General Guitar Gadgets is the best DIY stompbox site on the internet! We feature projects, kits and ready-to-solder PCBs.

There are many, many variations and ways to wire bypass switching and power connections. I will attempt to cover these variations on this page.

Let's start off with the power connections for your stompbox. The most common power connection for stompboxes is covered in this Power Switching Article

Here is a wiring diagram for a simple battery hookup

• Battery Power Hookup Diagram

Here's a wiring diagram for options of battery or DC jack power:

• Battery or DC Jack Power Hookup Diagram

The simplest form of bypass switching is a non-true bypass switching with a SPDT switch. This is used in a lot of the old stompboxes because SPDT switches were so much more inexpensive. Note that some designers put an input buffer outside the bypass so that the buffer was in your signal all the time and the "tone sucking" would be minimized. This is illustrated in the original schematic of the Blues Breaker.

• Non True Bypass with circuit input unbypassed
• Non True Bypass with circuit output unbypassed

Adding an LED to the non-true bypass switching requires a DPDT switch. Again, the input or output can be left in the signal path, depending on how you wire it up.

• Non True Bypass with LED, circuit input unbypassed
• Non True Bypass with LED, circuit output unbypassed

The simplest form of true bypass switching uses a DPDT switch. Here are two variations on DPDT true bypass switching.

• Standard True Bypass switching
• True Bypass with Circuit Input Grounding

It is possible to have true bypass switching with LED if you use some electronic switching for the LED indicator. This Ariticle from the GEOFEX site explains how this is done. Here's a wiring diagram for the Millenium 1 switching.

• GEOFEX Millenium 1 True Bypass switching

3PDT Switch

Here's the information on True Bypass Switching with LED indicator using a 3PDT switch. Here are some variations on 3PDT switching.

• True Bypass/LED indicator battery only
• True Bypass/LED indicator DC Jack
• True Bypass/LED indicator battery only, input grounded
• True Bypass/LED indicator DC Jack, input grounded

Note that R1 in these diagrams is a "current limiting" resistor for the LED. The value of this resistor will vary depending on the type of LED used and how bright you want the LED to be. The value of R1 is generally between 1k and 8k2, typically 4k7.

3PDT Switch Positive Ground Circuits

Here are some variations of wiring PNP Positive Ground circuits with a 3PDT switch. The basic information about this can be found in Power Switching Article in the Tech Pages.

• True Bypass/LED indicator DC Jack For a PNP Positive Ground Circuit
• True Bypass/LED indicator DC Jack Input Grounded For a PNP Positive Ground Circuit
• True Bypass/LED indicator DC Jack For a PNP Positive Ground Circuit With a Positive-tip Power supply. This is the way the Fulltone PNP stompboxes are done. Not Recommended by us since you will need to have a different wiring for your wall wart.

Here is a diagram for switching with 2 effects in one box using 3PDT and LED indicators

• Two Effects in one box, True Bypass/LED indicators DC Jack, inputs grounded

Now that we have most of the variations covered. Lets look at how to use these diagrams in the projects on this site. Here are the steps to take:

1. Print out the switching diagram that you want to use for your project.
2. Print out the wiring diagram for the project your are building.
3. Identify the Circuit board input and Circuit board output for the project circuit board. Note that many times the circuit output is acutally the middle lug of the volume potentiometer.
4. Use the print out of the diagram to hook it all up, ignore the wiring on the project wiring diagram if you are using another variation.

I regret that I cannot provide diagrams for each variation for each project on the site, but this is about the best I can do.