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Introduction to DIY Guitar Effects Pedals: A Simple Killswitch

Updated on July 24, 2013

An Introduction to DIY Guitar Effects

If you're interested in building your own DIY guitar effects pedals, it is often obviously easier to start off with a simpler build, and one of the simplest possible builds is a passive killswitch pedal. A passive pedal doesn't require a power source (like a battery). In case you don't know what a killswitch is, it is a momentary pushbutton switch that cuts the signal to a ground for as long as the switch is held down. If you had a hard time following that description, you are definitely reading the right article. I'll walk you through a simple building process and introduce to to the basics of pedal building. Now let's actually learn something.

Image from Tube-Town.net

Basic Terminology

We'll Be Using Some Pretty Big Words, Here's Your Dictionary for This Lesson.

  • Pushbutton switch - This is the switch you operate with your foot. There are many different kinds of switches, such as SPST, DPDT, and 3DPT, that you needn't worry about at this time. We are only working with one type of switch in this pedal. Here's a great article to help you understand switches!
  • Momentary switch - this is a switch that stays on only while you have it pressed.
  • SPST switch - this is a switch that is either completing a circuit (on), or shorting it (off). It does not switch between two different circuits. This is the type of switch that we will be working with today.
  • Normally closed ( N.C.) or normally open (N.O.) - these are terms used to describe a SPST momentary switch. A momentary switch that is N.C. means that it normally allows the circuit to flow freely. A momentary switch that is N.O. means that it normally shorts the circuit. When depressed, the switch will either open (N.C.) or close (N.O.) the circuit. Understanding this is probably the hardest part of this project.
  • Hot and ground wire - the hot wire is what will carry the signal in the pedal. The ground prevents hum and other noises. Both are essential in every circuit.

Supplies

Here's What You'll Need to Make This Happen:

Necessary

  • 3 Lengths of Electrical Hookup Wire (one long, two half the size of the long)
  • 1 SPST Momentary N.C. switch
  • 2 Female 1/4" Mono Input Jacks
  • Wire Cutters
  • Wire Strippers

Will Make It Easier

  • Needle Nose Pliers (optional)
  • Enclosure (optional)
  • Soldering Iron (Highly Recommended)
  • Solder (Needed for Soldering)

(You can aquire this entire list from Radioshack, though it may be cheaper and the parts may be more reliable from websites such as PedalPartsPlus, or SmallBear)

Jack Diagram
Jack Diagram

How It Works

A Light of Understanding...

Chances are you've replaced a light switch before. A killswitch is like the light switch for your guitar. As long as your foot is pushing down on this thing, the signal will be cut off and there will be nothing coming out of your amp, except maybe a bit of hum if you're using built in amp distortion. As soon as you release your foot, the signal will flow freely, and your setup will behave normally. How does this happen? It's pretty basic. Like a light switch, you are either breaking or completing the circuit depending on what position the switch is in.

All that's happening when the signal is cut is the hot wire is being shorted to a ground, basically breaking the circuit. And 7th grade science class tells us that when a circuit is broken, it doesn't work.

So there should be two tabs on your input jacks. As illustrated by the diagram to the right, one tab is a hot (carrying the signal) and one is a ground (keeping the pedal from making noise), which is also called the sleeve. Now it's time to start building, there are many different ways to make a killswitch pedal, but I am showing you what I think is the easiest.

image from guitarnucleus.com

Putting It Together

Finally Getting it to Work!

  1. Take the long piece of hookup wire and strip the coating off of the ends so the wire underneath is exposed. Then take that piece of wire, and connect the two ground tabs on the input jacks. You can either crimp the wire, or solder it, your choice (it will be more secure soldered, and will create less noise; it may unconnect if crimped).
  2. Take the two shorter pieces of hookup wire, and again, strip the ends of them. Then take one length of wire, and connect one of the hot tabs to one lug (joint) on the momentary switch. Then take the other length of wire, and attach the other hot tab to the other lug.
  3. If you're confused, please refer to the circuit diagram in the pictures. Here are the symbols for a schematic (in case you can't read it).
  4. Now test your pedal. If it works as expected and cuts out the signal when you press the button, then congratulations! You did everything right and completed your first pedal! If it didn't work, then you may need to troubleshoot a bit.

The Diagram

The Diagram
The Diagram

Troubleshooting

Have Issues? Let's Fix 'em!

Here are a couple common issues that I have found, and mistakes I have made:

  • The hookup wire is broken in some way, this could be either underneath the wire's shielding or exposed. Tug on the exposed wire and move the wire around to make sure it's not internally fractured.
  • The connections are not complete, this possible even if you soldered your connections. If you crimped your connections, make sure they are tight and won't fall off easily (or at all). If you soldered, make sure there are no bubbles or extra solder, and remove the extra with a solder braid.
  • A hot tab is connected to a ground tab. This is a mistake that I made. It results in significant volume and tone loss. Simply double check your tab connections.
  • Something conductive is touching something in the circuit, this could short the circuit.
  • Your momentary switch is N.O. instead of N.C., this will result in the signal passing through when the switch is depressed. Double check the type of switch you got
  • The switch isn't momentary, self explanatory. Again, double check the type of switch.

Enhancements

Always Room for Imrovement

  • Add an LED Indicator - this would require an entirely different switch along with a battery, and a whole new circuit. This will be easier later.

    If you decide to do this, this site will help you a lot.

  • Add a cutoff switch - by adding a latching (NON-momentary) SPST switch right after or before the momentary can give you a cutoff switch, which is useful during long breaks or to change guitars without a lot, or any, noise. This can just be placed on the hot wire, adjacent to the momentary.
  • Reduce the pop when pressing the switch - if you add resistors before and after the momentary switch, it will reduce the popping noise that is noticeable if you use the killswitch clean. Please refer to this short tutorial to learn how to do that.

Killswitch with LED

Killswitch with LED
Killswitch with LED

What Do You Think of This Project? - Any More Troubleshooting or Improvements I Should Include?

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    • profile image

      Shnake 5 months ago

      In the LED version of the cut off switch what size LED is best (I believe I have 5mm). Also, in this circuit is the light on or off when switch is stepped on.

      Instead of a battery can you use a 9v jack?

      Thank you!!!

      Shnake

    • profile image

      Martin Latino 17 months ago

      Agree, you need a N.O switch.

    • profile image

      Chris 2 years ago

      You have the switches listed wrong. You need a normally open switch for this to work. The Beavis diagram you included is correct (and it states you need a normally open switch). A normally closed switch completes the circuit and grounds out the signal until it is depressed, this opens the circuit and it functions as normal. The normally open switch only completes the circuit and grounds the signal when depressed (closing the circuit). Good tutorial, just has some information that needs to be corrected.

    • profile image

      jaysiggs 2 years ago

      Alright well looks like another project that didn't work. i did what you suggested and its still loud as ever and still only gets quiet when i touch the cables Fetty Wap Trap Queen Mp3 Download http://mp3goear.com/mp3/fetty-wap-trap-queen.html

    • chacks kovic profile image

      chacks kovic 3 years ago

      wow!! mind blown....you have struck gold do more of these please !!

    • jaysiggs profile image
      Author

      jaysiggs 4 years ago

      @pcmitchum: Not yet, I'm not sure what kind of pedal to post about. What would you like to see in a lens?

      Usually buffers, boosters, or distortions come next.

    • pcmitchum profile image

      pcmitchum 4 years ago

      Nice lens. Do you have anymore lenses about DIY guitar pedals?

    • EzLoanLookUp LM profile image

      EzLoanLookUp LM 4 years ago

      I installed a killswitch into my guitar a few years ago, but have rarely used it since. This is a nice tutorial for beginners to make a pedal!

    • profile image

      anonymous 4 years ago

      I am trying to build one with a LED and I can't really see the wiring diagram. It is a little fuzzy. Is there any way you could post a clearer picture or quickly run me through the LED build process.

    • jaysiggs profile image
      Author

      jaysiggs 5 years ago

      @anonymous: I'm sorry I couldn't have been of more help :/

    • profile image

      anonymous 5 years ago

      @jaysiggs: Alright well looks like another project that didn't work. i did what you suggested and its still loud as ever and still only gets quiet when i touch the cables. i put foil all over the inside, two layers. i soldered everything really well and made sure nothing touches. ill just call it quits and say thanks for the idea and ill save up for a real one later.

    • jaysiggs profile image
      Author

      jaysiggs 5 years ago

      @anonymous: I'm pretty sure it's a ground issue. Go with the foil (use any kind of tin foil or copper foil) and just line it one section at a time with either spray on adhesive or electrical tape. Take your time, and make sure you cover every side, even the bottom. It'll pay off. Good luck :)

    • profile image

      anonymous 5 years ago

      @jaysiggs: hey, yup using the spst switch, it is making a full switch when i press it, though i haven't soldered it yet that was my next plan. i have a go at the foil and see how that works. though on a side note the sound cleans up when i touch any of the guitar cables on the out side of the box and its loud again when i let go. thinking its the grounded issue?

    • jaysiggs profile image
      Author

      jaysiggs 5 years ago

      @anonymous: It could be a few things. Make sure you're pressing the switch down all the way, until you feel a click (try it with your hand first), sometimes if you don't push it down all the way it can make noise like that. Also, make sure you're grounding correctly. You're using an spst switch right? It only has 2 lugs (poles) coming out from the bottom to attach the wires to? If you have more than two poles, be sure to run the extra lug to ground. Hum can also occur if you haven't soldered it together. My best bet is with shielding though. If you haven't shielded it, you should do it. Just take regular tin foil and cover the inside of the pedal. This keeps radio, tv, and internet signals out of the loop that can cause hum. Let me know if it still doesn't work. Good luck!

    • profile image

      anonymous 5 years ago

      Hey, so ive made this pedal just as you have it here. it was easy and your photos really helped. though its very loud and i don't know why. i have checked all the wires to look just like yours. i have changed wires to more insulated and thicker, i have looked around online and can find no reason why there is a loud hum in both the "killed" and active modes. i don't have the led addition or any other modifications yet and i see how it should work but its still loud. any thoughts?

    • jaysiggs profile image
      Author

      jaysiggs 5 years ago

      @anonymous: smallbearelec.com and pedalpartsplus.com both have them. And yeah, I thought the diagrams would show up better but squidoo scales them down tremendously.

    • profile image

      anonymous 5 years ago

      @jaysiggs: Hey, nice addition of the diagrams. though they arnt the cleanest or most super technical, they work and that im thankful for. high five dude and let us know what else you've got. now the only issue im having with adding the led light is finding the dpdt switch or anything like it.

    • jaysiggs profile image
      Author

      jaysiggs 5 years ago

      @anonymous: There ya go :)

    • profile image

      anonymous 5 years ago

      Dude, this was easy and a cheep build. $14 rather than the $80 for pedals that do the same thing on amazon.com i found all the parts at my local radioshack and was done in about 30min. what else do you have to make???

    • jaysiggs profile image
      Author

      jaysiggs 5 years ago

      @anonymous: I'll get on that as soon as I can make a diagram, within the next week probably. I'll reply to your comment again to let you know when it's updated

    • profile image

      anonymous 5 years ago

      so how about that idea to add an led indicator light? id be interested in that too.

    • jaysiggs profile image
      Author

      jaysiggs 5 years ago

      @anonymous: You could make a volume pedal that steps down your volume when you activate it, that would be good for getting a clean sound on an overdriven amp if you don't use a distortion pedal. I use that one all the time. Jack > DPDT switch > 500k pot and a jumper for true bypass > Jack. I'll put something up on it. There's also a cool radio effect that I'm working on that would be passive, but I'm still working on it.