A better treble bleed circuit

[asdaven]

Feb 8, 2023 22:18:24 GMT -5 JohnH said:

What I posted above is where I got to, for the best TB recipe, though there is room to adjust values for personal taste.
The main story leading to this is on pages 1 and 2 of this thread

So im thinking about using a 680PF cap since I want less treble bleed effect. So I should still stick with 150K and 120K resistor values with the smaller cap? Alot of treble bleed recipies with a smaller use a larger resistor. I understand a smaller cap passes less frequencies. Just trying to understand what lowering and raising the resistance values in a parallel treble bleed does?

Thanks-

[asdaven]

So I tried a 680pf capacitor with 150K resistor in one of my guitars with 500K pots and it dosent sound thin and does sound good to me.

The problem is in some of my guitars, I use vintage audio taper pots for the volumes, which I was doing with standard wiring to slow down the roll off. They are 30% audio taper. A couple of them have standard 10% audio taper for the volume. All tone pots are standard 10% audio taper.

That being said, with the one guitar and the 30% audio taper pot, the 680pf/150K combo reduced the taper to Linear and then some. I wanted a slower taper but this is too much. Theres very little change in volume then all the way off at the very end.

I know somebody was mentioning they were using a linear taper volume pot earlier in the thread. But what about the 30% audio taper pots? Would adjusting the resistor value adjust for the more gradual taper of the vintage taper pot?

[reTrEaD]

Feb 20, 2023 14:48:55 GMT -5 asdaven said:

Just trying to understand what lowering and raising the resistance values in a parallel treble bleed does?

The capacitor in the treble-bleed has more effect, the more further the volume control is rotated counter-clockwise. The lower the value of the resistor, the more it mitigates the over-compensation at lower volume levels.

Feb 21, 2023 19:39:47 GMT -5 asdaven said:

So I tried a 680pf capacitor with 150K resistor in one of my guitars with 500K pots and it dosent sound thin and does sound good to me.

The problem is in some of my guitars, I use vintage audio taper pots for the volumes, which I was doing with standard wiring to slow down the roll off. They are 30% audio taper. A couple of them have standard 10% audio taper for the volume. All tone pots are standard 10% audio taper.

That being said, with the one guitar and the 30% audio taper pot, the 680pf/150K combo reduced the taper to Linear and then some. I wanted a slower taper but this is too much. Theres very little change in volume then all the way off at the very end.

I know somebody was mentioning they were using a linear taper volume pot earlier in the thread. But what about the 30% audio taper pots? Would adjusting the resistor value adjust for the more gradual taper of the vintage taper pot?

The resistor in the treble-bleed affects the law of the pot, slowing down the reduction of volume during the first part of the rotation away from full clockwise. If a 30% (J-taper) pot is too slow for your tastes at the clockwise end of the rotation with a treble-bleed, you may prefer a 25% (H-taper), 20% (BD-taper), or 15% (B-taper).

[asdaven]

The taper was fine before I added the treble bleed circuit. Now its really a linear taper. Just want to tweak it to alter the taper less. I see other treble bleed circuits that use lower value caps using higher resistance values. Im thinking I just need to up the resistor value here to compensate. I think John suggested maybe 280K resistor for someone earlier in the thread who was trying to use a linear pot. I wonder if going with a 220K resistor would work better with the J taper pot?

[reTrEaD]

Feb 22, 2023 7:44:07 GMT -5 asdaven said:

I wonder if going with a 220K resistor would work better with the J taper pot?

I suppose that all depends on what you consider "better" and what your current results are in mitigating the inherent over-compensation of the treble-bleed capacitor at substantially reduced volume settings. A larger resistor will have less effect on the law of the pot but will also provide less mitigation. If you currently experience some treble loss at substantially reduced volume setting, increasing the value of the resistor is definitely the way to go. If you're happy with the amount of treble content at substantially reduced volume levels, then changing the pot for one with a faster taper at the CW end (lower % value at midpoint) would be the preferred path.

[JohnH]

You could try a 220k with the 680pF that you have, given its with a smaller cap, you might like it but it's up to your ears to decide.

[asdaven]

Feb 22, 2023 15:11:06 GMT -5 JohnH said:

You could try a 220k with the 680pF that you have, given its with a smaller cap, you might like it but it's up to your ears to decide.

If I like that value for a 500K J taper volume pot, how would I adjust for a 250K J Taper volume pot in my other guitars?

[JohnH]

......try different values until you like the result. With a 250k pot, maybe 680pF and say 180k?

[asdaven]

Feb 23, 2023 7:26:38 GMT -5 JohnH said:

......try different values until you like the result. With a 250k pot, maybe 680pF and say 180k?

Thats what I figured. Unfortunately I changed many of my guitars to these vintage taper pots because I gave up on treble bleeds awhile back. The slower taper is kindve a treble bleed in a way because it dosent turn down and get as dark as fast. Kinman got the best result but in my Strat was way too bright. But on your graph, the Kinman behaives in a weird way.

But I love the effect the 50s wiring has but I cant live with the tone pot turning down the volume. But with the tone dimed on 10, I really liked the volume roll off. Im just trying replicate the roll off with 50s wiring with a treble bleed as close as possible.

So far, I like the smaller cap. I do want some darkening of the tone as I roll off but I just dont want it to turn down to mud and a not-useful sound. Others who are fans of treble bleeds... want to maintain full treble all the way down. Im not in that camp. I want it to darken some rolling off. Just going for anti-muddiness more so than a treble boost.

[Yogi B]

Feb 23, 2023 10:50:29 GMT -5 asdaven said:

But I love the effect the 50s wiring has but I cant live with the tone pot turning down the volume. But with the tone dimed on 10, I really liked the volume roll off. I'm just trying replicate the roll off with 50s wiring with a treble bleed as close as possible.

Does the solution need to be a treble bleed?

The trouble with treble bleeds, and the impetus behind JohnH's dual gang design, is that the optimal component values change over the range of the volume pot. For example: a treble bleed consisting only of a single capacitor in the region of around 100pF would give results closest to '50s wiring at low volume settings (roughly 3 and below on a standard 10% log taper pot) — however such a small value has very little impact upon the sound at higher volume settings. My usual suggestion is then to switch a 500k volume pot for a 250k pot and, in order to keep the same loading at maximum, also switch the tone to a no-load pot (which also allows it to be 250k which is my preference) — this helps retain treble in the upper portion of the volume control.

With both switches, from '50s to modern and from 500k to 250k, the volume is subtly shifted closer to its true taper. Just as adding a parallel resistor between the wiper & 'upper' lug of the volume pot (as with some treble bleeds) shifts the taper towards that of a linear pot, the following input impedance (and the 500k of the tone pot when using '50s wiring) is bridging the wiper to the 'lower' lug (ground), thus has the opposite effect: shifting the taper to be slightly more logarithmic (a 30% "vintage" taper pot wired '50s style is closer to a modern wired 20%—25% pot).

Anyway, my point being that maybe the best way to emulate '50s wiring is to forget about treble bleeds and instead wire a fixed 500k or 250k resistor (as appropriate) 'after' the volume control in the place where '50s wiring would dictate the tone control would reside, then wire a no-load tone pot in the modern fashion. With the tone pot maxed you would then have what is essentially equivalent to '50s wiring, or exactly equivalent if you (were to care enough about frequencies lower than the range of the instrument, and) included an additional tone cap in series with the virtual '50s tone control (the fixed resistor). The most notable potential issue would be that when the tone pot did drop in (stopped being no-load), the sum loading (at least, internal to the guitar) would be around 166k (assuming two 500k pots + 500k resistor) rather than around 250k of just two regular pots — essentially seeming like the tone pot skipped from 10 directly down to about 7 or 8. For me this wouldn't be an issue as I don't tend to notice a huge deal of change in the upper 50% of the tone range (especially with a 500k pot, which is why I prefer 250k) — and even if not perfect it certainly won't be worse than the behaviour of the original '50s tone control.

[asdaven]

Feb 23, 2023 20:52:01 GMT -5 Yogi B said:

Feb 23, 2023 10:50:29 GMT -5 asdaven said:

But I love the effect the 50s wiring has but I cant live with the tone pot turning down the volume. But with the tone dimed on 10, I really liked the volume roll off. I'm just trying replicate the roll off with 50s wiring with a treble bleed as close as possible.

Does the solution need to be a treble bleed?

The trouble with treble bleeds, and the impetus behind JohnH's dual gang design, is that the optimal component values change over the range of the volume pot. For example: a treble bleed consisting only of a single capacitor in the region of around 100pF would give results closest to '50s wiring at low volume settings (roughly 3 and below on a standard 10% log taper pot) — however such a small value has very little impact upon the sound at higher volume settings. My usual suggestion is then to switch a 500k volume pot for a 250k pot and, in order to keep the same loading at maximum, also switch the tone to a no-load pot (which also allows it to be 250k which is my preference) — this helps retain treble in the upper portion of the volume control.

With both switches, from '50s to modern and from 500k to 250k, the volume is subtly shifted closer to its true taper. Just as adding a parallel resistor between the wiper & 'upper' lug of the volume pot (as with some treble bleeds) shifts the taper towards that of a linear pot, the following input impedance (and the 500k of the tone pot when using '50s wiring) is bridging the wiper to the 'lower' lug (ground), thus has the opposite effect: shifting the taper to be slightly more logarithmic (a 30% "vintage" taper pot wired '50s style is closer to a modern wired 20%—25% pot).

Anyway, my point being that maybe the best way to emulate '50s wiring is to forget about treble bleeds and instead wire a fixed 500k or 250k resistor (as appropriate) 'after' the volume control in the place where '50s wiring would dictate the tone control would reside, then wire a no-load tone pot in the modern fashion. With the tone pot maxed you would then have what is essentially equivalent to '50s wiring, or exactly equivalent if you (were to care enough about frequencies lower than the range of the instrument, and) included an additional tone cap in series with the virtual '50s tone control (the fixed resistor). The most notable potential issue would be that when the tone pot did drop in (stopped being no-load), the sum loading (at least, internal to the guitar) would be around 166k (assuming two 500k pots + 500k resistor) rather than around 250k of just two regular pots — essentially seeming like the tone pot skipped from 10 directly down to about 7 or 8. For me this wouldn't be an issue as I don't tend to notice a huge deal of change in the upper 50% of the tone range (especially with a 500k pot, which is why I prefer 250k) — and even if not perfect it certainly won't be worse than the behaviour of the original '50s tone control.

Well maybe a very small value capacitor would be worth a shot? My goal is to prevent the volume turning down to mud lower down and really maybe get some more sound further down into the volume. Its not maintaining full treble all the way down.

[asdaven]

Has anybody tried a treble bleed with 2 capacitors in parallel or series? Using a higher value capacitor instead of a resistor?

[sumgai]

Mar 2, 2023 13:27:28 GMT -5 asdaven said:

Has anybody tried a treble bleed with 2 capacitors in parallel or series? Using a higher value capacitor instead of a resistor?

What would be the benefit of doing this? Or as much to the point, what is your goal that you contemplate this as a potential solution?

I can't speak for anyone else here, but I've not done this, with one exception.  Years ago I built a circuit for a customer whereby he wanted to switch between treble bleed caps using the second half of his standard Tele switch.  As he went from a Gibson mini-humbucker in the Neck position (which I installed for him) to the Tele Bridge pup, he wanted the treble bleed to act more quickly on the Bridge unit, and more slowly on the humbucker.  The inherent problem of course was that in the middle position, both caps were in play. He said he didn't mind, as he almost never used that combo anyway.

It worked as he wanted it, even though I thought it was overkill.  But his money was good, so.....

HTH





sumgai

[bluesman13]

in adding a treble bleed, I'm using a .01uf cap with a 150k resister wired in parallel. Does it make a difference which lug of the pot the resister goes go? It appears on the Kinman version, the resistor attaches to the left (or output lug) of the vol pot, however I've seen diagrams where it attaches to the middle lug. Is there a preference or a difference? thanks, Steve

[JohnH]

That'd be a 0.001uF cap rather than a 0.01

The cap and resistor are both wired from the middle volume pot lug to the hot outer lug. This is the parallel version, which works best.

Kinman had a version where cap and resistor were in series, not as good IMO. But for that, the order of cap and resistor makes no difference.

[bluesman13]

Having bought a new Fender telecaster, I had to do some re-wiring and noticed that Fender is using a PCB treble bleed circuit (Fender part #7711092001 (rev A)). The R1 capacitor is labeled as "2002" and R2 as "1503" (not sure what that means) and C1 has nothing. See attached picture. During my re-wire, I had to remove the treble bleed circuit, and the gold covering came off, rendering it (I think) unusable. In any case, I measured the values, as I was curious what value capacitor and resister Fender had chosen. Using my trusty multimeter, I measured (in ohms): R1=150; R2=20, C1=150. I thought I read somewhere that C1 was empty, are there two capacitors? I was thinking that perhaps C1 is reflecting the value of R1?

I replaced the Fender supplied treble bleed, with a homemade unit of a .001uf capacitor and 150k resistor, but I was wondering if the treble bleed circuit can *increase* the baseline treble in comparison to no TB circuit at all? (I think the answer is likely no, but thought I would ask)

[reTrEaD]

Nov 13, 2023 16:34:42 GMT -5 bluesman13 said:

I was wondering if the treble bleed circuit can *increase* the baseline treble in comparison to no TB circuit at all? (I think the answer is likely no, but thought I would ask)

Let's clarify what you mean by 'baseline treble'. Do you mean the amount of treble when the volume is at 10? If so, no. The treble bleed network is placed between the CW lug and the wiper of the volume pot. When the volume is at 10, there is (or at least should be) no resistance between those two terminals. You can put anything you want between those terminals and it won't change anything when the volume is at 10.

[stevewf]

Thanks for the photo. Based on the traces that I think I see in the PCB, and on this article (stratocasterdesign.com), here's a try at a schematic.

I've lettered some points in the diagram to talk about what's getting measured.

bluesman, when you're using a multimeter to measure the capacitor, are you setting it to read resistance, and touching the probes to points E & F (either side of the capacitor)? Doing that won't give you the value of c1, but rather it'll will give you the resistance of R1, i.e. 150KΩ

There are two parts of the problem:
Measuring at point E is the same as using point C. Maybe that can be seen in the diagram above. On the PCB, that means the touching the probe one side of C1 is the same as touching the same side of R1. The same goes for the other sides of C1 & R1. That's part of the reason you get two identical readings - you're actually reading the same thing in both cases.

The other part of the problem: the multimeter can read resistances, but when measuring the capacitor, you're looking for capacitance. Most handheld multimeters don't read capacitance, or at least not the small values in a guitar. So if you got a LCR meter that can read small values of capacitance, then you could use points C/E & D/F... but does the presence of R1 in parallel confound things when trying to take that measurement? I don't know the answer. Maybe our better EE forum members can say.

The good news: using your multimeter, you can see if the Fender TB unit is ok despite breaking the foil (not sure what that means, but maybe it doesn't matter). Using the same setting on your multimeter, touch the solder pads (bottom, in the photo), one pad with each of the multimeter's probes. If it reads 170KΩ, then I'd say it's unlikely that your disassembly broke the unit. If it reads infinite resistance, then the TB unit won't work (i.e. won't have any effect), and I'm guessing that the broken foil is one of the traces on the PCB. Again, better if this method of checking gets verified by the more knowledgable. Repair would depend on the detailed nature of the damage.

[bluesman13]

Nov 14, 2023 2:46:23 GMT -5 stevewf said:

The good news: using your multimeter, you can see if the Fender TB unit is ok despite breaking the foil (not sure what that means, but maybe it doesn't matter). Using the same setting on your multimeter, touch the solder pads (bottom, in the photo), one pad with each of the multimeter's probes. If it reads 170KΩ, then I'd say it's unlikely that your disassembly broke the unit. If it reads infinite resistance, then the TB unit won't work (i.e. won't have any effect), and I'm guessing that the broken foil is one of the traces on the PCB. Again, better if this method of checking gets verified by the more knowledgable. Repair would depend on the detailed nature of the damage.

Hey Steve,

I apologize - I'm a novice electrical person :-). Here is a picture of the back of the TB unit - there is gold covering on one side that is missing from the other. It came off the unit when I desodlered the wires, so I'm not sure, without that, if there is any conductivity due to the absence of the gold piece? or does the solder do that? Using the multimeter method you suggested, I got a reading of 170k ohms (so, I guess it works?). thanks so much for your reply! Steve

[bluesman13]

Nov 13, 2023 17:53:39 GMT -5 reTrEaD said:

Nov 13, 2023 16:34:42 GMT -5 bluesman13 said:

I was wondering if the treble bleed circuit can *increase* the baseline treble in comparison to no TB circuit at all? (I think the answer is likely no, but thought I would ask)

Let's clarify what you mean by 'baseline treble'. Do you mean the amount of treble when the volume is at 10? If so, no. The treble bleed network is placed between the CW lug and the wiper of the volume pot. When the volume is at 10, there is (or at least should be) no resistance between those two terminals. You can put anything you want between those terminals and it won't change anything when the volume is at 10.

makes sense. thanks for the clarification.

[stevewf]

Nov 14, 2023 16:01:49 GMT -5 bluesman13 said:

Hey Steve,
Using the multimeter method you suggested, I got a reading of 170k ohms (so, I guess it works?).

Looks to me that you can still use it, as long as you can solder the volume pot's lugs to the same spot(s) that you tested with the multimeter.

You can check it mid-installation.
First, with the vol pot unsoldered to anything else, turn it to zero and measure the resistance between the Hot and Middle lugs. Jot the findings.
Then, the following check should be done after the TB is soldered to the Vol pot, and before the resulting assembly gets soldered to any other components. Again, use the Hot and Middle lugs, and, again, with the vol pot turned all the way to zero. The expected values depend of the resistance of the vol pot, recorded earlier:
 - for a 250KΩ pot, it should test at about about 100KΩ . The arithmetic behind it is   1 / ((1/170KΩ) + (1/250KΩ)) <== substitute your jotted measurement instead of 250KΩ
 - for a 500KΩ pot, about 125KΩ, from   1 / ((170KΩ) + (1/500KΩ))
If you see a value that's far higher (like approx 250KΩ or 500KΩ), then the TB is not connected.

[reTrEaD]

Hey JohnH , this was in my youtube feed:



Does the 'mystery' treble bleed look familiar?

[JohnH]

Nov 15, 2023 6:26:32 GMT -5 reTrEaD said:

Hey JohnH , this was in my youtube feed:



Does the 'mystery' treble bleed look familiar?

Yes indeed, and you saw it all here first!

Meanwhile, 13 years earlier, here is the 'Mystery' TB:



See page 3 of this thread.

I will also note that before this thread, the standard recipe on the internet for the Parallel TB had a 1nF with 220k. 220k causes some thinning out as to roll down, and 150k proved to be better.

The one he called Parish looks to be one of the Fender 'Tonesaver' recipes.

It's a good video, no surprises though.

[stevewf]

Nov 15, 2023 6:26:32 GMT -5 reTrEaD said:

Hey JohnH , this was in my youtube feed:



Does the 'mystery' treble bleed look familiar?

...and the "Parish" looks to be identical to the Fender TB (posts #165 and #167), so I draw bluesman13's attention.

[bluesman13]

Nov 14, 2023 2:46:23 GMT -5 stevewf said:

Thanks for the photo. Based on the traces that I think I see in the PCB, and on this article (stratocasterdesign.com), here's a try at a schematic.

I've lettered some points in the diagram to talk about what's getting measured.

Hey Steve, I was looking at his today, and I'm not understanding where the 1.2nf came from. I enjoyed the video and really like the little gizmo he made for trying the different setups out.

For anyone who just wants the specifics of his different TB circuits, I screencapped them and posted them here:

[stevewf]

Nov 16, 2023 19:30:43 GMT -5 bluesman13 said:

Hey Steve, I was looking at his today, and I'm not understanding where the 1.2nf came from.

Since the value of the cap wasn't visible in that photo you provided, I got that value from stratocasterdesign.com.
"1.2nF" and "1N2" are two ways of stating the same value. So we have two sources that agree on the value of the cap and resistors that come in a Fender TB, and two that agree on the circuit design.

[bluesman13]

oh ok, I understand - that's the bit you were saying that my multimeter doesn't measure capacitance? And, is the capacitor what is installed in C1? Sorry, if I'm being Captain Obvious....

[stevewf]

Nov 19, 2023 13:19:34 GMT -5 bluesman13 said:

oh ok, I understand - that's the bit you were saying that my multimeter doesn't measure capacitance?

What I meant was that capacitors used in guitars tend to be of pretty small value, smaller than most of the basic multimeters are capable of measuring. An LCR meter is better at that, but they tend to cost a lot more than multimeters. Useful for figuring out what's in a circuit.

In general, I think most ppl can get precise enough by wiring up the guitar, playing it and using the ears. Maybe the guitar can be wired up so that the cap (or whatever component) is temporarily outside of the pickguard/cavity. That would make it quick to swap differently valued components, and ear-test again. This method's useful for finding what sounds good (as opposed to figuring out what's in a circuit).

And, is the capacitor what is installed in C1? Sorry, if I'm being Captain Obvious....

Yes, in your photo in post#165, I believe that C1 is probably a 1N2 capacitor (or "1.2nF").

[col]

Hi JohnH

If the treble bleed pot in 'D. Improved' circuit was 1meg (or, alternatively, 2meg), and the volume pot still 500k, how would this affect the appropriate values for the resistor and cap? Would they be increased proportionately, or is it not that simple?

[JohnH]

May 6, 2024 15:33:40 GMT -5 col said:

Hi JohnH

If the treble bleed pot in 'D. Improved' circuit was 1meg (or, alternatively, 2meg), and the volume pot still 500k, how would this affect the appropriate values for the resistor and cap? Would they be increased proportionately, or is it not that simple?

hi col , as you might guess, the simple answer is that it's not that simple!

The two pots are intended to be the two halves of a dual-ganged volume control. Really the main volume part should be not higher than 500k or else treble gets even harder to control. For the bleed part, 500k has about the right sweep. To change it would throw this off, as well as needing go open up the pot and change the wafer.

Really, the difference between the Type D version, and a simple parallel treble bleed or an R and C is very marginal. You can see what's in the graph but it's doubtful whether you'd hear it, and both work very well.