avoid tone loss with volume knob roll-off?

[chris m.]

Hey, y'all--

I gig with all kinds of guitars-- Tele, Les Paul, Epi Dot (335 copy), Strat-- always through tube amps, mostly blues and classic rock stuff.

I like to be able to control everything from the volume knob of the guitar-- back off on volume knob for cleaner rhythm at lower level, and crank it up for warm, full sounding bluesy- lead tone.

However, on all of my guitars, as I back off on the volume knob, the tone changes...even if I don't back off that much. Sometimes gets thinner and weaker, sometimes gets muddier.

I know that this is very complex-- a combination of how the signal coming from the guitar changes with volume knob adjustments, and how that signal pushes against the pre-amp tubes and power tubes circuit of a particular amp (in my case always a vintage tube amp-- classic 50@ Marshall JCM800 combo amp, Traynor YGM-3 Fender-ish tube amp, or Fender MusicMaster Bass amp- depending on the venue). But 80% of the time, even with a lot of adjusting the amp settings, I end up with a bit of a compromise and am satisfied but not totally happy with both rhythm and lead tones.

I know that improvements can be made by messing with the caps and resistors that are in the guitar's circuits...but don't really have a clue where to start. For example, Gibson has a "Memphis Tone" circuit that supposedly "preserves" tone as volume knob levels change.

Can anybody give me some hints as to how changes in the guitar wiring circuits are typically tweaked to deal with these issues? To be clear, I am extremely happy with how all of my guitars sound with the volume knob dimed-- no pickup changes needed-- just wondering how to avoid tone loss during volume knob roll-back.

Are the typical tweaks to address this pretty similar, whether we're talking Les Pauls, Strats, or Teles?

Thanks--

 

[Chris Leger]

Are the typical tweaks to address this pretty similar, whether we're talking Les Pauls, Strats, or Teles?

Yes. Do a search for "treble bleed mod." In general, you solder in a cap and resistor, whether in parallel or series, to shunt some of the high freq signal across the pot terminals.

Lots of folks have installed this sort of circuit for years and years, in order to preserve the highs when the volume is rolled off, as the higher R of the pots tend to attenuate highs first and foremost.

It's a common mod. You'll find it.

 

[scubadoo]

i don't know much about it but search for threads about treble bleed mods where you have a cap between two of the connections on the volume pot.

 

[tjalla]

By far one of the most simple and organic ways of doing this to my ears is what some call the '50s mod' where the tone pot is wired to the volume pots center lug (usually its soldered to the input lug). Not really doable on a strat since the tone pots both go to switch, but a 5min job on a tele/LP.

No need for caps/resistors, which I usually find objectionable. Immediately reversible if you don't like it. I use this mod almost all the time - I even hook up my strats with a single master vol pot this way - and it really works a treat.

 

[graphs]

If you're going to go the cap route, I highly suggest using a resistor in parrallel. I find it makes the treble bleed much more natural sounding and usable. The cap alone makes it sound too bright/thin as you roll the volume down.

 

[Colin Johnston]

By far one of the most simple and organic ways of doing this to my ears is what some call the '50s mod' where the tone pot is wired to the volume pots center lug (usually its soldered to the input lug). Not really doable on a strat since the tone pots both go to switch, but a 5min job on a tele/LP.

No need for caps/resistors, which I usually find objectionable. Immediately reversible if you don't like it. I use this mod almost all the time - I even hook up my strats with a single master vol pot this way - and it really works a treat.

+1

IMHO this is the most natural "feeling" solution

 

[TelZilla]

By far one of the most simple and organic ways of doing this to my ears is what some call the '50s mod' where the tone pot is wired to the volume pots center lug (usually its soldered to the input lug). Not really doable on a strat since the tone pots both go to switch, but a 5min job on a tele/LP.

No need for caps/resistors, which I usually find objectionable. Immediately reversible if you don't like it. I use this mod almost all the time - I even hook up my strats with a single master vol pot this way - and it really works a treat.

Agreed, that's best for the tele.

I've used the info on projectguitar.com ((link removed)) to do similar mods on strats and LPs and liked the results.

 

[patrickhowell]

On the guitars that are getting dark and muddy, you probably have a standard tone/volume setup.

On the guitars that are getting thin and brittle, they probably have a "treble bleed mod" setup - likely with just a capacitor and no resistor. You can add a cap in parallel or series with a treble bleed cap to lessen the high-end spike as the volume goes down, but this will also change the feel of the control.

Here are the most common options:
1) Standard volume / tone wiring: Less treble as your volume goes down

2) Treble Bleed Cap: More treble as your volume goes down

3) Treble Bleed w/Resistor in series: With the right value resistor, you should have balanced treble as the volume goes down. But this takes a lot of guess and check.

4) Treble Bleed w/Resistor in parallel: Again, balanced treble as the volume goes down, but more guess and check, but some players prefer this approach. Also, this changes the taper of your volume knob.

5) 50's Mod: Most transparent operation of volume knob, easiest mod on Tele/Les Paul, impossible with the strat wiring setup.

 

[neon333]

By far one of the most simple and organic ways of doing this to my ears is what some call the '50s mod' where the tone pot is wired to the volume pots center lug (usually its soldered to the input lug). Not really doable on a strat since the tone pots both go to switch, but a 5min job on a tele/LP.

No need for caps/resistors, which I usually find objectionable. Immediately reversible if you don't like it. I use this mod almost all the time - I even hook up my strats with a single master vol pot this way - and it really works a treat.

Can this mod be done on a tele with a 4 way switch?

 

[mgwhit]

Can this mod be done on a tele with a 4 way switch?

Yes, the 50's mod just affects the way the signal goes from the volume knob to the tone knob. It's entirely post-switch (unless you have a very non-standard wiring).

 

[spankdplank]

+ 1 on the 50's or "Fezz Parka" mod. IMHO, it is far and away the the best sounding and easiest tele volume mod. The .001 treble bleed mod is OK, especially with 500K or 1 meg pots, but it is hard to use live without a 150k or 220K resistor wired in parallel with the .001 cap. With the resistor it works great, especially with 1 meg pots.

 

[DILLIGAF?]

I would have to say a .001 cap in parallel with a 220k resistor works best for me. The tone stays intact when I lower the volume and the sweep seems more gradual. If you do volume swells this may not work for you.

 

[tdowns]

On the guitars that are getting dark and muddy, you probably have a standard tone/volume setup.

On the guitars that are getting thin and brittle, they probably have a "treble bleed mod" setup - likely with just a capacitor and no resistor. You can add a cap in parallel or series with a treble bleed cap to lessen the high-end spike as the volume goes down, but this will also change the feel of the control.

Here are the most common options:
1) Standard volume / tone wiring: Less treble as your volume goes down

2) Treble Bleed Cap: More treble as your volume goes down

3) Treble Bleed w/Resistor in series: With the right value resistor, you should have balanced treble as the volume goes down. But this takes a lot of guess and check.

4) Treble Bleed w/Resistor in parallel: Again, balanced treble as the volume goes down, but more guess and check, but some players prefer this approach. Also, this changes the taper of your volume knob.

5) 50's Mod: Most transparent operation of volume knob, easiest mod on Tele/Les Paul, impossible with the strat wiring setup.

Great summary patrickhowell!!

Can this mod be done on a tele with a 4 way switch?

Yes.


This will drive you crazy because there are so many variables.

1. The volume pot value - The higher the resistance, the more treble gets bypassed as it is turned down. I'll bet you don't have the same volume pots in all your guitars.

2. The cable and the amp - The longer the cable, the greater the capacitance, so the treble loss is greater without a treble bypass cap. The input impedance of the amp will also vary. You may get it right for one cable and amp, and it will differ with another set.

To almost totally fix the problem, an active buffer could be used to 1) drive a low resistance volume pot (10K) and 2) another high input impedance buffer on the output of the volume control. This would result in negligible frequency response change electrically.

But wait, there's more!! Our human ears have a different perception of frequency response at different loudness levels, so you can never get it perfect. See Google search on Fletche Munson Curves.

I'd start be determining the component values of each guitar. The 50s mod may work on some. You can also get a variety of cap values and connect them using alligator clip leads. Experiment until you get the righ one. If you go the route of using a resistor in parallel or series with the treble bypass cap, you can clip on a 500K pot and adjust it for the desired response, disconnect it, read the resistance of the pot where it was set, and install a fixed resistor closest to the measured value.

 

[Musicman85]

Hello,

I have made some simulations regarding this issue and published the results here:
Treble loss with volume roll off

It would be fun to continue and make simulations on the fixes described here. The project is public and anyone is free to make more simulation tests.

 

[SPUDCASTER]

Welcome to the forum.

Since 2009, let's hope ChrisM has solved his issue. Nevertheless, you've provided some good information.

Other members Antigua Tele and Rigatele are into the "science" aspect of this addiction we call Telecaster.

It was good to see an old post by tdowns. A lot of special members have come and gone for various reasons.

Have fun.

 

[Wally]

A linear volume pot will yield a wide range of usable tones. Gibson began using 300K linear pots in their regular production guitars in the early '70's.
Fender introduced a .001mfd treble bypass cap on the Telecaster in 1967. PRS guitars have come with .001mfd caps with a paralleled 150K resistor. I have found that larger caps and smaller resistors can be used to tune that bypass circuit for certain pickups.
The '50's Gibson wiring and the very similar 'Fezz Parka' wiring also yield a wider sweep on the volume pot.

 

[Wrong-Note Rod]

i've said this before, but, to play devils advocate here:

I like the fact that my treble drops when I turn the volume down. I find this very beneficial for ensemble playing, especially with a singer. When I turn the volume down, I lose treble, and that prevents me from competing with whatever other instrument, or singer, is supposed to be the forefront of the band, at that point.

So I never use any of those mods.

 

[Musicman85]

i've said this before, but, to play devils advocate here:

I like the fact that my treble drops when I turn the volume down. I find this very beneficial for ensemble playing, especially with a singer. When I turn the volume down, I lose treble, and that prevents me from competing with whatever other instrument, or singer, is supposed to be the forefront of the band, at that point.

So I never use any of those mods.

Sure, it can be beneficial in many ways. However, maybe the name "volume pot" is somewhat misleading because many people uses it for other purposes.

 

[Musicman85]

A linear volume pot will yield a wide range of usable tones. Gibson began using 300K linear pots in their regular production guitars in the early '70's.
Fender introduced a .001mfd treble bypass cap on the Telecaster in 1967. PRS guitars have come with .001mfd caps with a paralleled 150K resistor. I have found that larger caps and smaller resistors can be used to tune that bypass circuit for certain pickups.
The '50's Gibson wiring and the very similar 'Fezz Parka' wiring also yield a wider sweep on the volume pot.

I will try to simulate how the different setups impact the frequency response.

 

[Wally]

i've said this before, but, to play devils advocate here:

I like the fact that my treble drops when I turn the volume down. I find this very beneficial for ensemble playing, especially with a singer. When I turn the volume down, I lose treble, and that prevents me from competing with whatever other instrument, or singer, is supposed to be the forefront of the band, at that point.

So I never use any of those mods.

Seriously.. but with a friendly smile/chuckle....What if the singer or the instrumentalist is working in the baritone/bass range of things?
IT is all personal.subjective as to how we each run an instrument. I like an hot amp, and I like a volume control that allows me to run overdrive or lively cleans with just a change of the volume control on the guitar and/or a change in pick attack while maintaining the same tonality throughout the range of volume used.
I equate this to a good acoustic guitar/violin.mandolin/standup bass/piano/harp---instrument...I like to hear all of the frequencies that I am playing along with the harmonics that are created when notes are in tune. All good acoustic instruments create harmonics that are not being played. Two or more voices in harmony create harmonics that are not being sung...way up high there. This personal need I have demands a full range for the signal coming out of an electric guitar's circuit and amp that mimics nature, ime and for my tastes.
When I turn down a guitar below '7' on the dial with an unbypassed audio taper pot that has something other than the Gibson '50's wiring, I don't like it. IT is dull and uninviting...like what I fear I will hear when my high end hearing is gone...if it does leave me. Others' mileage may vary.....