"The Secret Life of Pots" help

[nognow]

http://geofex.com/Article_Folders/potsecrets/potscret.htm

I didn't quite understand the following
"Unfortunately there's a gotcha in there. It's true that the voltage division ratio of this rig is arbitrarily close to that of a log taper pot. However, neither the load seen by whatever drives Vin or the source resistance as seen by the input of whatever is connected to Vout is close to what would exist for a real log pot of value R. In fact, the load on Vin varies from 1/(1+1/b)*R up to R. That means that if we're trying to do a log taper with b = 1/4, the load on Vin will be as much as 0.2* R. This may be OK, but you have to keep it in mind.

In general, if you have a voltage source that can drive a load of 1/4 to 1/5 of R and a load on Vout that has an input impedance much higher than that same 1/4 to 1/5 of R, this is a good replacement for an audio or log taper pot."

is simple terms,when I am NOT support to use the "fake taper" trick?

Thanks!

[R.G.]

is simple terms,when I am NOT support to use the "fake taper" trick?

What that quoted section means is:
"There is no way to know whether you're supported  by the "fake taper" until you know what the source impedance driving your pot is and what load impedance you see on the wiper. You have to know those first to know it's going to work as expected. Otherwise, you may get lucky. Or not."

[nognow]

from what I know , pedals have really high input impedence  ,does that mean that the trick should work most often to not?

[R.G.]

from what I know , pedals have really high input impedence  ,does that mean that the trick should work most often to not?

If it's being used as a final volume pot, and the following pedal happens to use the "normal" 1M, and you're using a 100K or lower pot for attenuating, and the circuit you're using it is does nor rely on the pot to do something special in terms of loading or frequency response, yep, most often it will.

[nognow]

is there a way to test it "in the circuit"?
meaning that I'll measure the overall resistance of the pot+resistor "system",and make changes accordingly?

[armdnrdy]

Breadboarding.

I approximated the custom audio taper speed pot in the Mutron Flanger clone that I worked up.

Dino (digi2t) took measurement of the original pot, I did the calculations to get close, then I breadboarded the pot and taper resistors to dial in as close as I could to the original taper.

[R.G.]

Sure. Just hook it up, run the system and see if you like it. Tinker the parts values until you do like it.

But that could be a very long process unless you have some idea where you're going first. Or at least some idea of the ranges of the values you're getting on the inputs and outputs of the "system", that being the pot plus resistor here.

A lot of circuit design math is intended to shorten that process down to only one or two values. But a huge swath of the pedal world consists of people making something then "easter egging" parts in and out until they like the sound.