#1
Can anyone explain to me electronically how a tone knob works?
MG Free At Last
#2
It controls a tube that sets a threshold for certain frequencies. When fully open (rolled up to ten) it lets all frequencies, high and low end, to operate pretty much the same. When rolled off, it takes of the high end and seems to boost the low end. Sort of like a wah.
#3
^Incorrect.

The standard guitar type tone knob works like this:
A capacitor is used as a treble bypass coming off the main wiring unit. Then a pot shunts this treble to ground in varying amounts.

Hard to explain.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#4
yeah that sounds about right, but i'll put it in lehmens(sp?) terms. The signal goes into the pot, and an amount controlled by the knob goes to the capacitor(cap) with gets rid of some of the treble (depending on the value of the cap, higher value, more treble got rid of).
hope i helped
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#5
Quote by northy
yeah that sounds about right, but i'll put it in lehmens(sp?) terms. The signal goes into the pot, and an amount controlled by the knob goes to the capacitor(cap) with gets rid of some of the treble (depending on the value of the cap, higher value, more treble got rid of).
hope i helped


layman's


So how about you guys explains how/why it also adds bass when you roll down the tone?
#6
TPQ is right in that its hard to explain. ill give it a shot, but you might not undestand all of it.

to start, we have to look at a guitar signal. when you pluck a string, it vibrates the magnetic field of the pickups. this in turn creates a current in the coil around the magnets through something called magnetic induction. because the string is vibrating the magnetic field at a spefic frequency (that of the note) we get an alternating current of that frequency in the coil. this AC current is then sent to the tone knob.

ok, so now we have our AC current at the tone knob. it is important that this current is AC, it wont work if its a DC current. ok, so now we look at the tone knob. here we have a potentiometer (acting as a resistor) in series with a capacitor. this gives an RC circuit. now, when an alternating current goes through an RC circuit it acts as a low bypass filter. that means it bypasses all frequencies below a certain point. the graph of an RC circuit is as follows:

ok, so then as we turn the potentiometer, we add a greater resistance to our RC circuit. this changes our target frequency. so when the knob is turned to 0, we have a lower target frequency. so this means that everything above this frequency is going to be rolled off. when the knob is on 10, we have a high target frequency so very little is rolled off.

i can go into a bit more depth if you want, but i would guess that that explanation is probably good enough for now.

FUN FACT: you can make a high pass filter with a resistor (or pot) and an inductor.
#7
Quote by jof1029

FUN FACT: you can make a high pass filter with a resistor (or pot) and an inductor.


Yay!


So, can you explain why bass is added? Is just our hearing that is (once again) 'hearing' things?
#8
It depends on the values of the capacitor. Low values in the pFs and low uFs (ex: .01uF) are very much more trebly. Higher values in the mid uFs (ex: .22uF) allow much more bass.

The capacitor is adding bass, and at 10, the guitar is stock.

It depends on which side (lug 1 or lug 3) you put the capacitor to tell if 10 is going to be the most bassy, or 10 is going to be the most trebly.
#10
it doesnt add any bass at all, it just sounds that way. its a passive circuit so you can only cut frequencies, you cant boost them. the bass just sounds louder because there is less treble.