Tone and Treble Bleed mods

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This setup should be standard - allows one to remove most of the electronics easily. All my other guitars have everything hidden beneath a big pick guard, under the strings. Maybe a Les Paul is required here, then I can get to the back of the pots.

This guitar allows me to play around with tone capacitors and treble bleeds without having to remove strings, fifteen screws, unsoldering the output jack, and such fun. In and out in minutes.

Here is the inside of the "module". That coloured capacitor was the tone capacitor. It shows the guitar's age, and resulted in much googling to find the value as .047 microFarad. To my surprise, the log taper potentiometers are 100K. Would the "standard" 500K make any difference? And the two potentiometers are not the same number, both 100K LOG, but different numbers.

I spent hours salvaging capacitors and resistors from old junk, before finally junking it. I replaced the tone capacitor with this .015 microFarad (? It does not follow the numbering system of 153, and is too large to be picoFarad?) Guitar is much brighter now.

The treble bleed circuit is the "Kinman" style, a 2 nanoFarad capacitor with a 22 K resistor. I find the "Fender" style to have better volume spread at low settings, and cannot really say which style has the better volume taper. I have tried a 1 nanoFarad capacitor with a 100K resistor in series as here, as well as those in parallel, with a 10K resistor in series to that. If I had a bigger variety of components, I could play around some more, to fine-tune values and setup. At least this gives me a rough idea of what happens. Now, to upgrade to one volume pot, two tone pots. But, the CTS style pots have a bigger diameter, and might not fit in quite so easily.

Your input as to whether 500K pots will be better, and favoured tone capacitor and treble bleed style and component values for humbuckers please?

V8

Since these were for both bass and guitar, I guess they didn't bother with marking the pickups with a value. If I were to guess, the one's on my old bass were 10k+, fairly hot for the time. They are great pickups.

I expect the guitar would get brighter as you upped the values of the pots. Maybe start at 250 and see how bright you want it?

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I have on hand this handy item too: Bought back then, almost never used, due to the three way switch being broken (as bought or just shortly afterwards? Cannot remember) and if I did use it a few times, it would have been with only one pickup going through. I looked at it, there are enough tabs on the switch to allow me to jump/re-locate wires, losing the "stereo" output. I am not planning on using it anyway.

From what I understand (from wiring diagrams on the net), the rhythm/solo switch bypasses the tone pots in "solo", giving the amp all you can. Which is not much with 100 K log volume pots.

I measured the humbuckers' DC resistance. They are coil-tapped, but on these two modules, used as a full humbucker only. But, the possibility for splitting them various ways exist, not that I am up to sorting out that wiring jumble soon. Five way switch?

If I am correct, the pickups measure:

Neck: 6.1 K and 6.2 K, total 12.3 K?
Bridge: 3.97 K and 4.4 K , total 8.4 K?

Not quite low values, although they sound like it. Time to swop out the potentiometers for 250 K or 500 K and more signal to the amplifier. If that theory holds up, I have been playing at 1/4 volume and less all these years.

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I at long last ordered some 500K Log pots, maybe CTS, but the number on the pots does not show on their site, and googling does not find the pot number. I did check with the multimeter, roughly, they are Log, maybe 10% Audio, but ideally I need to mount one to a backing plate, draw out positions accurately, and then measure the taper. What bugs me, is that the normal pin-outs (left = in, centre = out/wipre, right = ground) as viewed from bottom side, does not make sense in terms of resistance compared to CTS diagrams. Never mind, wired up with clockwise = full volume, counter clockwise less volume. The last bit of the travel to maximum volume is rather drastic in volume response. Should work for players who need fast volume "swells". Could be handy when doing a quick solo in a song. Or driving the amp from "music" to "noise".

It being late at night, and feeling brave (with no liquid anti-stressant within reach), I removed the old, small 100K pots. The Tone pot fits with no hassles, but I had to "slot" the hole for the larger diameter Volume pot, to allow clearance from the plug and wires. Not what I like to do, but no options here. I wired up everything as standard, but with a new 0.01microFarad tone capacitor. Sounds did emanate from the amp. But the tone control was kind of, well, weak. Bright sounds went to slightly less bright sounds. Not enough.

Before starting to fit a bigger capacitor the next morning, I verified that the wiring is as internet sources for Tone Pots show. It is not, refer to the diagrams in the previous posts. I re-wired it to the "conventional" (?) layout, with the input from Volume pot on wiper (lug "2"), capacitor on lug "3" (bottom view), connected to ground, lug "1" open. I had good control now.

Confidence at a high (and thinking ahead to a celebratory drink..), I made up a new Treble Bleed thingie, using the "Kinman" layout, with a 120K 1/4 Watt resistor and 0.001 microFarad capacitor. (The values he lists are not standard values.) Works OK. I shall play for a while to hear if I like it in the longer term - I have some picoFarad range capacitors if required, but, still, no stash of resistors to play around with. Ideally I should find said stash, and compare all the styles of treble bleed wiring.

The picture shows it all. I leave the leads long on purpose, I would like to be able to re-use the components in future, if needed, and cutting the legs too short sort of makes that a remote possibility. Ah, caught out? No, the 1/4 Watt treble bleed resistor is in that long black heat shrink sleeve. Apologies for the koki-pen on the Tone pot, that was the marks I put there when I first measured the taper and decided where what goes. I was wrong, and I re-marked. You are, of course, correct: I should clean it off.

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I have not played this guitar that much over the last year, other projects filling up the time. I do find the pickups to be clearer, and the tone is now very (very) bright, I would say paper thin glass brittle bright. But not a single coil sound. Turning tone pots only helps that much, but the Laney Cub 10 amp does make it tolerable. So, yes, 500 Kohm pots were too much.

That other module was stripped down to the bare plastic plate and re-built using a new three-way switch. The plan was to copy this Module 1’s original setup, but the original 0.047 microFarad tone capacitors all have one broken-off leg now. Two of the pots also decided to lose a tab, fortunately I had six to start with. I changed the tone pot capacitor to a 0.015 microFarad, wired up as per Seymour Duncan two humbucker/one volume/one tone diagram. The idea is to hear how much the 100 Kohm volume pot darkens the tone, the tone control frequency response itself is not important right now.

Several hours of sukkel and swearing did eventually end up with a functional unit, the “stereo” output wiring now altered to mono. (The related “Fixing a broken three way” post describes the fun I had with the original output wiring.) The new (“DiMArzio TM”) three way switch seems to be too tall to fit the cavity, and the tone pot is wired wrong way round, and it seems as if the wiring colour codes are wrong as well, confirming a note on that subject, a long time ago.

The 100Kohm pots makes direct comparison difficult, but I will confirm that the excess brightness is diminished with the 100 Kohm pots. I shall look into new pots for the Module 1 when I have the courage to work on this again. Meanwhile, I can try to source 470 Kohm to 150 Kohm resistors to parallel up with the pots to “make” 250 Kohm and smaller pots, should be realtively easy to compare tone that way.