Replacing Pots with resistors, am I doing it right?

[Chris!]

Hello folks,

story first, then a more detailed question:
I want to build a "just tone knob" tubescreamer-like pedal for my board since it's the only control i fiddle with during my bands live set. Hence I'm going to build myself a Maxon OD 808 without the level and drive knobs.
I want to use this layout:


Question is: how do I replace the pot's correctly?
For the drive it seems pretty clear, connect the two holes with a 500k resistor. I usually run it at the lowest setting.Is there a way to decrease the amount of distortion I get at minimum setting without messing with the rest of the circuit too much?

As far as the level knob goes, I always run it maxed. how do I go about this? A resistor between the holes where volume 2 and 3 would  usually connect to the pot and a bridge between level 2 and 1?

I appreciate the help a lot and thanks for reading.
Cheers
Chris

[induction]

For the Drive pot, more resistance here equals more gain, so replace the pot with a jumper. Using a 500k resistor will put you at max gain. To reduce gain even more, reduce the 51k resistor. Maybe try a 50k trim pot wired as a VR and dial it where you want it. Then either leave it there, or take it out, measure where you ended up with a DMM and replace it with a fixed resistor.

As for the volume, replace the pot with a 100k resistor and then jumper where Level 2 used to be to where Level 3 used to be. Connecting 1 and 2 would put you at min volume, giving you pure dry signal.

[induction]

Sorry, I didn't see the cut underneath the 100k resistor. The last sentence should say, 'Connecting 1 and 2 would put you at min volume, giving you no signal.'

The rest should be correct.

[Chris!]

I always thought turning a pot fully clockwise equals no resistance, hence fully counter clockwise maxed resistance? Correct me if I'm wrong though.

[GoranP]

It depends on how it's wired. That's why you often see "swap 1 and 3" on any new build thread here. Full turn either gives you zero (or near zero) resistance or full nominal resistance, it only depends on from which side you look at it.

[Chris!]

Sorry guys, posted the wrong layout.
Forgot that I built a regular 808 instead of the reissue



Should be pretty much the same though, right?

[induction]

Goran's right.  When a pot is wired as a voltage divider (like the 'Level' or 'Balance' control in this circuit) swapping connections 1 and 3 reverses the pot behavior.  

When it's wired as a variable resistor (like the 'Gain' or 'Overdrive' controls here), the direction of increasing resistance depends on which lugs are tied together (or which one is unused).  If lugs 1 and 2 are tied together (or 1 is unused) increasing the pot setting decreases the resistance.  If lugs 2 and 3 are tied together (or 3 is unused) increasing the pot setting increases the resistance.  The latter is the case in this layout.

This is convenient because it allows designers to create intuitive controls.  You'd expect a pot labeled 'volume' to behave differently than one labeled 'silence'. The Timmy's bass and treble cut controls come to mind.

In any case, my advice is the same for either layout.  Proceed with confidence.