Create a two stage potentiometer

Posted on by Stephen Smith

Sometimes we find that a particular pickup (or pickups) are a little too bright for our guitars. Traditionally humbuckers are darker and manufacturers chose to use 500K potentiometers to ensure the pickup didn’t sound too dark or muddy. Single coil pickups in contrast sound quite a bit brighter, and manufacturers chose to use 250K potentiometers to tame the brightness.

These traditional potentiometer choices don’t always work with some pickups though. The Seymour Duncan JB was originally designed for use with 250K potentiometers. As a result some have found the JB to sound quite bright in many guitars that are equipped with 500K potentiometers.

Many guitars also come with a combination of single coil and humbucker pickups. Running a 500K potentiometer when using singles may make them too sharp and shrill. Sure you can have a couple of volume potentiometers, one for each sort of pickup. But what if you want to keep your control layout simple?

Materials required to make a two stage potentiometer.

The solution is to make what I’m calling a two stage potentiometer. We only need a few things to make this: a 500K volume pot, a 470K or 510K resistor (you can’t get 500K ones), some wire, and a DPDT switch (double pole-double throw). To save on holes in your guitar or pickguard it’s probably best to use a push-pull or push-push volume pot. I didn’t have one handy, so to demonstrate I’m using a separate DPDT switch.

Roll your volume potentiometer completely counter-clockwise, and measure the two outer lugs with your multimeter set to read Ohms (2MOhms on my meter), and your potentiometer should be about 500K. You’ll be lucky if it’s exact, resistors and potentiometers are rarely to spec.

Do the same thing with your resistor. I used a 510K metal film resistor as they typically have far closer tolerances than carbon film ones. The combination of the potentiometer and resistor will get me close enough to a 250K reading for the second stage of my two stage potentiometer.

The two stage potentiometer wiring diagram - simple as!

Cut two appropriate lengths of wire and solder them to the two middle lugs on your DPDT switch or push-pull potentiometer. This will be the bridge to the two outer lugs of your potentiometer.

Solder the resistor to the two lugs on one end of your switch or push-pull potentiometer. The two on the opposing side will be left alone, and will give you your default 500K setting.

Take the ends of the two wires and solder them to the the two outer lugs of your 500K potentiometer. Now you have a two stage 500K/250K potentiometer!

In stock 500K mode - and 250K mode.

Test the potentiometer on your multimeter by attaching the probes to the two outer lugs of your potentiometer. One side of your switch will read around 500K, the other will be around 250K.

Wire your volume potentiometer in to your guitar as normal, and make the appropriate hole if you are using a separate DPDT switch, and you are ready to go. Overly bright pickups will no longer be an issue for you as you can quickly switch your potentiometer to suit almost anything.

Written on July 15, 2012, by Stephen Smith

Other posts by

This entry was posted in: , and tagged , , , , , , , , , , , . Bookmark the Permalink

Comments (17)

  • Stephen Smith 6 years ago

    Great idea. I’d love to see a video or audio clip demonstrating the difference in sound!

  • Stephen Smith 6 years ago

    Simple and yet…AWSOME!!! Whoever thought of this should be a multi-millionaire. The main reason for the high “grade” is in it’s simplicity. Saves you from another hole in your guitar, keeps the “stock” look and does a great job of 2 different ohm settings in ONE simple package, just brilliant!!!

  • Stephen Smith 6 years ago

    Great post. I will take this as the basis for my 500/250 K article, but where this is very much practice-driven I will be talking math and physics. I will endeavor to find an answer to why a 250k bleeds away more highs than a 250k and why different pot values work differently in different applications. Should be fun!

  • Stephen Smith 6 years ago

    Anyone out there have a wiring diagram on a D-tar piezo pickup with one or two added magnetic pickups? From what I understand, Seymour Duncan doesnt have a diagram for this setup.

    Steveo

  • Stephen Smith 6 years ago

    Glad you liked the idea. It just came to me a few weeks ago, while thinking about the issues that people have with the JB for example. So simple, I was surprised no one else had thought of it (although I’m sure someone has). 

  • Stephen Smith 6 years ago

     This is just awesome, I wish you could make a video about this so we can see the sound difference. Will try this with my own guitar and see that difference.

  • Stephen Smith 6 years ago

    Awesome idea! Even better then having it as a seperate switch is too switch it automatically with the pickups.
    Especially for things like split coils, HSS setups and pickups like the P-Rails it would be great to switch in the resistor immediately when switching to a single coil.

  • Stephen Smith 6 years ago

    Would you only use it on the volume? What about a Volume/Tone contoll set up, how would that work? I’m thinking of trying this idea out & wonder if id have to connect it the tome pot as well.

  • Stephen Smith 6 years ago

     I like the idea to quickly test pickups and tones in a pickguard with the Liberator. Suggestion: Could you add an example to apply this idea in a HSS and 5 position switch so it automatically goes to 250k for neck/middle and to 500k when using bridge for 500k compatible HBs?

    I just have one weird question: If JB was designed with 250K pots in mind then why the existing wiring diagram does not highlight that? I got a JB my self and I am using 250k because of I gave priority to neck/middle single coils. On the other hand what kind of pot are charvel, jackson and other using for the 59/JB combo?

    Thanks for posting it, I really liked the concept.

  • Stephen Smith 6 years ago

    I just tried this on a 500K tone pot. Guitar also has a 500K volume pot. I didn’t hear a difference after doing this mod. I know the article is geared toward doing the mod on the volume pot vs. the tone pot, but a little suprised that there seems to be zero difference on the tone pot (?)

    • Stephen Smith 6 years ago

      Oh, I did verify after making the solder connections with a multimeter that the pot operated in both stages as it should, before I installed the pot in the guitar.

  • Stephen Smith 6 years ago

    This is pretty cool if you have a guitar.

  • Stephen Smith 6 years ago

    Or, if you’ve got enough room in your control cavity, you could use a stacked pot (as in, two wiper sections with separate solder pads and one shared shaft, not the concentric ones that have two independant shafts), 500k/250k, and wire it as two volume controls. No switch needed. Schematics easily available (2 volume, 2 volume and 1 tone, 2 volume and 2 tone – whatever). No using resisters and having doubts about whether the taper stays just the same. I’ve seen metric stacked pots on eBay, so I’m pretty sure an imperial one shouldn’t be hard to find if you need that instead. Oh, and they are this pairing of values (at least some were). I’ve also seen these in electronics stores, but I don’t know what the quality or shaft diameter was like. I was planning on using a stacked pot myself if I encountered this sort of issue.
    (Don’t know if my terminology is off on stacked vs concentric – some people have used them interchangeably, slowing my efforts to find these and the two shaft one hole variety)

  • Stephen Smith 6 years ago

    Great great post. I have a question though:
    What about the tone potentiometer?
    In my Ibanez RG560 I have a 500KOhm volume pot and a 500KOhm Tone pot. It is an HSS configuration.
    I installed a JB Humbucker, along with Duckbuckers and Little’59. I am eager to try this mod to see if the tone gets a bit fatter, but what about the tone pot? Can it be a normal 500KOhm?
    Thanks.

    • Stephen Smith 6 years ago

      500k pots will work perfectly fine with that setup, but if you find that the tone is a little too bright for your taste after installing the pickups, dropping a 250k volume pot in your guitar will take the edge off. All the pickups you installed work well with either pot value.

  • Stephen Smith 6 years ago

    With HSS guitars you can just solder a 470/510 resistor from the pickup selector where the single coil is soldered, then referenced to ground. Voila, your Humbucker will read full resistance of the pot, while the single coils will read the parallel combination of pot and resistor, that is, ~250k.
    That will go automatically as you switch pickups while playing without need to turn one extra switch other than the pup selector itself.

Leave a Reply