Guitar Effects Pedal Building – Offboard Wiring Demystified

Probably the most complicated thing to grasp for first time builders is in regards to the offboard wiring.  Mark at tagboardeffects has a great explanation in his Offboard wiring page, but sometimes the generic board just isn’t enough.  After all, “Where do the potentiometers go?”, “How do I wire the ground wires?”, etc. just isn’t shown in the diagrams.  So I decided I would make a practical application showing a kit completely wired (minus the jacks) so you can see how it works.

UPDATE 11/17/2015

Check out our new 3PDT Footswitch PCB Circuit Boards to simplify offboard wiring and make wiring your 3PDT footswitch easier.

I chose the Dumbloid Special Clone Build I recently built since it has 4 potentiometers and a toggle switch.  It’s good and complex, so I figured it’d make for a good reference on this subject.

Guitar Effects Pedal Offboard Wiring demystified

 

The Veroboard Layout

The layout this is based off of can be found at http://tagboardeffects.blogspot.com/2014/03/shins-music-dumbloid-special.html, the version with clipping diodes.  It’s worth taking a look at the layout and seeing how it all matches up in this diagram.

The Splices

These aren’t required.  They mainly show how you can make the connections pretty much anywhere.  You can “daisy-chain” them, as shown with the ground on the 3PDT footswitch and the socket or you can make a joint like the wires going to the LED.

The 3PDT Footswitch Lug Orientation

In most cases, if the lug “blades” are horizontal, meaning the flat part of the solder lugs are horizontal, then it doesn’t matter which way it’s flipped around.  What happens inside the switch is it takes all of the middle lugs and switches them between the corresponding upper lugs or the corresponding bottom lugs.  It’s like 3 On-On toggle switches stacked side-by-side.  It’s still best to perform a continuity test just to make sure you have the switch correct before soldering the wires to the lugs.

The LED Wiring To The 3PDT Footswitch

Since most of us won’t be wiring the LED lead directly to the footswitch tab, I figured it might help to show it wired more remotely.  The resistor shown is a 2.2K Ohm carbon film, as per Mark’s diagram.  The resistor value can be as low as about 470 Ohms and higher.  The higher the resistance, the dimmer the LED will be.  A piece of heatshrink tubing is recommended to keep it from shorting out.

The Circuit Board Ground Wire

The ground wire for the circuit is wired to the switched lug just like the LED is.  If you’re not using a battery, then this isn’t important, but if you do install a battery, this “turns off” the circuit and keeps the battery from being drained.

The SPST Toggle Switch

The lugs on this one don’t matter as long as one wire is in the middle.

Adding A Battery Snap

Ok, so we sorta ran out of space and we don’t show a battery snap.  No worries, it’s pretty simple.  You’ll notice one lug on the DC Chassis Socket doesn’t have anything attached to it.  This is where you will attach the negative lead of your battery snap.  The positive lead will connect to the terminal the red wire is already connected to.  DO NOT connect the negative to the existing negative, otherwise you can cause your 9V battery to explode!

I hope this helps clarify things and if not, you can always give me a shout and I’ll try to help.

2 thoughts on “Guitar Effects Pedal Building – Offboard Wiring Demystified

  • January 24, 2016 at 8:12 AM
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    I think you need to revisit the wiring to the DC socket, if you connect the battery snap negative (black) lead to the lug you indicated it will short to the positive (red) lead of the circuit. In fact when there is no external power supply plugged in, the lug you connected the positive red lead to is internally connected to the lug you suggested connecting the battery negative to.

    Just to emphasize (so no one blows-up anything) these two lugs are for switching connection from the battery’s positive lead to the positive lead of the external power supply when it’s is plug inserted. The correct connection would be to switch the red lead (circuit’s positive) to the unused lug and connect the battery’s red lead that lug instead.

    Reply
    • January 26, 2016 at 5:42 PM
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      Hey Raghaven,
      According to the switched sockets like these that we sell, the diagram is correct. The lug that isn’t connected in this photo is the other “switched” lug, which it will switch between the lug that has the red wire and the one that isn’t connected. The center lug (or lug with the black wire) is never connected to either of these two lugs. Perhaps there are some other sockets that are configured differently, but the ones we sell are built in this way.
      The best bet is to always use a multimeter and test continuity to verify this is the case with their socket, especially if buying from another company. We can guarantee our sockets follow the above diagram, but we cannot speak for other vendors.

      Reply

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