October 21, 2009

Pots, Wafers, Wipers, Shafts, Dimples

Guitar Potentiometers Electronics, Video 191

How do potentiometers actually work, and how are they built? In preparation for my tutorial on how to make a no-load tone pot, I dissected a couple pots (the same Bourns and CTS pots I’ve been looking at in my other videos). In this video, I explore the details of pot construction and how they actually work.

Correction: in the video at 6:25, I said that the narrow part of the wafer had less resistance than the wider part. That’s backwards! For the same length, a thinner wire has more resistance than a thicker wire. Similarly, at 4:37, when I said “more stuff to go through, more resistance”, it would have been clearer to say “longer length, more resistance”.

191 Comments

MathieuAllain
October 4, 2011 @ 4:44 pm

THANK YOU!! 🙂 ) )

Reply
John
October 4, 2011 @ 4:55 pm

@MRacer001 – no, this is a standard pot with a resistive track printed on a wafer and a wiper that rides on the arc of that track, used in passive analog electronics. A “continuous pot” or rotary encoder is totally different, typically used in digital applications, requiring a small microprocessor, etc.

Reply
John
October 4, 2011 @ 4:55 pm

@MRacer001 – no, this is a standard pot with a resistive track printed on a wafer and a wiper that rides on the arc of that track, used in passive analog electronics. A “continuous pot” or rotary encoder is totally different, typically used in digital applications, requiring a small microprocessor, etc.

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dizzybot
October 8, 2011 @ 11:44 am

wow, i was looking for a good potentiometer video, and this was so well made thanks! how come peoplie cant make a detailed video on electronics, more like this!!

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SamwiseGUITAR
October 9, 2011 @ 4:15 pm

Thank you for this video! Which pot do you prefer? Is one smoother than the other by feel and taper? Thanks so much!

All The Best,
Sam

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- John
  October 9, 2011 @ 8:54 pm
  
  @SamwiseGUITAR – it’s really personal preference- you need to find one that works for you! I’ve used the CTS EP-0086 in a number of projects and liked them. I use 16mm alphas in most of my pedal projects.
  
  Reply
  - SamwiseGUITAR
    October 9, 2011 @ 10:29 pm
    
    @johnplanetz Thank you! What about inside guitars? Thanks again!
    
    Reply
    - John
      October 14, 2011 @ 4:15 pm
      
      @SamwiseGUITAR – sorry my first reply wasn’t clear. I meant to say, I’ve used the CTS EP-0086 for guitar tone/volume pots and liked them. I use 16mm alphas in most of my pedal projects.
      
      Reply
rcmoot
October 28, 2011 @ 6:45 am

it is so nice to see you are informing us on these simple things

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bedofrazorsqwerty
December 2, 2011 @ 5:22 pm

Am I a nerd for knowing all of this and watching it anyways for fun? How about on a Friday night? By myself?

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- John
  December 2, 2011 @ 5:52 pm
  
  @bedofrazorsqwerty – I’m honored 🙂
  
  Reply
- Gadsonyc
  December 25, 2011 @ 9:05 pm
  
  @bedofrazorsqwerty On christmas eve too! 😀
  
  Reply
- Gadsonyc
  December 25, 2011 @ 9:06 pm
  
  @bedofrazorsqwerty On christmas eve too! 😀
  
  Reply
Naregnemyes
December 2, 2011 @ 6:34 pm

Message sent. I don’t know how effective increasing thickness of the strip would be, since the signal should just be able to take the shortest path right? If changing the materials/conductivity along the strip is too expensive, I thought of a cheap way to approximate a log.

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- John
  December 6, 2011 @ 6:15 pm
  
  @Naregnemyes – resistance is a little counter intuitive. I’m sorry I didn’t say it clearly enough in the video at 4:36 when I said “more stuff to go through = more resistance” (hence my popup annotation bubbles). A fatter wire has less resistance than a thinner wire, but a longer wire has more resistance than a shorter wire. Quoted from wiki: “An object of uniform cross section has a resistance proportional to its resistivity and length and inversely proportional to its cross-sectional area”
  
  Reply
  - Naregnemyes
    December 6, 2011 @ 6:20 pm
    
    @johnplanetz Right, i figured out later that i misunderstood also. but the real question is why is it expensive to create a log pattern? I don’t see what would be so costly about laying a track that tapers from thick to narrow or doing a pattern like the one I messaged you.
    
    Reply
    - John
      December 6, 2011 @ 6:23 pm
      
      @Naregnemyes – I’m not sure- I presume it has something to do with the way the track is is manufactured onto the wafer.
      
      Reply
  - primitiveheadbanger
    March 16, 2012 @ 9:55 am
    
    @johnplanetz I use Duncan’s lw-hmet active humbucker. It uses two 9v’s and has no clean what so ever, which is fine for me. The problem I have is that it clips certain pedals really bad. Using the volume knob works with some but not with others. I also don’t like the response I get when lowering the volume pot. Would putting a resistor before the output help?
    
    Reply
    - John
      March 23, 2012 @ 10:12 am
      
      @primitiveheadbanger – In order to reduce the signal level properly, you’d use a voltage divider with one side to ground, which will give the same effect as lowering the volume pot. In any case, you can very easily experiment with this to see what happens: Use alligator leads and a couple open jacks- plug the guitar into 1st jack, then connect 1st jack to 2nd jack using alligator leads and adding any other circuitry you want there. Then plug a cable from the second jack to the amp.
      
      Reply
      - primitiveheadbanger
        March 23, 2012 @ 10:50 am
        
        I hooked up a volume pot in a box with 1/4 jacks like a pedal with a in & out so to speak. kept my guitar volume on full and lowered the volume on the box. It worked??? I still have the same feel when playing without the clip. I also don’t loose the “thump” I would lose with lowering the volume pot on the guitar.
        
        Reply
Gadsonyc
December 25, 2011 @ 8:58 pm

there is no videos like this in spanish D: well… lets improve my english!

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eduardoo1234
December 27, 2011 @ 10:30 am

where could i buy these ?

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- John
  January 1, 2012 @ 8:42 pm
  
  @eduardoo1234 – try Mouser, or any number of online guitar parts resources. I have some links at my blog at planetz.
  
  Reply
- caulinrocker1
  January 7, 2012 @ 7:37 am
  
  @eduardoo1234 guitarelectronicsDOT com has all of these and more and offer other resistance and taper options on all of them
  
  Reply
halfcabdisaster7
January 10, 2012 @ 7:35 pm

Thanks for the video, pots make a lot more sense now.

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ethanstephenson
January 15, 2012 @ 1:04 am

hey, im trying to hook up an amp to my home surround sound, it has up to 180W going to the sub and i have spliced into that to make a (pre-amp) for my new 3000w (350Wx2ch) amp but i dont want to fry the inputs with the 180w input, so im trying to install a “pot” to turn down the input into the new amp. im wandering if there is a formula to tell me how many ohm pot i need to splice in? any clue?? i dont even know it this will work. any hints?

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ChowZeb
January 16, 2012 @ 9:00 am

Good Engineering Information!

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UnluckyFett
January 19, 2012 @ 7:39 am

Thanks, Ive know how they work but your video and explanations really make it clearer in my head on how to wire pots to do different thing

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Azreal677
March 12, 2012 @ 5:05 pm

Really cool video man. Thorough and simple.

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gwmerr
March 15, 2012 @ 7:35 pm

Natural teacher at work here. I came here knowing what a potentiometer does ….always wondered the what & how? In ten minutes I learned so much targeted information! Wow, thank you, johnplanetz

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peavelSD
March 19, 2012 @ 10:13 am

hello, i want to say that i really appreciate your effort you put into these videos, these are really helpful!

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peavelSD
March 19, 2012 @ 10:15 am

i have one little problem, maybe you would know what may be wrong..? i’ve been replacing a pot into pushpull – at first i put it in the tone position, then changed the vol and put back the original tone pot, so now the vol is the pushpull and the old tone pot, but when there is a sound and i turn the tone knob i get a noise, which is absent when turning it with no signal. do you think that i damaged the tone pot when soldering? or there may be other problem?

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Socioistic
March 26, 2012 @ 10:47 pm

I have been told that linear pots are not always labeled “B”, and logs aren’t always labeled “A”, as there is no industry standard for which should be which, have you found this to be true?

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- John
  March 29, 2012 @ 5:47 pm
  
  It’s true that sometimes pots aren’t labelled well. I’ve also seen some that say “A” but measure closer to linear. (These were older pots, or those preinstalled on guitars, etc. However, when I buy Alpha/CTS/Bourns pots, I’ve always received what I ordered, and they’ve been clearly labelled…
  
  Reply
  - REX05011
    April 7, 2012 @ 12:39 pm
    
    where can I get a nut for the shaft beacuase I lost mine replacing the pots
    
    Reply
    - John
      April 8, 2012 @ 9:38 pm
      
      You can find typical nuts for guitar pots at stewmac (search “mounting nuts”), or guitarnucleus. Or take some measurements, and find anything you need at mouser.
      
      Reply
      - REX05011
        April 9, 2012 @ 1:48 pm
        
        Thank you a lot I’m fixing up an old ibanez blazer bass and i really need those nuts and washers for it .
        
        Reply
TheeAldeen
April 1, 2012 @ 1:43 am

Great Video – mods on my Channel for you guys!!

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MrSzpatha
April 1, 2012 @ 6:07 pm

Great video, thanks for sharing!

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peavelSD
April 3, 2012 @ 12:15 pm

If i consider the idea in 4.43, can i use a pot as a balance between the pickups? would it work?

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- John
  April 8, 2012 @ 9:05 pm
  
  Since a blend/balance pot mixes two different signals, you need a dual-gang pot. It’s essentially two independent potentiometers stacked on top of each other, controlled by the same shaft.
  
  Reply
oklatex1948
April 4, 2012 @ 10:21 pm

John, I am really pleased to have found your videos. I’ve built a couple of guitars; but, always find myself wondering about the “hype” when it comes to pickups and electronics. I believe watching your videos will teach me to make the correct decisions. In the meantime, while I’m learning, I have a 1988 G & L Invader H-S-S that seems to be crackling a little. Any suggestions on what to replace and a good source for the parts? I would keep the original sound; but, if I can gain some tone???

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- John
  April 8, 2012 @ 9:09 pm
  
  Best thing I could recommend is first take pics and diagram the current circuit. Then disassemble it. Test each component in isolation using alligator leads. E.g. test pickup to jack, then pickup thru volume to jack, then add the tone pot, etc. You’ll find the culprit for your noise, and also be able to experiment with subtle changes like tone caps, etc.
  Parts sources: stewmac, guitarpartsresource, guitarelectronics, or more general electronics stores like mouser and digikey.
  Have fun!
  
  Reply
robertmessore
April 9, 2012 @ 9:49 pm

Thanks for sharing your gift for teaching!

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gaiors
April 15, 2012 @ 1:03 pm

Thanks for sharing that!

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SIRONEDRAGON
April 22, 2012 @ 4:52 pm

Great information John : )

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gregnotes
May 2, 2012 @ 3:34 am

What model multimeter is that? I love all your vids, watching them on my Droid makes it hard to read the multimeter’s model and make lol.

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- John
  May 3, 2012 @ 10:59 pm
  
  It’s a Mastech MS8229. I’ve seen the same DMM under other brand names, like at Harbor Freight, etc
  
  Reply
80amnesia
May 6, 2012 @ 2:05 am

is this related to smoking pot??

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Larry
May 21, 2012 @ 4:09 pm

Hi. Is there a way to lengthen the legs on a 50KAx2 ALPs pot? I have a problem replacing this pot where the MFG. (A/D/S/ had custom pots made by alps for there C1500 Subwoofer Control Unit, vin.1986. I broke the knob off the pot (another story)along with the shaft before the nut thread. There is a white plastic material in side the shaft which turns the wiper etc. I got a replacement pot from China (only one that had it)on ebay. It is stamped Alps Japan and every thing lines up excepting for the length of the legs. Too short 1/8″+. to penetrate the circut board I need to lengthen. Thanks, Larry PS. The replacement pot does not measure as accurate as the original.

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Sean Path
May 26, 2012 @ 4:12 am

Great videos. One Question: I have a spector bass and i noticed that the knobs were like easy or loosed… so i tighten them to the pot, but i think i may did it too hard and, when play the bass, i notice that it loosed so much volume, i don’t know if it has something to do with the tighten of the pots or what could be. I removed the knobs and one pot was like too crashed by the tension and it broke but it’s still working, i want my bass loud again 🙁 what can i do? thanks

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fdre3wsd
June 6, 2012 @ 8:58 pm

excellent teaching, dude

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Jason Sweet
July 9, 2012 @ 9:37 pm

how do you crossfade between 2 sources with a potentiometer?

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- John
  July 10, 2012 @ 9:32 am
  
  You can use a dual-gang pot (that’s two pots stacked on top of each other, controlled by the same actuator/knob). Use them like two volume controls, one for each signal, wired opposite from each other: wire your first signal to one side of the first pot, and your second signal to the OTHER side of the second pot, and mix the two outputs together. See some circuit examples for balance controls at Rod Elliott’s article “Beginners’ Guide to Pots”
  
  Reply
AxelTiger
July 10, 2012 @ 3:19 am

in a nutshell ‘a pot is a variable resistor’? 🙂

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- John
  July 10, 2012 @ 9:38 am
  
  That’s an oversimplification. You’ve got three lugs there. If you just look at the resistance between the center lug and one of the side lugs, then you can call it a variable resistor. But then you’ve got that other side lug over there. And it’s a variable resistor too, controlled by the same pot shaft, but working in the opposite direction.
  
  Reply
E5Bobby
July 22, 2012 @ 1:55 pm

I thoroughly enjoyed this video John. Thank you for making it. It was VERY well done. I’ve got a rheostat on a ceiling fan that only has two lugs. I think it’s bad because the fan spins very slowly across the whole range of the rheostat. It’s soldered into place so I’m going to take it out of the fan (circuit) and test it with my VOM. If I can tell it’s bad I’ll go to the local lighting store to see about a replacement. It should work much like the ones you tested in the video, correct?

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- John
  July 24, 2012 @ 12:28 pm
  
  Yes, all the same principals apply. A rheostat is just a variable resistor. Imagine the potentiometer shown in the video, but with only the center lug and one side lug. The varying resistance between those two lugs as you rotate the shaft is just like a rheostat.
  
  Reply
erik6297
August 30, 2012 @ 2:25 pm

I recently replaced my volume pot because it wore out. I replaced it with a CTS pot. I currently play a lot of VanHalen and I now realize that the CTS pot is too firm for me to turn quickly. Do you know if there is a way that I could make the pot turn easier without breaking it?

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- John
  August 30, 2012 @ 2:47 pm
  
  You could remove the pot back and clean out the grease there, but I’m not sure it would give you the feel you’re looking for. It’s probably easier to just replace the pot.
  
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- cgravier
  September 4, 2012 @ 3:13 pm
  
  i have a set of bourns EVh low friction pots. they turn very easy. expensive and not better quality than CTS but they do indeed turn easier.
  
  Reply
amerweb
September 2, 2012 @ 1:16 pm

Very informative! Thank you!

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manifestgtr
September 5, 2012 @ 11:47 pm

dude…you are really good at explaining things…normally, I’ll watch a video like this and the person doing it is so steeped in the subject that they just cant or don’t bother to explain it in a way that’s easily digestible…awesome video

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BeaDert8
September 18, 2012 @ 3:49 am

Amazing +thumbs up, please check out my funny Channel,thanks!
hughs from Germany+++love you°!°

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9999science
September 23, 2012 @ 6:31 am

great video, very good explanation thanks!

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jpodejko
September 28, 2012 @ 7:54 pm

I’m using a AA battery for a project I’m working on and I wanted to be able to limit the voltage with a potentiometer. The battery only gives a current of 2 amps which gives .75 ohms of resistance. Does this mean that I need a potentiometer that is within that range? I’ve been trying to learn about this today and I don’t seem to quite get it yet.

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- John
  October 16, 2012 @ 9:40 am
  
  That would be the maximum current draw of the battery. Instead, ask yourself how much current is *needed* to do the work you want to do with the circuit. Let’s go back to Ohm’s law V=IR (voltage = current * resistance). Start with what you know- the AA battery’s voltage is 1.5V, and your required current is I. Just plug it in to R=V/I and you’ll have your resistance.
  
  Reply
MrHkvideo18
October 16, 2012 @ 1:24 am

awesome explanation! 😀 Thanks!

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DmytriE
October 16, 2012 @ 9:25 pm

Fantastic explanation! Really helped me understand pots. We were using them in my physics class and was confused. Now I know exactly how to wire them and use them properly. 🙂 Thanks again!

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Mohammed Jaih
October 20, 2012 @ 6:59 pm

Thank you very Much Bro that was Easy to understand. Appreciate it.

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MrJohnny56789
October 30, 2012 @ 4:00 am

I bought two alpha pots recently. One was actually cheap, but it is a logarithmic (or imitation) volume 1MOhm and the other a 500KOhm blend pot. the 500k is tough to turn which is prtobably good for keeping your PU balance where you want it, while the 1MOhm is really easy to turn. the 1MOhm has the shiny aluminum metal and brass like we see here, while the 500k is one of those tiny crap-pot cast jobs. funnily enough, the crap looking one moves very smooth, and makes no noise, the shiny does oppo

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tpawlowskis
November 10, 2012 @ 8:33 am

hahaha he said wafer

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kannon11t
November 12, 2012 @ 9:44 pm

Bass broke so I figured I’d learn all about the parts, thanks for the details, I’ve been playing with the pots for days XD

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Youtube TV
November 17, 2012 @ 2:19 am

My single led is very dim turning up full power when using a 100k Potentiometer from 2 AA Battery…
but when I connect the led directly to the 2 AA battery, it’s very bright. I’m not sure if this is the right potentiometer,, please help!!

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- John
  November 22, 2012 @ 10:11 pm
  
  If your circuit is a simple series battery->resistor->LED, then you know the voltage drops across the LED and resistor must add up to the battery voltage. A typical LED drops about 2V and wants about 10mA current (depending on the LED color) . So with a 3V battery, the resistor/pot should drop 1V and will have the same 10mA current running through it. So Ohm’s law says R=V/I = 1V/.01mA = 100ohm. So obviously a 100k pot is way too high. Experiment with a 1k pot in series with a 100ohm resistor.
  
  Reply
  - Youtube TV
    November 25, 2012 @ 3:21 am
    
    Thanks for replying! I will sure to try this.. well.. back to Ebay for a 1k pot.
    
    Reply
The8BitChef
November 18, 2012 @ 9:26 pm

so is the center pin always the “out”?

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- John
  November 22, 2012 @ 10:54 pm
  
  Not necessarily. It depends on the circuit. For example, in a typical guitar tone circuit, you only use two lugs (center and one side), as a variable resistor, and it doesn’t really matter which one is “in” and “out”.
  
  Reply
mariusmssj
December 20, 2012 @ 7:48 am

This is absolutely brilliant. Came here to learn about Potentiometers and I did. Many thanks 🙂

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Derek Lopes
December 30, 2012 @ 4:41 pm

I have a circuit that goes like this: power (3.3v) to potentiometer (250k) to a fan. I want to be able to monitor the speed of the fan with a potentiometer but no matter how I position the wires on the potentiometer (input in the middle, output on the side, or vice versa) it always blasts at full speed. Is my potentiometer just bad, am I using the wrong type of potentiometer, or am I doing something wrong?

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- John
  December 30, 2012 @ 10:46 pm
  
  Fan speed control is trickier than you might think- typically involves PWM. Here’s a useful article- youtube won’t let me post a link, google for “bearblain fan speed control”
  
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- koncertLive
  January 24, 2013 @ 6:15 pm
  
  yeah you can make the potentiometer control you pulse speeds kinda like how you would dim a LED.. Sort of like turning it on and off really fast to make it run slower instead of lowering the voltage!.
  
  Reply
Inget Namn
January 9, 2013 @ 1:05 pm

Great video! Thanks man

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João Pedro
February 6, 2013 @ 3:00 pm

If I have a led in first and middle positions if i turn to one way it turns on and if I turn the other way it goes off? if don’t, what do I need to do on/off smoothly? ty

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- John
  February 6, 2013 @ 3:13 pm
  
  You need to pick a potentiometer of the right value, and put it in series with a small resistor. For example, attached to a 9v battery, you’d typically use a resistor between 2k and 5k as a current limiter for the LED. Less than 2k and it’ll be very bright and probably burn out. Greater than 5k or so, and it won’t be very bright. E.g try a 5k pot in series with a 2k resistor.
  
  Reply
  - João Pedro
    February 7, 2013 @ 3:00 pm
    
    I’m trying to do a steering wheel for pc with potentiometers, but when I connect A and D to the potentiometer it is activating the 2 letters so it’s doing adadadadadadadada, and tried to remove a little of middle inside (positive connector) it worked +/-, but when I’m playing I rotate a little to the right and it goes like if I have rotate it fully. what can I do?
    
    Reply
    - John
      February 12, 2013 @ 3:57 pm
      
      If I understand you correctly, you’re modifying a computer keyboard and connecting a potentiometer to the contacts normally connected to the A and D keys (which I assume are Left and Right in your driving game?) If so, all you can expect to achieve is the equivalent of pressing the A and D keys, in other words, hard right or left. I can’t imagine you’ll get very good results with this approach. A better approach may be to modify a game controller which has a continuous analog controller.
      
      Reply
100chuckjones
March 22, 2013 @ 4:11 pm

I do tutorials myself so I know what im talking about when I say this is a very well put together tutorial, more like a small seminar 🙂

great job

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Scum71succer
March 30, 2013 @ 8:02 am

Wish I had you for my science teacher

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J.L. Mealer
March 31, 2013 @ 9:24 pm

Thank you

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thommosa
April 20, 2013 @ 5:55 pm

You probably get lots of questions like this but what is the meaning of 100K or 50K? I am trying to slow a small 70RPM DC motor that runs 12V it can operate between 4.5-18V so I would like to ba able to vary the speed what kind of pot am I looking for does this 100K have something to do with it?

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- John
  April 23, 2013 @ 11:26 am
  
  The “K” means 1000. 100k is 100,000 ohms, and 50k is 50,000 ohms. “Ohm” is a measurement of resistance.
  Controlling a DC motor speed with a pot is not very efficient, and it will heat up. It is more common to use PWM, which pulses the voltage to the motor. You can use a very cheap, common chip like the 555 timer to do PWM.
  
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  - irfan haizan
    April 23, 2013 @ 10:08 pm
    
    sorry sir, just asking.. actually im facing same problem as thommosa.. my VR also easily heat up, im using 10k vr for 12v motor. and would you explain me more about the suitable component to control the motor speed.. and can i have your email for a better conversation.. 🙂 .. i will very appreciate you commitment sir.. thank you .. this is my email.. [email protected]
    
    Reply
    - John
      April 25, 2013 @ 3:14 pm
      
      Just search for “555 timer dc motor control” – you’ll find many tutorials, how-to’s and videos.
      
      Reply
  - icefighter35
    May 14, 2013 @ 1:30 pm
    
    sorry, but is it the pot or the dc motor that heat up? I need a pot for a dc train transformer, does it already have pwm?
    
    Reply
    - John
      May 16, 2013 @ 1:18 pm
      
      The potentiometer will get hot as it dissipates the power. PWM is a technique of controlling motor speed by essentially switching the power on and off rapidly (pulse width modulation), and requires a small circuit to do the PWM.
      
      Reply
hosswildcat
April 26, 2013 @ 6:48 am

Excellent video. Subbed.

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IngenieroDeSonido Juan Franco Picasso
April 29, 2013 @ 1:36 pm

Perfect explanation, I’m sharing it on my facebook and twitter for my students. Thanks!

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loganmapes7253
May 2, 2013 @ 7:52 pm

I want to use a pot for regulating an alternator’s voltage to a 12 volt deep cycle battery. What pot should I use for 14 volts at 100 amps? Thanks!

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icefighter35
May 7, 2013 @ 4:17 pm

is there a name for a potentiometer that will operate both directions of a dc motor depending on turning direction of the pot?

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- John
  May 14, 2013 @ 9:17 am
  
  As far as I know, there is no single potentiometer part that does what you want. The name for the circuit that will accomplish it is “Bi-directional DC Motor Speed Controller”
  
  Reply
nmssis
May 11, 2013 @ 2:10 pm

your vid posts are like a breath of fresh air for novices like me.

Thanks for posting

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thec4ke
May 13, 2013 @ 8:51 pm

Great job I understood everything!

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Angel LaHash
May 14, 2013 @ 12:20 pm

Time 2min you show a Naked Pot, with Arms(Brushs) opsite sides. Lets LEFT be to the Jack and RIGHT to Earth, so when the Arm on the POT reachs all the way to RIGHT you cut ever side of were the ARM on the COMMON sits, making it VOID, with it being a CIRCUIT it sill connects all around
May take some FINE TUNING

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davidcapi
May 16, 2013 @ 11:33 pm

Hey, very informative vid. Do you have any idea where I can buy a 12mm dual shaft, multi-gauged potentiometer for replacing the one on a blackstar ht dual pedal?

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- John
  May 21, 2013 @ 9:58 am
  
  Search for mini concentric stacked pots. You’ll find them at guitarpartsresource, allparts, etc. If you can’t find an exact match, you could contact blackstar directly to see if they have replacement parts.
  
  Reply
CoffinSupply
June 14, 2013 @ 6:33 pm

you must be an audio engineer?

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- John
  June 20, 2013 @ 3:57 pm
  
  I work in as a software engineer in pro audio. See my blog at planetz for more info, and FAQ’s and other resources.
  
  Reply
CannonfireProduction
June 18, 2013 @ 5:44 am

I think you may have inadvertently solved a problem. I was getting no sound from my guitar. Did the usual jack tests and all was fine. I narrowed it down to the vol pot. If I bypassed it with a jump wire current flowed. When I peeked through the gap in the pot I could see a little something hanging down but not touching the bottom of the pot. Assuming this was crud I gave it a flush through and the piece vanished. Still no output. This must have been the broken the sweeper. Am I correct?

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- John
  June 20, 2013 @ 3:59 pm
  
  It would be unusual for the wiper to break , but it’s possible. Sounds like it’s time for a new pot 🙂
  
  Reply
  - CannonfireProduction
    June 20, 2013 @ 4:41 pm
    
    Thanks John. I went for a new push/push pot (might as well do a Gilmour mod if I’ve got to change the pot). Not put it on yet but the flow tests are completely different to my old pot, ie they’re correct! What a relief, but interesting to know that a pot can die just like that. Love the idea of a troubleshooter vid if you’re up for it. It’ll save the world from restless nights and brain ache.
    
    Reply
Brandon Rainville
June 18, 2013 @ 7:04 pm

How are dimmer switches and potentiometers similar and how do they differ?
I’m a bit curious as to the possibilities using one or the other.

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- John
  June 20, 2013 @ 4:04 pm
  
  As far as I understand it, the simplest light dimmer is a variable resistor – which is just like the center lug and one side-lug of a potentiometer. But as with DC motor control, too much power is dissipated as heat when using a variable resistor as a dimmer, so modern dimmers use a different type of circuit to rapidly switch on and off, which is more efficient.
  
  Reply
levych
June 25, 2013 @ 8:19 pm

excellent explanation

Reply
Gettutorialized
June 30, 2013 @ 11:22 am

Gr8 explanation!
i want to vary a 12volts dc supply (1A) with a pot linearly
what shall be the resistance of my pot and how to calculate ?

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Peter Owens
July 3, 2013 @ 11:08 pm

Might have been helpful to mention briefly the existence of multi-turn pots.
I know they are of little interest re guitars etc.

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stavros houiris
July 4, 2013 @ 6:13 pm

can you make a video for the 4 pin Potentiometers???please

Reply
- John
  July 11, 2013 @ 8:55 am
  
  Your best approach is to use a multimeter and measure the resistance between the various pins, turning the pot. Write it all down, and it should become clear what’s what.
  
  Reply
  - stavros houiris
    July 11, 2013 @ 6:38 pm
    
    Thank you so much for taking the time to rite me back and i find your reply rely helpful, thanks.
    
    Reply
David
July 4, 2013 @ 2:08 pm

Hi John,

Thanks for the great video. I’m left handed and CTS offers a reverse audio taper pot in 250 and 500K

http://www.guitarelectronics.com/product/CPC250R/CTS-250K-Reverse-Audio-TaperLefty-Volume-Tone-Pot.html

I noticed is your video at around 2:16 minutes in when you have the CTS pot disassembled that the outer ring has less (or no) resistive material near the right lug compared to the left one. Does that mean there’s no resistance in that area or is contact broken? I suspect that maybe the outer ring on the reverse taper pot would be the opposite. Your thoughts please.

Thanks

Reply
- John
  July 10, 2013 @ 9:15 pm
  
  Hi David,
  Actually, I think what you’re seeing is simply the metallic overlay onto the darker-colored conductive material. This metal is what the pot lug is connected to. If you look carefully, you can see that the dark-colored conductive ring goes all the way around (you can just see the outline of it, around that copper-colored metallic overlay).
  The left side is the same as the right- it’s just the lighting made it harder to see.
  -John
  
  Reply
Robert Robinson
July 8, 2013 @ 5:07 pm

Are these pots capable of going to 11?

Reply
- John
  July 11, 2013 @ 9:03 am
  
  Paint them black, and they’ll go to 11.
  
  Reply
  - oceanrefusesnoriver
    August 10, 2013 @ 12:49 pm
    
    that is awesome, thanks for the lol
    
    Reply
awad alteemawy
July 24, 2013 @ 7:24 am

Reply
Андрей Андрейчук
July 28, 2013 @ 1:52 am

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Charles Hague
July 31, 2013 @ 3:03 pm

Thanks for this excellent tutorial! It is a great help in diagnosing a volume control problem for a virtual organ!

Reply
oceanrefusesnoriver
August 10, 2013 @ 12:49 pm

great, thank you

Reply
m5439703
August 19, 2013 @ 3:34 pm

Can I use a potentiometer with 84volts DC and LEDs, and if so what kind

Reply
Florida Scolas
August 22, 2013 @ 2:02 pm

Hi, I have a dual ganged potentiometer, is it like a regular potentiometer but with double the connectors?

Reply
- John
  August 22, 2013 @ 2:07 pm
  
  A dual gang pot is like two independent pots, stacked on top of each other, and controlled by the same shaft.
  
  Reply
Florida Scolas
August 22, 2013 @ 3:49 pm

Thanks!! I am going to make a little headphone amp using this. If I where to attach the input in one line of tabs and the out put in another then bridge the two, would that work?

Reply
- John
  August 23, 2013 @ 8:50 am
  
  You won’t need to bridge the two (except they will share a common ground). Your left and right audio signals are independent, and should be treated independently with the two pots in your dual-gang pot.
  
  Reply
Izrun
August 27, 2013 @ 12:20 pm

What do they use in systems with double knobs, like they usually use in some oscilloscopes? Are those not pots but rotary encoders?

Reply
- John
  August 27, 2013 @ 1:14 pm
  
  A dual-concentric pot is like two pots stacked on top of each other, with an inner control shaft and an outer control shaft, allowing two concentric knob controls.
  
  Reply
manometians
August 29, 2013 @ 6:24 pm

I have a pot-.05 watts <47mv 3amps 30vdc...looks like the one in your vid, but it has 3 poles on the back also. Can I use this in-line with a speaker to control it's level? How would you wire it? Thanks.

Reply
tonytee91
September 19, 2013 @ 11:26 am

that was a really good video

Reply
Aaron Binder
September 25, 2013 @ 10:16 pm

Ahhh very cool man!! TY for that video. I have a 16 watt tube amp I bought from Tube Depot and I’m on my 3rd Potentiometer. I keep getting the ones from Parts Express and they are total crap!! After watching your video now I have a better idea of where to look for a better POT . Thanks again!! Looking forward to watching more of your videos. Take care

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robviolin1
September 28, 2013 @ 12:12 pm

Thanks

Reply
1marcelfilms
October 20, 2013 @ 11:53 am

i need one that goes from 0 to infinite

Reply
cvmbh4life09
November 2, 2013 @ 4:20 pm

great video!! useful for automotive applications. currently troubleshooting throttle position sensor!

Reply
Michael Evans
November 21, 2013 @ 1:31 pm

looking good 🙂

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Ron Dean
December 4, 2013 @ 4:11 pm

Excellent video, thanks.

Reply
Flylikechris
December 4, 2013 @ 6:28 pm

Phenomenal, thanks for the video!

Reply
replytosender
December 23, 2013 @ 4:35 am

Nicely done.

Reply
Tormy Van Cool
December 28, 2013 @ 3:23 am

i have difficulty to find good potentiometers. When you buy a pedal or an
amp, you notice how soft these potentiometers are. When I go to shop to buy
them, I get always crapy stuff and after 2 days are crackling. Do you have
any suggestion?

Reply
auddict
December 28, 2013 @ 3:43 pm

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gary reed
January 14, 2014 @ 3:19 pm

Great job, crystal clear explanation, thanks.

Reply
Joey Crowle
January 19, 2014 @ 8:22 am

very well done explanation. Thanks!

Reply
joe w
January 23, 2014 @ 12:05 pm

Great video, thanks!

Reply
Cody Choules
January 26, 2014 @ 9:37 pm

I need some help. If I want to give my circuit a “clutch throttle”
relationship where a primary variable is limited by a secondary variable
could I use two photometers? I have tried hooking them together but for
some reason they are not working they way I want. Gould any one help me
out.

Reply
John Cooper
February 2, 2014 @ 10:03 pm

@Tormy Van Cool – I buy Alpha, CTS and Bourns pots, from places like
stewmac, pedalpartsplus, mouser, etc.

Reply
Alfonso Pérez-Andújar Cavestany
February 4, 2014 @ 7:29 am

Great video dude

Reply
ck9000
February 8, 2014 @ 9:58 pm

Great video, thanks for educating me

Reply
rogerwilco99
February 10, 2014 @ 11:26 pm

One minor mistake, here. My apologies if someone has already pointed it out.

When you increase the thickness of the ring in a log pot, the resistance
goes DOWN per linear millimeter where it gets wider/thicker. It’s like
parallel resisters. The more you have the lower the resistance. Otherwise,
this is a great video with nicely explained information.

I know it’s somewhat counter-intuitive to say that when the distance
increases the resistance does, too. But if the ring gets thicker or wider
the resistance goes down. Your mind tries to group thicker/wider with
longer because either means more resistive material to flow through. But
each electron only takes a single path, no matter how many resisters there
are in parallel. In thicker wider ring material there are more pathways for
the electron flow and thus lower resistance because more electrons can flow
at the same time. The length of the ring is analogous to serial resisters
put end to end (and some are exactly that). But thicker or wider ring
material is analogous to more resisters in parallel. In series we add
resistances. But in parallel we use the square over sum method.

Two 100 ohm resisters in series equals 100+100=200 ohms. Two 100 ohm
resisters in parallel is calculated as 100*100/100+100 or 10000/200=50
ohms. Those of you who are well versed in electronics already know that.
But I assume there are others who do not.

I buy Alpha pots for my amp work. But I put CTS usually for my guitar work.
Sometimes, I’ll use a CTS pot in an amp if that’s what was there before, or
a Bourns. I’ve never had an Alpha pot fail on me. Sometimes they need a
little cleaning but then they’re good to go. I have had a couple of CTS
pots fail on me over the last 40 years. I can be fairly rough on my gear.

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LevikTech
February 12, 2014 @ 3:29 am

I’m working on a RC Car controlled through wifi using either a physical
controller or a computer. I have been, and will continue to upload progress
updates and possibly various Arduino tutorials in the future. Check my
channel out!

Reply
Ohms Law
February 16, 2014 @ 4:24 pm

John I need to add a pot to my guitar I have an LTD guitar with two double
hum bucker and only one pot for both of them. I want to add another pot so
I can have a volume control for each pickup so I can do the volume toggle
trick on my guitar. The way it is now this pot control both of them so I
cant have one turned up and have the other turned down to switch between
them with the toggle switch. Is this possible oh yeah they are active
pickups is this still possible to do.

Reply
Gautham Jogi
February 22, 2014 @ 8:17 am

supper….thanks fore ur information.

Reply
FyingHigh Again
March 16, 2014 @ 7:25 am

I really could use some help. I upgraded my Strat. I removed the single
coil in the bridge position and replaced it with a Seymour Duncan Hotrail.
The guy at the shop said to change the 250k pot with a 500k pot for the
increased output of the humbucker. So I bought a CTS 500ka pot and soldered
it in exactly the way the old one was (I think) The pickup and everything
works, but the new “volume” pot does not control the volume! It does affect
the tone, but more like a tone pot rather than a volume pot. What have I
done? It actually sounds very loud and very powerful, but it’s wide ass
open the whole time. Any ideas?

Reply
bigblockelectra
March 24, 2014 @ 10:31 pm

with all the youtube videos of monkeys smoking cigarettes, homemade
fireworks gone wrong, and skiing accidents, it is nice to know that a video
like this has 100k+ views and professionals are still posting interesting
things. I’m not an old man by the way.

Reply
bigblockelectra
March 24, 2014 @ 10:42 pm

I have a ’78 Lincoln Continental with a dimming headlight switch. The pot
that you can turn on the dashboard will dim all the clock and gauge cluster
lighting. There is a “dead” spot on the pot where if I turn to that
position (happens to be the max brightness). Now, if the original Ford
part was like the CTS design and had the stiff bent contacts, do you think
the reason there is a dead spot and slight intermittency in that area of
the pot is because those stiff contacts are a little word out? I would
like to replace it, but my car has an auto headlight dimmer and the
headlight switch is built into the gauge cluster dimmer, so it is a hard
part to find since not all models had autodim.

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Edwin Henry Blachford
April 7, 2014 @ 1:17 am

very clear Yoda. thankyou

Reply
thtrgeek
April 27, 2014 @ 6:24 am

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Daniel Phillips
April 28, 2014 @ 1:12 pm

Thanks for sharing this info. I am currently researching for a project. I
am going to update an antique radio and am looking for details about how to
choose the right parts for volume control, and radio dial. the radio dial i
want it to still show the pin pointing at frequency but also send a digital
signal to the raspberry pi, i believe that part is a rotary encoder. any
suggestions on parts or similar projects would be greatly appreciated.
thanks

Reply
Ilana Kashi
May 1, 2014 @ 6:13 am

Lovely

Reply
D&M
May 8, 2014 @ 2:08 pm

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pleximanic
May 28, 2014 @ 4:50 am

Bourns low friction pots rules when it comes to feel and tapper!
The old vintage CTS were pretty good but the new ones are WAY to hard to
turn!

Reply
Nahid Muzammil
July 1, 2014 @ 11:54 pm

Hey thanks, this was a great video.

Can you direct me to a link that explains how infinite rotation
potentiometer works? Also, can you let me know if you know of a sit where I
can buy them online?

Thanks again 🙂

Reply
Nick Zeak
August 2, 2014 @ 6:23 pm

Hi there, could you do a video about what the different functions of the
lugs are? I notice the middle one is separate from the outer two, and I’m
having a little trouble understanding schematics without that piece of
information. Thank you!

Reply
Shaun Sanders
August 8, 2014 @ 4:21 pm

Very nice tutorial. Thanks.

Reply
St. Hugh
August 11, 2014 @ 8:28 pm

Hi John,

I’m looking for a pair of 250K pots where you only need to turn the
knob/wiper about half the distance of a normal pot in order to go from 0 to
10 (or no resistance to full resistance). Do you know of such a pot? Or do
you know anyone who will custom make a pair for me? Thanks!

Reply
houseoffire72
August 28, 2014 @ 3:42 am

Nice one Maha..!

Reply
Amr M. Kamel
September 9, 2014 @ 9:23 am

Thank you I really had hard time understanding how pots work but now its
piece of cake thanks to you 🙂

Reply
Okechukwu Igbokwe
November 1, 2014 @ 9:33 am

I was just wondering if outer lugs are biased one way vs. another, eg. you
can’t just connect the lead and ground to either lug.

Reply
Richard Mullins
November 4, 2014 @ 6:08 pm

good stuff, man, artfully presented, professionally researched. Loves

Reply
Kevin Ly
November 11, 2014 @ 6:47 pm

#DTFACERTHOUGH

Reply
ömer cenk akpınar
November 13, 2014 @ 8:23 pm

thank you verymuch , very useful video.

Reply
Rob Wentz
November 14, 2014 @ 9:40 am

excellent explanations and demonstration on how the variety of pots work
and how they’re manufactured.

Reply
Mike Herbst
December 4, 2014 @ 4:18 am

Very pleasant voice – can very well listened (is important in tutorials:-)
)

Reply
Buzzin B
December 4, 2014 @ 1:25 pm

It will be the most Wonderful time of the year in 21 days! Woohoo

Reply
Billo1281
January 20, 2015 @ 6:17 pm

Thank you!

Reply
Richard Couture
February 14, 2015 @ 10:35 am

Thanks for taking the time to do this for others. It was very informative
and well done.

Reply
TheButcher6969
February 19, 2015 @ 10:19 pm

How do you test a dual potentiometer to see if it’s good?

Reply
Pallab Das
March 17, 2015 @ 1:11 pm

Sir Can I use a rotary potentiometer as led dimmer [ my purpose is to
increase – decrease the led light intensity], As I am learning Electronics
could you please tell me what capacity rotary potentiometer will I need to
work with 12V dc devices. [0.43Amp] and other 12v dc led strip 2mtrs I dont
know the Amp and watt.

Reply
mykwilwin
March 23, 2015 @ 8:11 am

I have an old lasonic boombox im trying to fix and the volume remains at
the lowest even when I turn the knob.. anyways my potentiometer looks
almost like yours but I have 7 pins? I took apart and lightly sanded to
clean up the surface.. probably best to replace since I sanded through the
black material (I thought it was tarnished copper)

Reply
An Everyman
March 30, 2015 @ 2:15 am

Hi John, do you know what a cosine potentiometer is?

Reply
futchofdeth666
April 11, 2015 @ 8:26 pm

Thank You Sir! Bass guitar stopped working, checked everything with
multimeter couldn’t figure it out. Watched your vid, took mine apart and
back together, tighter with the clips. I assume it just was a bad
connection inside, works now and I understand pots!

Reply
jvm alum
May 24, 2015 @ 12:28 pm

Hi, I recently installed a 50’s wiring harness on my les paul. It consisted
of pots bumble bee caps a switchcraft togle and the jack, all sheilded
wire. When I soldered everything together the volumes ‘both’ don’t start to
work until about #7 and the tone controls seem to do nothing. I don’t see
any grounding issues. Does this sound in any way familier to you, ring any
bells. Does it sound like ground, defective parts, something wired to
wrong place. I was hoping you mght be able to shed some light based on the
informatin Iv’e givven you. If you get this and have any suggestions I
would greatly appreciate it. Thanks, James

Reply
jvm alum
June 3, 2015 @ 4:32 am

Hi again John, I was hoping you might consider my problem a little further.
Do you think if I put to much heat to the pots and that warped the materiel
the carbon paths are on that that might cause the effect that I’m getting.
if the boards are warped they may only make contact at certain points,
kinda strange that it would be at the same point on both pots but??? I
don’t know. What do you think? Thanks for the past and present
consideration. James

Reply
Scott Wilson
July 27, 2015 @ 8:36 am

Thank you! You are an awesome teacher

Reply
Damien Carlisle
August 1, 2015 @ 9:42 am

Great video. Thank you for making this.

Reply

Pots, Wafers, Wipers, Shafts, Dimples

191 Comments

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