The well known bumblebee (it has stripes, thus the name) cap was used from 1958 until around mid 1960. The Sprague “black beauty” (it’s, uh, black) was used from 1960 onward. I don’t know what they used in the 70’s. The very early ones (58 and early 59) are paper in oil type and the later ones are mylar. I don’t think it matters much except the paper in oil caps are supposedly more prone to drift. Any ES model with a shielding can used the same value cap but it was the disc type so it would fit inside the can. I’ve experimented with caps but since I usually have the tone control dimed, it doesn’t make any difference-the cap only affects the tone if the pot is backed off.

The three way switch was made by Switchcraft and is the long body type with a steel frame in a 335 and a brass frame in a 345 or 355. Brass is closer in color to gold, so that’s why they used the brass on guitars with gold hardware. The 1/4″ jack is also made by Switchcraft and is essentially the same today as it was in 1958. The wire is coaxial with a two strand braid on the outside and a cloth covered stranded wire on the inside. That about covers the “what”. The “why” is a longer story. Why 500K pots? I dunno. Why .022uF caps? Ask an electrical engineer.

Paper in oil bumblebees on the left. You can tell PIO from Mylar by the little filler at the top. The Sprague Black Beauties on the right are Mylar and don’t have the fillers.

4 Responses to “His Royal Harness”

  1. RAB says:

    Royal Harness, that’s a good one Charlie! You are the Royal Highness of thinline knowledge! Yes, the new, top quality harness you put into my ‘59 345 sounds great! And has the advantage of working perfectly too…no scratchy or noisy pots there!

  2. leedsy says:

    It would seem that Charlie is suggesting His Royal Harness needn’t cap his pot use, although resistance does not appear to be futile here. Perhaps Ohm meditation would be current. I’m done now.

  3. Rod says:

    What’s the consensus here? To my ears, for the same value, all capacitors sound the same, whether PIO, ceramic, whatever? Yet some people swear by POI (for example) and pay hugely for their (grossly overpriced) caps. To my mind, a decent tone pot with a smooth track is much more important. Although I will concede that SOME of the older pots seemed to have a smoother track. I still believe that capacitance is capacitance however it is achieved.

  4. okguitars says:

    I’ve always believed that values are values. Electrons don’t know old from new. There are folks who will dispute this but I generally believe my ears.

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