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The Fender Delta Tone System, Pt. 2

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The Fender Delta Tone System, Pt. 2
In my previous column, we began a two-part series on Fender’s Delta Tone system, which includes “no-load” pots. After introducing the Delta Tone in 1997, Fender made it a feature of the American Standard Stratocaster, and the system is still in use today. For a full description of the Delta Tone system, check out the January 2011 installment of Mod Garage on premierguitar.com/jan2011.

Now, let’s take a closer look at no-load pots. Visually, it’s easy to identify a no-load pot, because of the detent dimple on the back of its enclosure. This is the mechanical spot where the pot clicks and goes completely open, removing itself from the circuit. Other than having this dimple, a no-load pot looks like any other guitar potentiometer.

The CTS no-load pots that are available from Fender aren’t very expensive, but if you like the tone pot you already have and don’t want to replace it, it’s not difficult to mod it to no-load specs—that’s assuming you can live without the detent function.

Here’s how to do it. First, unsolder and remove the pot you’d like to mod. The next step is to disassemble the pot. Using a pair of small needle-nose pliers, start this operation by bending the pot’s case tabs open. Next, remove the metal housing and lift out the carbon wiper tray with the soldering lugs. Place it in front of you exactly as shown in the photo shown here. Though your potentiometer might be a little different, it should look similar to this one.

Now take a sharp razor blade, X-ACTO knife, drill bit, Dremel tool, or a small needle file and cut the trace, right at the red line shown in the photo. Personally, I like to use a special file made for guitar nuts for this work, but you can use whatever you have at hand. Scrape off approximately 1/8" of the carbon and clean this area with a dust brush or a similar tool. That’s it.

Next, reassemble the pot and use the needle-nose pliers to push back each of the four case tabs. Reinstall the pot on the pickguard and resolder the wires. Voilà! With the pot fully opened, it will remove itself from the circuit. Now you have a no-load pot without any additional costs . . . but without the detent feature.

A side note: You might read that covering that area on the carbon wiper tray with nail polish will do the same trick as scraping off 1/8" of carbon. I don’t recommend this, because depending on the pot, the polish may not stick to the carbon taper. The “surgical method” outlined here is better.

To test your no-load pot, turn your pot so that the shaft is facing down and the lugs are facing up, and connect one lead of your digital multimeter (DMM) to the middle lug of the pot, and the other lead to the right lug. Next, set your DMM to resistance. With the pot turned all the way clockwise to 10, you should receive an open or “no reading.” If you turn the pot counter-clockwise to 9 or lower, the pot will function normally, and you should see readings that are close to the pot value and that decrease as you roll back toward 0.

Stay tuned for more Strat mods in the coming months. Next time, we’ll talk about the Fender “Greasebucket” tone control. Meanwhile, keep modding!


Dirk Wacker lives in Germany and is fascinated by anything related to old Fender guitars and amps. He plays country, rockabilly, and surf music in two bands, works regularly as a session musician for a local studio, and writes for several guitar mags. He’s also a hardcore guitar and amp DIY-er who runs an extensive website—singlecoil.com—on the subject.

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