Suggestion For Improved Tone Control

[Channelman]

I've never been happy with the 'Top Cut' type tone control on most of the guitars I've owned.
I would like to suggest this circuit attached here.

This circuit acts, when the tone pot is turned down, exactly like the 'normal' tone control but
at the other end provides the 'treble bleed', which gives a 'treble boost 'effect. Full adjustable
to get the sound you want.

So, you get treble cut and boost for the cost of one extra capacitor.

Regards Channelman

[sumgai]

Channelman, to the forums. But you should know, I think you've made a rather strong initial post, it fairly begs for rebuttal. I have this sense of impending debate, but I'm not gonna start it.

Tickets! Tickets! Step up right here and getcher tickets!!


sumgai

[UnklMickey]

sumgai said:

... I have this sense of impending debate, but I'm not gonna start it....

keep that up, and we'll change your name to Nancy.


[quote author=channelman board=wiring thread=1158695951
post=1158695951] I've never been happy with the 'Top Cut' type tone control on most of the guitars I've owned... [/quote]

hi Channelman,

welcome to Guitarnuts2.


right-off, i agree with you about guitar tone controls, in general.

but........

this circuit essentially puts the tone cut after the volume control.

IMHO, that makes things worse.

the amount of cut now increases as you turn the volume down.

that is somewhat mitigated by the treble bleed at the other end of the pot.

so...........

one might be able to find a position on the tone control that has the right amount of effect, even when the volume is reduced.

then again, one might have better success with a conventional tone control before the volume control and a fixed treble bleed network between the high and wiper of the volume control.

certainly a pspice simulation would give up a better idea of the usability of this circuit.

'til then, i'll only say ............... maybe.



thanks for an interesting topic.

unk

[ChrisK]

This shows a high and low cut structure. While this used a blend pot for high-cut or low-cut sharing a common (choice of three) capacitor, one can see that high-cut is to common and low cut is in series with the signal path. You may have to use a parallel resistor across the low-cut series pot if too much signal is attenuated at the max setting.

The SPDT center off switch selects 0.047uF, 0.022uF, and about 0.015uF (the "woman tone"
unk; Nah-nah-nah-nah-nah-nah, nah-nah-nah-nah-nah-nah ) when in the center position. Choose what you want for each control. The higher the value, the more the highs are cut and the less the lows are blocked.

'Course, you could use a 0.1 uF for the "man tone". ;D

[Channelman]

@unk
I did run it thru a Spice simulator, before deciding on the values
to use in one of my guitars.
Before I fitted it I always found that I left the normal tone control
at the position which gave no treble cut. I was going to fit a fixed
'treble bleed' cap to the volume control when I thought of this
which effectivly gives me an adjustable 'treble bleed' without
loosing the cut, if I did ever want it. Also, no extra holes, or
fancy dual pots.
I actually finished up using 2.2nF for the bleed cap and 4.7nF for
treble cut cap with humbuckers but I might put different values
in my Am Strat.
Channelman

[UnklMickey]

chrisk said:

...(the "woman tone"
unk; Nah-nah-nah-nah-nah-nah, nah-nah-nah-nah-nah-nah )....

[UnklMickey]

channelman said:

@unk
I did run it thru a Spice simulator...

hi Channelman,

that's great.

could you post images of the graphs?


thanks,

unk

[ChrisK]

You realize of course, that this is a ploy to steal your collection of animations!

[UnklMickey]

thas kool, it ain't no crime to steal from a thief.

[ranchtooth]

I've also never been happy with most stock tone controls. Thats why I rip them out and put in an active preamp. Huzzah.

[JohnH]

Hi Channelman - welcome to GN2, we need more like you

The rest of you: watch out! this is a fellow who seems to know how to work out what he wants!

John

[sumgai]

unk,

...
keep that up, and we'll change your name to Nancy.

Don't you dare do that, Sluggo, or I'll tell Aunt Fritzie on you!

;D

[sumgai]

I zero'ed in more on the "..... boost" portion of Channelman's spiel. I thought for sure that would fire up somebody!

[Channelman]

could you post images of the graphs? unk

Here ya go unk.
These were taken with a 500k VOL pot set at 30% (which would
be about a 6 to 7 setting on a normal 0-10 guitar LOG pot.
The TONE pot was also 500k, the top cap was 1nF and the
bottom cap was 4.7nF. ('Normal Tone controls in guitars use 20nF
which I find waaaaaaaaaaaaay too much)
Here are three graphs showing 'boost', 'level' and 'cut'
Increasing the 4.7nF to 10 or 20 nF just drags the lower curve
even lower without affecting the 'boost' setting.
Channelman

[ux4484]

sumgai said:

Don't you dare do that, Sluggo, or I'll tell Aunt Fritzie on you!

;D

*sigh*

Aunt Fritzie....first woman I ever loved .

[UnklMickey]

sumgai said:

I zero'ed in more on the "..... boost" portion of Channelman's spiel. I thought for sure that would fire up somebody!

he pretty much pre-empted that by using 'quotes':

'treble boost '

channelman said:

...('Normal Tone controls in guitars use 20nF
which I find waaaaaaaaaaaaay too much)...

i agree.

with the tone control before the volume, 20nF is a bit high.

with the tone control after the volume.........fuggetaboutit.


thanks for posting the graphs.

the choice of -10dB (volume) is a good point for analysis for a single data point.

more of the story would be told, with a couple more volume settings.

the scale only goes down to -20dB, so i'm not sure if using lower volume settings can be accommodated.

in general the graphs look okay, but i'm still a bit concerned about what will happen when the volume is changed, particularly when the tone is set at 5%.

i suspect the curves will change dramatically.

we would expect (and want) that to happen in the 'treble boost' setting.

but, it will likely require some fussing with the tone control when it's at the 'cut' and perhaps even at the 'neutral' settings.

i wonder if it might be a bit more manageable, if you added a resistor at the bottom end of the tone pot.

that would limit the amount of cut.

it still won't keep the curve from changing, but it will prevent the cut from getting so excessive.




unk




EDIT:

i just did a "simulation" on the TSC.

200k is too much for the "bottom" resistor.

50k seems a bit better.

but........................

i had an idea on something that might be even better.

i'll be back in a few with more info.

[sumgai]

Channelman,

One question: Do you consider a rise to near zero loss a boost?

I can see that graphically, it looks like the anwswer would be "yes", but then when one observes that starting point is nearly 12dB down......... I don't know how you reckon things in your neck of the woods, but around these parts, -12dB is a helluva loss to insert in the first place!

Moral of the story: you can't get something for nothing, not even in the amazing world of GuitarNutz! ;D


sumgai

p.s. John, I like Channelman's graphs, they make a lot more sense for this kind of discussion than millivolts in "log e", or whatever scale it is your graphs use.

[Channelman]

>One question: Do you consider a rise to near zero loss a boost?

Yes, RELATIVELY speaking.
A LOG Volume pot set to around '7' on a guitar gives a -12db attenuation,
which is why I chose it. It's about where I set mine.
Obviously you can't get something for nothing but it's all relative.
Channelman

[UnklMickey]

channelman said:

....Obviously you can't get something for nothing but it's all relative....

tell that to MY relatives.

they always seem to want something for nothing!

.:lol:.



unk

[JohnH]

Channelman - nice work. have you run your model with the pickup resistance (about 6k for single coil) inductance (3H for a hot single) and winding capacitance (I use 200pF - or ignore it)), and also the amp input imedance (1M) and cable capacitance (say 0.8nF for a 20' cable) modelled? Then youd see the full picture - just for interest.

At full volume, only treble cut is available - but I agree that your control is more versatile than a standard tone control. I find that in a passive guitar the sound at full volume is much better than at reduced volume, no matter how much equalisation is built in with treble bleed etc. Adding in those other parts might demonstrate that.

I also agree with you than normal tone caps are too large 10nF or even less works for me.

John

[UnklMickey]

good post John,

a more complex model for the source will tell a more complete tale.

full volume IS a naturally better sound.

i wonder if Channelman likes to keep his volume open part way, to have some "room to grow" when a solo comes up.

i wonder if one of you could run a simulation on this:



i can't configure TSC for this circuit.

i'd really be interested in seeing what the graphs look like if the volume is set for -10dB, and the tone adjusted to "neutral".

then what happens when the volume is set for -3dB and also -20dB.

also of interest would be what the curves look like, with those 3 volume settings.... with the tone at minimum and maximum.


i always thought a 1nF treble bleed cap was a bit much, and putting a resistor in parallel with it, also changes the operation of the volume pot.

this might be an interesting twist on things.

then again..................



unk

[Channelman]

OK, I'll do some more sims tomorrow....just got back from a pool match.
I did my original sims with a 5H + 5kohm pickup in series with the source
and a 500pF load for the cable. I just didn't want to confuse the issue,
because what ever happens these result add to the original.
Without anything the 'top end' is going to be down due to the inductance
and the cable capactance (unless you go active and I don't like batteries
in guitars).
I'll be back tomorrow.
Channelman

[UnklMickey]

channelman said:

...(unless you go active and I don't like batteries
in guitars)....

i DO agree........................although, be prepared to get a bit of flak from JohnH, Dunkelfalke, and CheshireCat.

all well intentioned, and in a positive light ................ but they probably will refer to us as dinosaurs.

channelman said:

...I did my original sims with a 5H + 5kohm pickup in series with the source
and a 500pF load for the cable. I just didn't want to confuse the issue,
because what ever happens these result add to the original....

i completely understand that reasoning.

you might do a sim of just a volume control with no tone control, and the model that JohnH uses.

that way when you compare the graphs with the results from the tone control circuit, it will have some context.


unk

[Channelman]

>you might do a sim of just a volume control with no tone control, and the model that JohnH uses

Here ya go, JohnH values, for pickup, cable and amp, no tone.
Volume settings 90%, 70%, 50% 30% and 10%
I'll do some more tomorrow (whoa... that's later today now)
using unk's circuit and values.

Channelman

[Channelman]

@unk, here's your circuit, simulated as requested.


I've done at the three requested volume settings and a full sweep on the tone control.


Cheers,
Channelman

[UnklMickey]

thank you Channelman,

+1 for making those graphs.


this does tell me quite a bit about how the circuit will function.

this thing does just about exactly what i was looking for, on the 'boost' end.

i did want to take much of the cut out of this circuit.

but, it looks like i've pretty much castrated it.


if i'm not being too much of a PITA, could you run a sim on this next version?


i'd really like to see a sweep of the volume control, if that's possible.

as much info as the sweep of the tone control gave, i think a sweep of the volume will tell just a bit more.

i'd like to see 3 graphs:

first, with the tone control at max.

second, with the tone at minimum.

third, (this is a real important one) adjust the volume for about -10dB.
then adjust the tone so it is as close to flat as possible.
now do a sweep of the volume.

if you can set a limit on the lowest volume setting that is displayed, that will probably probably work well.

we don't need to see a 90 db range or anything.

about 0 to -40dB or so, would be my guess for the most usable info.



i'll fully understand if you think i'm just being too 'needy', and don't want to bother with this.

in any case, thanks again for your help so far.


unk

[Channelman]

@unk
I don't think you are going to be happy with this one either.
I've done the sims and swept the Volume fro 5% to 95% for
Max Tone, Min Tone and as requested which was about 30%.
I think that you've killed the effect with those 50k resistors,
unless this is the effect you wanted, of course.
Cheers, Channelman

[UnklMickey]

"I think that you've killed the effect with those 50k resistors,
unless this is the effect you wanted, of course."

good one!


actually i am 2/3 happy with this.

the total of 100k makes the 'boost' work exactly the way i was shooting for.

things are reasonably well behaved in the 'neutral' position.

i really missed the mark on the cut, though.


looks like i'll have to do a better job of determining the size resistor i need in series with the wiper, to get a 6~10 dB cut when the volume is at -10dB

then add the balance of the 100k to the top of the pot.


thanks for the help!

unk

[Channelman]

So, here's my latest idea....its a Channelman-Unk Hybrid.
Well, I think it does what I want.
Channelman

[UnklMickey]

mmmmmmm..........................ChUnky! that's a cute name.



still looks too bright for my taste, on the top end.
(i think a +6dB shelf will keep it sounding similar, when the volume is changed between 0dB and -10dB

but it does look like it works well on the bottom end.

i think i like it.

are you interested in seeing what it does, when you run the graphs on it, like you did for my last version?


unk