Dumb pot question for a simple mod

I see the thinking and I think it would work, but maybe that middle pin of the pot being connected might make a difference. (I've learned never to count on my reasoning when it comes to logic in electronics :))

If it does though, you only need to use a double throw switch instead of a single throw and have it select either 'middle pin' or 'direct from pickup', ie:

From pickup ------
|
|
-----/////------ Ground
| |
| switch |
--o o---|

To jack


...instead of...

From pickup ------
|
|
-----/////------ Ground
| |
| / |
--o o----|
switch |
|
|
To jack


If it was me, I'd just try it during the mod and see which works best for me. It's not a project too big to experiment with :)

As C&S infers, this won't work as expected if the pot is set near '0'. The double-throw switch is the better solution.

Thanks, I didn't know if it would work because I thought the signal might feedback through the pot instead of going out. That is why it won't work correct?

Here comes some electrical theory questions now as I'm intrigued. Just fare warning

I don't have a strong understanding of pots even though I've looked at them countless times. I know the wiper moves up and down causing the resistance to vary, but do you have to connect all three spots of the pot? Is it possible to leave one of the ends unconnected so that the schematic looks like this or does the pot work (for volume control purposes) by using the wiper to ground voltage to drive/control the volume level (the larger Vwg is, the larger the ouput voltage)?.

Vwg = Voltage from wiper to ground

Thanks again.

With a little practice, on many guitars you can turn the knob with your pinky while you're playing. Skillful users of that technique can get some REALLY cool sounds that way.

With a little practice, on many guitars you can turn the knob with your pinky while you're playing. Skillful users of that technique can get some REALLY cool sounds that way."Volume swells" are cool. I've got a Phil Keaggy DVD with him doing some. Excellent. 8)
Okay, two of those "lugs" (terminals) on the pot, usually the outer two, just go around the wiper. (Full resistance of the pot.) Either of those, with the center lug, will give you the variable resistance. Which one you use will determine whether the resistance increases as the knob is turned clockwise or CCW. (I think that's "anti-clockwise" to our friends in the UK. :wink: )
EDIT: I was going to call your idea for bypassing the volume control a "blow switch," which I've also seen used for a switch that bypasses the tone control. I guess the original "blow switch" idea was in the Danelectro U3 guitar, and made to "override" any pickup setting, putting all three singlecoils in series. Now that would give you some screaming lead sounds.
http://www.deaf-eddie.net/pushpull/pushpull.html
What have you got for pickups in that one you're looking to mod?

For more detail on Doug's suggestion of using a "slope resistor," see R.G. Keen's article The Secret Life of Pots.

For more detail on Doug's suggestion of using a "slope resistor," see R.G. Keen's article The Secret Life of Pots.I knew I'd seen that information someplace. Thanks for reminding me it was R.G. Keen.
Here's another one: http://www.ultimateguitargear.com/ken_fischer_chapter2_1.htm

Thanks for all the replies fellas.

First my pot question: I understand the rotating wiper and the ends would make 500k ohms, but if the resistor is just varying and my signal isn't dependent on one of the ends touching ground, then why wouldn't the 2nd picture I put up work to bypass the volume control?

What have you got for pickups in that one you're looking to mod?

Just cruddy standard ones that came with my 70 dollar squier bullet. I'm actually interested in electronics more than guitar, but I enjoy playing guitar so to me it just makes sense to use electric guitars/amps in electronic applications.

I had some other ideas to try, but I need money and another (thicker) beater guitar before I can even think about them. The main one is installing a microcontroller that would control an led sequence of somesort, and then tinkering with it more to try and get it to respond to changing volumes or frequencies(notes). Just dumb stuff like this that have no real actual value.

What have you got for pickups in that one you're looking to mod?
Just cruddy standard ones that came with my 70 dollar squier bullet.Okay; I meant singlecoils or humbuckers. I should've been clearer with the question.
Yup, got a Squier "Bullet Special" that lives here. It's in Double Drop D right now, so I can work on Neil Young's "Cinnamon Girl." The Bullet Special is the one with a single (bridge) humbucker and no tone control. I've got a DiMarzio X2N® to go in it some day.
I'm actually interested in electronics more than guitar, but I enjoy playing guitar so to me it just makes sense to use electric guitars/amps in electronic applications.Absolutely. Being able to combine two of your interests like that is great.
I had some other ideas to try, but I need money and another (thicker) beater guitar before I can even think about them. The main one is installing a microcontroller that would control an led sequence of somesort, and then tinkering with it more to try and get it to respond to changing volumes or frequencies(notes). Just dumb stuff like this that have no real actual value.Yeah, but those ideas are keeping you "off the streets and out of mischief." (We hope.) :lol:
Speaking of doing things with LEDs, I'd almost bet there was a time when somebody said this had "no real actual value," but I bet there are users out there who'd disagree with that: http://www.fretlight.com
plz im a noobAll of us were, at one time or another. Come to think of it, in a lot of ways, I still am! :wink:

OK, I think I have it straight in my head now (it's been a long time - it was only a naggoing doubt but I had this in my head somewhere :))

Don't think of a pot as a variable resistor, think of it as a potentiometer. A variable resisistor gives you a resistance somewhere between none at all and 500k (in this case), and only has two contacts. A pot gives you a potential (voltage) somewhere between whatever is at one contact and whatever is at the other, and has three contacts. People use the terms interchangably because a pot can be wired to function as a variable resistor by just using two of the three contacts, but it is actually two variable resistors joined in the middle.

With your single throw switch, what you're doing is shorting out one of those variable resistors inside the pot, but not both. That means you're switching between a pot (ie, two variable resistors) and one variable resistor, which is not what you want to do. You want to bypass the whole pot, not just half of it. That's because when switched on:

- At full volume it would do as you expect, as the resistance between the signal and ground is enough to stop any signal passing (so far so good).

- At zero volume the signal and the ground are connected directly to each other and you therefore get no signal at the jack (so it's not a volume bypass any more, but still as you'd expect a volume control to work).

- In between you're using a variable resistor instead of a potentiometer, and you'll get a different relationship between position to volume (not sure off the top of my head - I think it'll give you all the volume control between about 0 and 2 but don't quote me :))

Wiring it as I posted will bypass the pot completely when switched, effectively making it just a normal resistor between signal and ground, ie, exactly what we've got at full volume. When switched off, the pot will work exactly as if you'd never touched it.

Hope that helps, but i enjoyed figuring that out anyway - it blew a few cobwebs out from between my ears :mrgreen:
Speaking of doing things with LEDs, I'd almost bet there was a time when somebody said this had "no real actual value," but I bet there are users out there who'd disagree with that: http://www.fretlight.com Wow, do those guys ever need a copywriter :shock: Nice idea though - I think I saw Mark Knopfler play one on Tomorrow's World once...

Hope that helps, but i enjoyed figuring that out anyway - it blew a few cobwebs out from between my ears :mrgreen: Outstanding. I don't think I could have sussed out all of that.
Even if what you wrote isn't 100% correct (and I'm no one to say, either way), you sure wrote it out well.
Speaking of doing things with LEDs, I'd almost bet there was a time when somebody said this had "no real actual value," but I bet there are users out there who'd disagree with that: http://www.fretlight.com Wow, do those guys ever need a copywriter :shock: Nice idea though - I think I saw Mark Knopfler play one on Tomorrow's World once...I just had a funny idea of the computer it was connected to, trying to keep up with Knopfler. :lol:

Thanks for the help guys. Went and bought a 2 way SPDT toggle and got it installed and working properly for the most part.

The pot was in bad shape with solder all over it (I don't think I'm a fan of this for ground bus use, but whoever owned it b4 me was and left solder everywhere) so I plan on replacing when I get the part in (no 500k pots at either the guitar shops in town or RadioShack). When I do, I will do a complete rewire as it has shady wiring all over the place.

Thanks all :).

And by the way, my guitar is a bullet special. I love its lightweight because I am a very small guy.