Replacing pots with resistors

[phector2004]

Hi everyone,

Tried digesting RG's "Secret Life of Pots" article, but I'm really out of it after a 5 hour practice MCAT, so I'd appreciate if anyone could double-check my idea 

Now, cranking something up = clockwise turn from above, so if you look at the pot from underneath, it would be a counter-clockwise turn, meaning the full resistance of the pot is below the wiper. Correct?
Well, assuming that's right, I'm still terribly absent-minded for accidentally ordering 24mm pots for a 1590A enclosure, but I feel I can save myself by replacing one or both of my pots by replacing them with a resistor to ground attached to a wire going from my output cap to the jack. Any thoughts?

On a side-note, this is a rangemaster/muff fuzz combo module that i'll be keeping on... would it be DIY blasphemy to remove the volume pots? Gonna try and keep it on the RM, but the enclosure layout is delaying me bigtime

[Taylor]

You'll need to provide a little more information. Pots can be used in different ways, and replacing them with fixed resistors requires knowing how the pot is being used. Could you provide the schem and tell us which pots you're replacing?

If it's just volume pots, you don't need a resistor at all. Normally the signal enters the clockwise lug and exits the wiper, and the counterclockwise lug is grounded. Just take the signal where it would enter the CW lug and connect it to your output jack. It will permanently be at full volume. If you want to lower volume, you'll need 2 resistors, and you'll need to work out the values as you normally would with a voltage divider. Equal resistors give half volume for example.

[phector2004]

http://www.generalguitargadgets.com/diagrams/muffsc.gif
http://www.generalguitargadgets.com/pdf/ggg_geb_npn_sc.pdf

I actually tried sending the output out of the muff fuzz directly from the output cap before I perf-boarded it. There wasn't any output at all. Re-breadboarded it twice, and still nothing. Then I added the volume pot and it worked like a charm. Haven't played with the Rangemaster yet, but its on my breadboard... might keep the pot on that one though.

Any ideas what went wrong with the MF?

Thanks

[Taylor]

No, can't see any reason why that wouldn't work. Must've been an error somewhere in your build.

You can think of a potentiometer as 2 resistors connected together at one end each. The wiper is the point where they meet. As you turn the knob, the resistor on one side becomes larger in value while the other gets smaller, and vice versa turning the other way. To replace the boost knob in the RM you'll need to use 2 resistors. Connect them together, and the other end of one the collector, and the other end of the other to 9v. The joint between the 2 resistors connects to the output cap.

You could also replace these pots with trim pots, which are small but work like regular pots. This would allow you to set them how you like them and then leave them that way inside the box.