Odd value pots

[Superfly76]

Last month I came acrost a website that showed how to use a pot and 2 resistors to make a lower value pot. Alas, I failed to bookmark the page. I'm building a pedal that calls for two 1k pots but the lowest value pots I have are 2k. All I need to do is to wire the two x value resistors from the wiper to terminal 1 and 3. Do any of you know what the formula is for determining the values of the resistors?
Thanks,
Doug

[JimRayden]

Calculations show that this would mess with the taper a bit. Let's say you center the pot. Then you put 1k resistors from the wiper to the side lugs. That looks fine, 500 ohms on both sides, looks like a 1k pot at center. Now turn it fully CW or CCW, now you have 2kpot paralleled with 1k resistor. That would make 666 ohms a whole value, correct me if I'm wrong. That is quite a bit off from the wanted 1k. But you can make compromises, like 1k5 resistors. At the center it would be 600 ohms on both side, on extreme settings, 857. The thing wrong with resistors - the value of the pot changes while you turn the pot. 

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Jimbo

[stm]

Don't give up. Check the Math helpers available at Analog Alchemy http://www.diystompboxes.com/analogalchemy

That'll help you define the resistors and pot.  Be aware that it is mainly usable for POWER DIVIDER applications, i.e. as a voltage divider where the actual value of the pot is not critical. This is typically the case of volume controls.  In a tonestack, I've managed to change the taper somewhat with this method, and according to the simulation, the deviation in the frequency response is acceptable in most cases, especially if you play around with the values. You have to do your own experimentation. YMMV. (I always wanted to say that!)

Now to your particular problem, start placing 1K on each side and see (hear) how it works. If unsatisfied, try with 1k5 or 680 ohms as well. Don't be afraid of using different values on each side also1 (680 and 1k5 or viceversa, for instance).  Of course the final value would be somewhat off the schematic value, but this doesn't mean it will sound worse per se.  Things are not either Black or White! Don't be afraid to experiment and trust your ears more than what's on the paper--it is not the bible!

[Superfly76]

Don't give up. Check the Math helpers available at Analog Alchemy http://www.diystompboxes.com/analogalchemy

Thanks STM ,
The Math Helpers at Analog Alchamy was the site that I came acrost last month but forgot about. The pot in queston will not be used for volume so I think this will be ok. It will control the depth in a tremolo pedal I am building.

[JimRayden]

Don't give up. Check the Math helpers available at Analog Alchemy http://www.diystompboxes.com/analogalchemy

Thanks STM ,
The Math Helpers at Analog Alchamy was the site that I came acrost last month but forgot about. The pot in queston will not be used for volume so I think this will be ok. It will control the depth in a tremolo pedal I am building.

He actually ment that it could be used for vol, as the overall pot resistance isn't critical. But i guess it won't harm the tremolo controlling either.

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Jimbo