Using Resistors In Guitars – 101
When you think of tone shaping, a couple of items might come to mind. We all use pickups, capacitors (tone caps), and pots as tone shapers. However, using Resistors in a guitar can open up new tonal possibilities as well.
A Resistor is a device with a measurable amount of resistance. Simply put, a Resistor impedes the flow of or “resists” electricity. One way to think of a resistor is by using the ‘Pipe analogy.’
Imagine a pipe with free-flowing water in it. Then, imagine that the water has to go through a much smaller gauge pipe where the flow is “resisted.” This analogy describes how a resistor works in simple terms: it creates a higher point of resistance in the flow of electricity.
I’m sure you’re thinking “Cool. But, how does a resistor affect my guitar?” We’re glad you asked! Today, we’re going to illustrate some basic examples of how to use resistors in a guitar.
PARTIAL SPLIT RESISTOR:
One of the most basic examples of resistors in a guitar is with our Partial Split Resistor. The Partial Split Resistor gives low-output humbuckers a stronger single-coil tone when split. This is a common problem when splitting your humbucker – not all humbuckers are equal.
Removing one coil from a lower-output humbucker, like our Pure P.A.F., leaves you with a weak-sounding single-coil tone. Using a resistor can make all the difference. For an in-depth article on coil-splitting, head to our article here.
HOW TO WIRE IT UP:
Using a Partial Tap Resistor is an easy way to explain resistors in a guitar. It takes the place of whatever you’re using to connect to ground. Instead of using wire as your ground connection, use a resistor instead. Using one will give you a stronger coil tapped tone when you pull up. See below for an illustration to help you wire it up.
HOW IT WORKS:
Simple. A Resistor is “Resisting” the flow of electricity, so, when you pull up, instead of sending 50% of the Humbucker to ground, it will only send, say, 33% of it. This allows you to have a stronger single-coil tone when pulled up.
FAKING OUT YOUR SINGLE COILS WITH RESISTORS:
Alright “faking out” seems a little vindictive. However, when you have a Telecaster with a Humbucker in the Neck and a Single Coil in the bridge, it can be tough to make those two pickups play nicely together (read our in-depth article on this topic here).
WHEN TO DO IT:
Let’s set the stage: You have a Telecaster with a Humbucker in the neck and a Single Coil in the Bridge. The Humbucker needs a 500K pot to sound good, and Single Coil sounds best on 250K pots. You only have one volume pot – how can you compromise? Put a Resistor From The Bridge Pickup Hot To Ground.
HOW TO WIRE IT UP:
HOW DOES IT WORK?
Let’s explain this using a simple formula. When you use two resistors in Parallel, one side of each resistor connects to the same location. For example, your Volume Pot is a resistor: 250K, 500K, these are resistance values.
One side of the pot is a “hot,” or “input,” and one side of the pot is Ground. If you attach a resistor from the “Hot” of a pickup, and one leg to “ground,” you’re putting that resistor in Parallel. See below for the equation of using 2 Resistors in Parallel:
As you see, if you put a 500K resistor in parallel with a 500K pot, the Bridge Pickup will “see” a 250K pot. This is great for your Telecaster as it you’ll have a great sounding Neck Humbucker and a perfect-sounding Bridge Single Coil.
The above formula works well when you’re on your Neck pickup and Bridge Pickup only. However, when you get in the Middle Position, you’re adding yet another resistor. Your Neck Pickup (500K) Your Bridge Pickup (500K) and the Parallel Resistor (~470K). When you combine your neck and bridge using this resistor trick, the middle position will see a 163K pot, making it darker than usual.
TRANSFORM YOUR POTS:
In our last example, you can use a resistor in a guitar to change your pot value. This is handy when you only have a 500K pot on hand, but you need a 250K pot. If you have a ~500K Resistor, you can make this happen! See below for a diagram on how to wire this up:
In the above image, you have a 470K resistor in Parallel with your Volume Pot. The pot value’s resistance is 500K, and your Resistor is 470K – with a combined resistance of 242K. Pretty neat!
You can use this trick to take a bit of high-end off of your pots as well. Let’s say you have a 500K pot, and your pickups are just a little too bright on them: you can add a 1Meg resistor like the image above, and you’ve turned your 500K pot into a 333K pot. This will tame some of the highs.
Thank you for reading. There are lots of great articles out there to learn how resistors work, and what you can use them for. There is a multitude of ways to add a resistor to your guitar’s kit. How do you do it?
Question regarding adding a resistor for S/H volume balance.
If when both pickups are selected in parallel, they both see the 500k volume pot, are you saying that normally (without the extra resistor) the pickups would see “250k” (500k & 500k)?
If this is correct, when adding a 470k resistor, wouldn’t both pickups also “see” the extra resistor when both selected since everything is connected, resulting in 500k+500k+470k+470k=121k and not 163k?
I guess the roof of my confusion is why do you count 500k twice if there is only 1 common 500k volume pot (like typical Strat).
Second question – I’m wanting to buy a hotter bridge single coil (P-90ish)for a Strat. So far the Dimarzio FS-1 & SDS-1 and the Seymour Duncan SSL-5, SSL-4, and SSL-3 have all disappointed and I’m stuck. Do you have a recommendation on what’s your hottest pickup? Could you do a overwound 44awg with fillister screws?
I have a bit of complex problem with a Tele. I have two (2 strand) P90s at middle and neck, with a Nocaster at bridge. I have 500k pots. As with many, I do not like the Nocaster through 500k. Would the resistor wire at the bridge as in the illustrations above, meaning, like a standard two pickup with a P90 and Nocaster bridge? Thank you in advance for your kind response, Dave
What a Resister for my 500K to have a 1 MOhm pot? must be a 1000 KOhm parallel?
I’m replacing a SD humbucker (bass guitar) with a Nordstrand. The SD pickup uses a three-way blade switch with a 3.3k ohm resistor for parallel/series/split. The Nordstrand wiring diagram indicates use of a three-way toggle switch. I imagine that the existing blade switch can be used in lieu of the toggle switch, but the impedance of the resistor may have to be adjusted for the impedance of the pickup. Is this a valid assumption?
Greetings. I would like to split coil a hot humbucker (4 wires), but I would not want a drop in volume when splitting it (as a single pickup). I would like to lower the output of the humbucker, as it is too hot for my taste, anyway, to somehow match it when split. Is this doable using a resistor between the humbucker’s hot wire and the pot? What value should it have? And how about the pot to suit both the humbucker and split coil modes?
Hey Jay, yes this is totally possible – check out our partial split resistor modification in this article. We use a 7K resistor between the center tap wires and ground to “partially split” a humbucker.
You can calculate the total resistance here:
(The formula and a diagram are on the same page.)
As far as I can see you can get at maximum a resistance equivalent to the smaller of the two resistors – literally the current goes the way of, well, least resistance. So you can’t increase the value of a pot this way, just decrease it. The higher you chose the parallel resistor’s value, the closer you get to the original value of the pot.
Hope this helps.