Pot values

Pedrogas

Pedrogas

New member
Hey guys, I read somewhere having a pair of 500k volume + 500 k tone is the same as having a single 250k volume, is this right?
I'm planning to remove the tone of my Jazz neck humbucker, since I never use it and I find it muddy sometimes with overdrive.
If I do this, does it means I'll have the equivalent of 1M volume + 1M tone in the Jazz neck?
Thanks in advance.
 
Definitely not. While, on the surface, it might seem like it's two 500k resistors in parallel, the tone pot impedance is frequency dependent, because of the cap. It's not the same.

Well, wait a sec. I read that too fast. You said a "pair" of 500k's. I believe that would be similar if both pups were on at the same time. But not the same when only one pup was engaged.
 
So basically, strats that have
Volume - 3 pickups
Tone - Middle
Tone - Neck
The bridge Pickup sounds the same as 500k volume + 500k tone ?
 
Ok, if I understand this correctly, a 500k volume pot with a 500k tone pot is not the same as a 250k volume pot.
 
Pedrogas said:
Hey guys, I read somewhere having a pair of 500k volume + 500 k tone is the same as having a single 250k volume, is this right?
I'm planning to remove the tone of my Jazz neck humbucker, since I never use it and I find it muddy sometimes with overdrive.
If I do this, does it means I'll have the equivalent of 1M volume + 1M tone in the Jazz neck?
Thanks in advance.
Click to expand...

You find the Jazz muddy?!!
 
I found this

Does the number of control pots used affect the sound?
Yes: Since the load on the pickups is determined by the total parallel resistance of all pots that are being used at a time, using fewer pots will reduce the overall load and give a slightly brighter sound. Also, connecting more pots is the same as using lower value pots, two 500K pots will loose or "bleed" the same amount of treble frequencies as one 250K pot. To lessen the effect, switching should be designed (when possible ) to remove pots from the circuit when the related pickup is not selected. An example of this is the Les Paul: bridge controls are out of the circuit when in the selector is in the neck position and the neck controls are out of the circuit when the selector is in the bridge position.

https://guitarelectronics.com/guitar-wiring-faqs/

Now I'm confused...
 
That is partially true. The thing is, the 500k is in series with a cap. So the pickup "sees" 500k at very high frequencies, and then that load gradually increases to infinity as the frequency drops. The slope of that drop depends on the value of the cap. The math gets complicated.
 
If you use a no load tone pot (or a switch or something), you can hear the difference between resistance and capacitance in real time. With the tone pot on 10, it's out of the circuit and you only hear the resistance from the volume pot. It's a little more top end edgy. Now turn the tone down to 9.5 where it engages. There's a very subtle difference it sounds slightly more muted and supple. Now alternate between turning only the volume pot down or only the tone pot down and the effect is exaggerated. Turning the volume pot down to where there's a lower resistance to ground, the entire signal is dampened. Turning the tone pot down, only the highs (and mids) are cut above the cap's cutoff.
 
with the usual cap values (10n to 22n or higher) 500k volume + 500k tone is the same as one 250k volume + No tone.
Only if you use small tone capacitor values there is a difference!

the lower frequencies are not damped by the lower pot val and for the relevant frequencies in the resonance range of the pickup the cap is more or less a short. So the highs see 250k with both 500k pots on "10".

i also ran a spice simulation on this.

the cutoff frequency of a 8.5k wind and a 22nF cap is around 851Hz. So at the Resonance Peak of the PU the Tone Cap is more or less a short -> So 2x 500k in parallel -> 250k

Pedrogas said:
Hey guys, I read somewhere having a pair of 500k volume + 500 k tone is the same as having a single 250k volume, is this right?
Click to expand...
So: yes, more or less
if anything 250k vol no tone should be brighter because the lows get attenuated a wee more (doubt you can hear that) but the height of the resonant peak is the same
 
Last edited:
ToneFiddler said:
with the usual cap values (10n to 22n or higher) 500k volume + 500k tone is the same as one 250k volume + No tone.
Only if you use small tone capacitor values there is a difference!

the lower frequencies are not damped by the lower pot val and for the relevant frequencies in the resonance range of the pickup the cap is more or less a short. So the highs see 250k with both 500k pots on "10".

i also ran a spice simulation on this.

the cutoff frequency of a 8.5k wind and a 22nF cap is around 851Hz. So at the Resonance Peak of the PU the Tone Cap is more or less a short -> So 2x 500k in parallel -> 250k
Click to expand...



I use 22 in SC, P90's and HB...
 
you should be fine with 22n...
Pedrogas said:
If I do this, does it means I'll have the equivalent of 1M volume + 1M tone in the Jazz neck?
Click to expand...
that'S also a correct conclusion by the way. 500k vol + No tone equals 1Meg vol. + 1Meg tone.

the jazz neck PU is not muddy, but it can get boomy in some guitars. lower the height on the wound string side.
if that's not enough, maybe add a series cap to make a highpass.
 
ToneFiddler said:
you should be fine with 22n...

that'S also a correct conclusion by the way. 500k vol + No tone equals 1Meg vol. + 1Meg tone.

the jazz neck PU is not muddy, but it can get boomy in some guitars. lower the height on the wound string side.
if that's not enough, maybe add a series cap to make a highpass.
Click to expand...

Thanks a lot, pal.
For me the neck pickup is never bright enough!
 
For volume pots, two 500k pots in parallel is 250k (and two 250k pots is 125k).

As stated earlier, tone controls change impedance depending on the frequency and where the pot is set.


Sent from my iPhone using Tapatalk
 
When the volume is at maximum they will sound the same, like others have said here. However when you roll down the volume, the 250k will sound brighter because it has less loss and less prone to high frequency loss due to the cable capacitance.

If using 500k volume control, I always add a treble bleed circuit to restore the high frequencies. It may not be absolutely necessary with a warm humbucker style guitar, but IMO treble bleed is essential if you want a guitar with split-coil tones or Stratocaster style sound
 
Teleplayer said:
Sorry my post wasn't clear. In the context of post #1, the OP asked about the difference between a single 250k volume vs a pair of 500k volume + 500k tone pots.
Click to expand...

Well, even with that understanding of your post, a single 250k pot will not sound brighter than two 500k pots unless the tone pot of the two-pot scheme is turned down considerably. But that's what a tone pot does with any value pot.

But you need to read Artie's post, there is some complex valuation going on as you turn down that tone pot. You can't just make a blanket statement like that because it simply is not true (except under certain conditions).
 
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