hmmm...curiosity with resistors

[korovamilkdud]

So we use normally use .022 or .047uf capacitors for connecting our volume and tone pots right? The higher the value the more bass at (0).

What happens when you use resistors instead to connect the pots? Will the tone knob make the sound brighter when you roll it off? hmmmm.... :dance:

 

[Gr8Scott]

Re: hmmm...curiosity with resistors

IIRC - The higher value cap, the lower the frequency that is trimmed and sent to ground. If you lowered the value of the cap, the trim point for frequencies would be higher and thusly you wouldn't be cutting the frequencies off at the same point. Cap values determine where in the frequency spectrum the cut occurs. Varying the amount of resistance in line with the cap to ground varies how much of the frequencies above the cut line go to ground and are silenced.

If you remove a cap and put in a resistor, you will most likely be cutting the volume of the guitar. Pots are variable resistors.

 

[STRATDELUXER97]

Re: hmmm...curiosity with resistors

So we use normally use .022 or .047uf capacitors for connecting our volume and tone pots right? The higher the value the more bass at (0).

What happens when you use resistors instead to connect the pots? Will the tone knob make the sound brighter when you roll it off? hmmmm.... :dance:

Caps are frequency dependent and in a guitar circuit don't add anything,but rather they shunt highend to ground....I'd say the whole circuit including the caps is "passive"....

A resistor is a current limiter...I'd imagine only negative results if you were to use a resistor in the place of a cap...It is fine to use a 500k resistor across both outside legs of a 1 meg pot however,but the resistor also changes the taper on the pot...

 

[Chaos]

Re: hmmm...curiosity with resistors

A capacitor and resistor in parallel create a band-pass filter. That is, a filter that allows a certain frequencies (band) to pass thought it while blocking all others.

In a guitar tone circuit the resistor is a potentiometer (variable resistor). By changing the resistive value you change the center frequency of the band-pass filter. By changing the capacitor, you change the range the potentiometer has control over.

The output of the band-pass filter is tied to ground, so any frequency that is allowed to pass is grounded and removed from the signal that is fed to your amplifier. A guitar tone control simply grounds a range of frequencies (treble) determined by the capacitor and potentiometer.

Replacing a capacitor with a resistor would do nothing more that put two resistors in parallel (one fixed and one variable)

The total resistance for resistors in parallel is always less than the smallest resistor in parallel. This means that any resistor you add to your potentiometer will decrease the value of the potentiometer (which in turn will reduce your output). Not much reason for doing that unless you want to reduce a 500k pot down to 250k.

For those of you that are interested:
The formula for parallel resistance is Rtotal =1/ (1/R1) + (1/R2) + (1/R3) …

k:

 

[korovamilkdud]

Re: hmmm...curiosity with resistors

Good info guys thanks.