Upgrading LP guitar electronics

[soundguruman]

So even if I make a "50s wiring" or remove the tone potentiometer at all and just leave the volume pot, it will still be cutting the frequencies, right? Even those highly-regarded CTS do so, right?
So the only way for it not to cut frequencies is (and not buying the ultra expensive "step" volume controls) is to make a treble bleed mod, do I get it right?

Yes that correct. Just who regards CTS so highly? They look pretty low budget ordinary to me. I would not use CTS personally. I would use Precision Canada if they fit.

[riz]

The potentiometer changes the resistance in the chain. But, for example, if it's a truly 500k potentiometer - is it always 500k at the highest (or lowest) position? If so, then what is the resistance at the lowest (or highest) position? I mean, what is its resistance at 10 and at 0?

If I get it right, the bigger the resistance is, the more signal is passed through the resistor, right? So 1000k potentiometer passes more signal, right? What is then the biggest possible resistance that passes all the signal and does not filter anything out? I mean, if I get it right, 0 resistance means no signal passes, right? Then was is the maximum value were everything comes through? I understand that it's impossible in reality, but I am talking about ideal case. And what is the maximum possible resistance?

Research "no-load pots".

[David Schwab]

"Is it possible to make it work so that if I turn one volume knob all the way down, the other pickup is not turned off?"
No. Not with the switch in the middle position.
Normal guitar wiring is not that way. When both PUs are on, either volume will turn the guitar to 0.

It absolutely IS possible, and every Rickenbacker (guitar and bass) and Jazz bass work exactly this way.

All you have to do is wire up the volume pots differently. Just swap the pickup from the outside lug on the pot to the center lug. Then connect the outside lug to hot.

Now when you turn down one pickup all the way, it wont turn down the other.

[David Schwab]

Research "no-load pots".

Those are only for tone controls. If you put a no load pot in for a volume control you wont have any signal at 10.

[David Schwab]

Could someone please explain me what is the difference between good and bad potentiometers?

Mostly just the taper, which is how fast it changes as you turn it, and durability and how they feel. I have some very cheap pots that feel great and have been working fine for many years. But I generally use Bourns pots, although I don't care for low friction pots, and that's how a lot of them are.

[David Schwab]

There are inductive and non inductive resistor materials. Like for instance a wire wound pot is inductive, and will tend to pick up a lot more external 60 cycle hum. If you dig deep into the manufacturer specification sheets, you will see that some high end controls are intentionally made "non inductive." And therefore, probably have a lot less hum from external sources.
Of course most manufacturers and vendors don't want you to know this, because you will stop buying the cheapo products.
Let me tell ya, it's HARD to buy good controls, because the sellers are hiding the real information. You really gotta do your research!

All pots that are not wire wound are non inductive. Even cheap ones. Who uses wire wound pots for guitars? No one. They are for high power situations. If your pickups were putting out 4 Watts, then you might need it. Its the wound wire that creates an inductor.

You are telling him too much info that doesn't apply to guitars.

[andrius]

http://www.bourns.com/data/global/pd...ng_appnote.pdf

Yes, when you turn the control down the treble drops off, same with all potentiometers basically...
we put a silver mica cap between the wiper and the input of the control to bypass the resistance (100-500pf) this is the same as the bright switch on a fender amp...just no switch, same circuit.
There are also "step" volume controls that are intentionally made so that the treble does not roll off. These cost $$$ and are used in high end hi fi amps.
http://www.percyaudio.com/Catalog.pdf See page 13...just to get the idea.
That is probably the advantage to an active volume, that uses a feedback loop to control the gain instead of a conventional volume circuit.

If the guitar volume potentiometers always lose treble frequencies...I wonder whether the potentiometers used in amps lose treble too. If so, then the lower the volume of the amp, the less clear it sounds, and the only way for it to sound right is to play it on full volume - is that so?

[Steve Conner]

Guitar volume pots lose treble when turned down because they are hooked up to a long cord with lots of capacitance. That doesn't apply so much to amps: the volume control has to drive the input capacitance of the following stage, which is only about 100pF for a 12AX7 tube, and less for solid-state circuits.

Indeed some amps had a "bright cap"- a capacitor across the volume pot similar to the treble bleed guitar wiring. In the absence of any cable capacitance, that overcompensated and gave the amp more treble at part volume than at full volume.

Even if there was no measurable change in the tone, there are still psychoacoustic reasons why guitar amps sound better played loud.

[David Schwab]

If the guitar volume potentiometers always lose treble frequencies...I wonder whether the potentiometers used in amps lose treble too. If so, then the lower the volume of the amp, the less clear it sounds, and the only way for it to sound right is to play it on full volume - is that so?

As you turn down the volume, you are inserting series resistance after the pickup. This increases the impedance and you lose highs.

You can either use a treble bleed circuit, or an active buffer. Active pickups, and guitars with active buffers do not lose highs when you turn the volume down because the output impedance is low.

This explains why it happens: