Mixing 250K & 500K Pots

Gris

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I put a 500K vol pot in my Tele w miniHB in neck & trad SC in bridge. Left the 250K tone pot. Really made the PUs come alive in a good way. Seems like the tone control is more drastic roll off now, but that’s kinda good given the bridge PU’s new brightness. Not sure what value cap I wired in there, was one from before. I did the ‘50s LP wiring.
 

schmee

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Yeah, the interaction is not as simple as the way some explain using 250k vs 500k pots.
 

Willie Johnson

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I have my single p90 Esquire thing like that--1 Meg volume, 500k (iirc) tone. Sounds great with the tone rolled off 50% or wide open.
 

bebopbrain

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Pet peeve: tone pots should be 1M. You get more sounds without altering or losing the (darker) sounds you had with the smaller pot.

There isn't much difference between a 1M tone pot and a 250K; turn the 1M down slightly and the resistance is 250K. If you don't like the light load 1M setting, you can always, like Jeff Beck, turn the knob.
 

Phrygian77

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in the Thinline I got recently, I did a 500k volume with a 250k tone and a 470k load resistor on the bridge pickup. It has a Lollar Novel 90 neck and a Lollar J Street bridge. It originally had a 250k volume, which I thought made the neck pickup a touch dark. The 500k helped to brighten it up just enough.

Now, I wish I could find 'dish' back 30% taper (J taper) CTS pots in 500k with a solid shaft. Those dish back pots are hard to find these days.
 

wabashslim

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You can always put a resistor in series with the tone pot to prevent it from being turned down all the way. I think I used a 1K but you can try any value & work from there.
 

KokoTele

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The combination of 250k/.047uf and 500k/.022uf produce very similar results. Not worth changing just because you changed the volume pot.
 
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NoTeleBob

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You can always put a resistor in series with the tone pot to prevent it from being turned down all the way. I think I used a 1K but you can try any value & work from there.

Turn the tone pot to where you'd like the minimum to be. Measure the resistance with a DVM. There's your value to set as the minimum with a fixed resistor.
 

SixStringSlinger

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Turn the tone pot to where you'd like the minimum to be. Measure the resistance with a DVM. There's your value to set as the minimum with a fixed resistor.

Does this make the tone control's effect "stop" at a certain point (that is, making it not change as you turn from, say, 0-5), or is the whole sweep of the knob effective but more gradual with the set minimum as the lowest point?
 

NoTeleBob

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Does this make the tone control's effect "stop" at a certain point (that is, making it not change as you turn from, say, 0-5), or is the whole sweep of the knob effective but more gradual with the set minimum as the lowest point?


The capacitor on the tone control basically hangs off the hot line to the output jack. It lets high frequencies (only) go to ground through the capacitor (effectively disappear).

The tone pot is wired so that it is between the hot signal line and the capacitor. When your tone pot is on 10 (max treble), the pot is at maximum resistance i.e. it's like putting a 500K resistor between the capacitor and ground. It's preventing (mostly) any signal from getting to the cap and then to ground. On the other end, when the tone pot is at 0, it's at minimum resistance (0) and letting almost all the signal get to the cap and to ground...letting all your treble go to ground.

If you put a fixed resistor into the line, it's like the pot is set part way. It's blocking some of the signal from getting to the capacitor. Because of that, you can't make the guitar as dark as you could without it there.

If you dial the pot down to the darkest setting you ever want, and measure the setting on the pot at that point, you could simply then add a resistor of that value in series between the tone pots hot lead and the pot, or alternatively, in series with the cap and ground. That way the control never goes below that minimum resistance value.

Example: I have a 250K tone pot. I add a 100K resistor in series between the cap and ground. The pot now adjusts from (effectively) 350K to 100K. My guitar won't get as dark because I always have at least 100K of resistance in the line to the capacitor.

You might wonder... but now the pot adjusts from 100K to 350K, does the 350K (vs. original 250K) resistance matter? The answer is "sort of". It means that at the max setting (350K) even more of the signal is being blocked. Theoretically, your guitar might be brighter on 10 than it was before. But on a practical basis, the 250K tone control was already blocking most of the signal. Also, having a little more brightness on tap is never a bad thing. You can set the control to 9, instead of 10, if you think it's too bright. Note that humbucker guitars typically use 500K tone controls to brighten them up a little.
 




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