Do volume controls on guitars simply limit output

[Sheepdog1969]

Not being knowledgeable about how guitar volume controls function, I am wondering if they simply restrict output.  When volume controls are at their max, does this setting produce the full and complete translation of the strings vibrations into electrical energy via the magnet/coil assembly in the pickups, meaning turning down the volume controls just limits output? Do we not really, "Turn our guitar volume up", with the controls on our guitars, but only turn them down? (I am not talking about volume controls on amps, just the "pots" on the guitar) I ask this because there is lots of talk about swapping out pups to achieve better tone, but not much about pots. (Note, I am only talking about passive pickups) If volume controls indeed function as signal limiters, how accurately do they reduce the entirety of the harmonic spectrum throughout their range, (max to min sweep)? Thoughts?     

[ksdaddy]

Yes, they only reduce the output by shunting some of the signal to ground. Different value volume pots, besides having different ‘sweep’ characteristics, can affect the highs. A 1 Meg pot will allow more highs to pass through. I can’t explain why, as I’m not educated in electronics, I just know it to be true. And the volume and tone pots, just being “in the circuit”, will affect the output, even if simply turned all the way up. Some guitars have had a bypass switch installed, where the pickup(s) go directly to the output jack. I don’t know if my ears would notice the difference but some people claim it matters. 

[ksdaddy]

1 hour ago, Sheepdog1969 said:

 If volume controls indeed function as signal limiters, how accurately do they reduce the entirety of the harmonic spectrum throughout their range, (max to min sweep)?    

Poorly. As the volume is rolled down, some of the highs disappear. This is why Leo Fender put a 0.001 capacitor across the volume control. Again, I know nothing about “why”, but the effect of this cap is we don’t hear as much of a loss in treble when the volume is rolled back. In fact, it can give a thinner, clearer tone. It’s very useful in shaping one’s tone in a passive manner. I believe it’s technically called a treble bleed. Lately people have used a more elaborate setup with three components or so, a cap and a resistor or two, I don’t recall. If it is superior to Leo’s single little cap, I couldn’t prove it. I wouldn’t dream of building/rebuilding a Fenderesque guitar without that cap. I have not tried incorporating it into a humbucker fitted guitar. 

[Sgt. Pepper]

1 hour ago, ksdaddy said:

Yes, they only reduce the output by shunting some of the signal to ground. 

I posted that is how it works on this very forum ages ago, and told I was stupid and that's not how it works. Either we a both stupid, or um yes that is how it does it. Look at the circuit and learn how electricity and electronics work. 

[ksdaddy]

I say we just claim stupid and people won’t expect much of us. 

[Sgt. Pepper]

6 minutes ago, ksdaddy said:

I say we just claim stupid and people won’t expect much of us. 

I'm considered stupid in the eyes of most here cause I'm not fan of the guitars this forum supports.

[merciful-evans]

3 hours ago, Sgt. Pepper said:

 Look at the circuit and learn how electricity and electronics work. 

I've looked. I didn't learn anything. I think those little wires are magic things that make it loud.

[Sgt. Pepper]

2 hours ago, merciful-evans said:

I've looked. I didn't learn anything. I think those little wires are magic things that make it loud.

The cool colors keep the magic in. See smoke and the genie is out. Game over. Nothing more to see. You don’t have to go home, but you can’t stay here.

[sparquelito]

I like this video to explain in layman's terms what's going on.
 

 

[Notes_Norton]

They are variable resistors.

Almost all volume knobs are variable resistors, whether they are on your guitar, amp, radio, stereo set, etc.

Here is how they work...

https://www.circuitbasics.com/variable-resistors/

I like to have control of my volume, so I can turn the guitar up when it's time to solo, turn it down when what I'm playing should be in the background, and so on. But when I turn it up, in reality, I'm just turning it down less.

Notes ♫

 

[Sgt. Pepper]

A pot has 3 posts, a variable resistor has 2. A pot can be used as a variable resistor, but not the other way around. 

[OrdinaryNimda]

It functions as a limiter of energy throughput. The highest frequencies are impacted the most.

[Sgt. Pepper]

1 hour ago, OrdinaryNimda said:

It functions as a limiter of energy throughput. The highest frequencies are impacted the most.

It all comes down also to what you have in your guitar. The guitar is an RLC circuit. R - Resistive (Pots), L - Inductive (Pups) and C - Capacitive (Caps). And absolutely frequency affects the caps and inductors in the opposite direction. Its all math and formulas which is hard. I had electrical theory shoved into my brain ages ago by the military. 

Edited July 26, 2023 by Sgt. Pepper

[Notes_Norton]

13 hours ago, Sgt. Pepper said:

A pot has 3 posts, a variable resistor has 2. A pot can be used as a variable resistor, but not the other way around. 

I don't know if they changed it, but when I took electronics in school, a potentiometer was a type of variable resistor.

But I went to school a looooong time ago, so they may have changed that classification.

Notes ♫

[kidblast]

yea,, it's for real.

The front pickup "ONLY" on my Jaguar does not sound the same when I engage the "Jazz" circuit, which is the front pickup with a dedicated tone and volume.  (The top set of controls over the neck pickup on a jag.)

 

[Sgt. Pepper]

1 hour ago, Notes_Norton said:

I don't know if they changed it, but when I took electronics in school, a potentiometer was a type of variable resistor.

But I went to school a looooong time ago, so they may have changed that classification.

Notes ♫

It certainly is, but having 3 posts it divides the voltage according to where you turn the knob and where the whipper is. A variable resistor just drop the voltage across the whole resistor depending on where it set, but you can vary it. If you only use 2 posts of a pot, the whipper and one of the others its basically just variable resistor. Connect another wire to it an use all three and now is working as a pot.

And pots can be linear or audio pots that's another who ordeal off how the turns on the pot affect the output. I think it has to with how its wound inside. I'm just a dumb electrician and know what the military taught me. I'm no EE.

Edited July 26, 2023 by Sgt. Pepper

[OrdinaryNimda]

4 hours ago, Sgt. Pepper said:

It all comes down also to what you have in your guitar. The guitar is an RLC circuit. R - Resistive (Pots), L - Inductive (Pups) and C - Capacitive (Caps). And absolutely frequency affects the caps and inductors in the opposite direction. Its all math and formulas which is hard. I had electrical theory shoved into my brain ages ago by the military. 

Very true, we are talking here only about "passive" circuits, with the only energy source input into the system being the "L". All other electrical elements (including the wires, though minimally) take some energy away before it reaches the Amp. 

Theory we all get in schools of all sorts, it's needed and is good to have in the brain. But it always has to be followed up by real world scenarios. It took me quite some time (and heavy thinking 😅), that for example a Volume pedal also works in this "one way only" fashion. It only takes volume away from the equation and never increases it. It's (basically) just a resistor, like the Pots in the guitar. And all the other elements, including the Caps, take some or more energy away.

[Sgt. Pepper]

4 minutes ago, OrdinaryNimda said:

Very true, we are talking here only about "passive" circuits, with the only energy source input into the system being the "L". All other electrical elements (including the wires, though minimally) take some energy away before it reaches the Amp. 

Theory we all get in schools of all sorts, it's needed and is good to have in the brain. But it always has to be followed up by real world scenarios. It took me quite some time (and heavy thinking 😅), that for example a Volume pedal also works in this "one way only" fashion. It only takes volume away from the equation and never increases it. It's (basically) just a resistor, like the Pots in the guitar. And all the other elements, including the Caps, take some or more energy away.

It all does start at the pickup, being a coil or the L. That is the entire reason you electric guitarist need an amp. When strumming real hard you may produce a volt or so. 

Why in the hell did they chose L for inductance anyway?

Edited July 26, 2023 by Sgt. Pepper

[OrdinaryNimda]

2 hours ago, Notes_Norton said:

I don't know if they changed it, but when I took electronics in school, a potentiometer was a type of variable resistor.

But I went to school a looooong time ago, so they may have changed that classification.

Notes ♫

A pot is a variable resistor. Nothing has changed with regards to electro-magnetism.

OK, maybe it's been proven by eperiments that Neutrinos have mass, and there's something fishy going on with Muons, but those don't appear in guitar circuits. 😄

[OrdinaryNimda]

2 minutes ago, Sgt. Pepper said:

It all does start at the pickup, being a coil or the L. That is the entire reason you electric guitarist need an amp. When strumming real hard you may produce a volt or so. 

I actually have never measured this voltage. I know it's really miniscule, so readily available for all sorts of distortion from the environment (dropouts, hum, thumderstorms, solar activity, air-conditioner in some house down the street...)

[Sgt. Pepper]

8 minutes ago, OrdinaryNimda said:

I actually have never measured this voltage. I know it's really miniscule, so readily available for all sorts of distortion from the environment (dropouts, hum, thumderstorms, solar activity, air-conditioner in some house down the street...)

I did it once and I think punishing the guitar I got about a volt. Now I only play acoustics.

Edited July 26, 2023 by Sgt. Pepper

[OrdinaryNimda]

24 minutes ago, Sgt. Pepper said:

I did it once and I think punishing the guitar I got about a volt. Now I only play acoustics.

Yeah, tremendous all-natural sound. 👍

[Notes_Norton]

Thanks Sgt. Pepper & OrdinaryNimda

I'm aware of the two different kinds of Variable Resistors, and in the most likely type in a guitar would be the potentiometer. But I don't know for certain. My Parker has a preamp inside, to boost the piezo signal and mix with the mag pickups, and I would guess a pot, but never bothered to look. So for me, it's safer to use the collective noun.

I'm glad they haven't changed the nomenclature. When I was very young, some teachers still called capacitors 'condensers'.

But electronics and I parted ways after school, as I found it a lot more fun to make a living playing music. I did take a job as a Field Engineer for a Cable TV gear manufacturer when I tried out what it was to be normal. Actually the Engineer was an inflated title, it was more technician, and at the 'black box' level. Any failed components, amplifiers, filters, equalizers, and so on were modular. Swap them out, so the system is working ASAP and send them to the bench techs. So I haven't dealt with much more than replacing a phone jack on a guitar cable since then.

Back on topic.

There is more than one right way to do this.

I know guys who run their guitars with max output and make all volume adjustments on the amp, or a foot pedal.

On my Parker (gigging guitar) the master volume is right next to the bridge, so I can get to it easily while I'm playing. So I run it physically about 2/3 up, and it's variable gain, (Tapered/LOG) so I have plenty of wiggle room. I can crank it up for solos, turn it down for mellow music, and adjust during the song to stay in balance.

Guitar isn't my primary instrument, sax/wind synthesizer is. But I probably play about 1/4 or more songs on the guitar for any gig, depending on what type of songs the audience needs.

Whatever gets you through the night is right.

 

Notes ♫

[Sgt. Pepper]

Your not gonna find a variable resistor in a passive guitar circuit. There what 10 to 15 bucks. What you think Gibson is paying for a crate of them? It’s like digital stuff in chips it’s easier to use NAND Gates and make it simulate other gates. Then the program only has to make one gate. Better Faster Cheaper. The dumb stuff I remember.

Edited July 28, 2023 by Sgt. Pepper

[merciful-evans]

13 hours ago, Notes_Norton said:

 

I know guys who run their guitars with max output and make all volume adjustments on the amp, or a foot pedal.

Notes ♫

That's me. (Hardly touched a knob -except by accident).

Or rather it was me, because I don't gig any more. So its only in the last couple of years I've discovered those little knobs and learned which ones are which.