This post may get scrapped at some point in time, but in the meantime...
Here's how to make yourself an easy testing rig! I built a new one for myself recently and decided to take a pair of pictures of the process.
Because the mantra of the tech helpers is "rock it before you box it" (meaning that you should always test your circuit board BEFORE you actually go about wiring your pedal inside an enclosure), a testing rig is one of the best ways to go about ensuring your pedal works properly. There are a number of different ways to do so, but this is the way I prefer. It's simple, it works, and it's incredibly helpful for ensuring things don't get hairy after you've spent 2 hours wiring your pedal together only to find out something doesn't work. If you "rock it before you box it" you will KNOW that it's the not the circuit board that's the problem, it's the wiring. Right?
*BONUS* I built my rig with an BUILT IN SIGNAL PROBE! You do not have to do this as well, it is entirely optional. I built it into mine so it will function in a dual purpose for me, both being my board tester and a debugging too. Any time you see these ** remember that this has to do with the OPTIONAL signal tester.
So first off - what do you need to build one? Well, in the least you will need:
1x enclosure (I used a 125 B, but a 1590B/1590NS/1590BB or any number of enclosures will work)
2x mono jacks (I used open frame mono switchcraft style ones)
1x DC Jack (isolated is important)
2-4x Alligator clip cords (2 if you don't mind having some identical colours, 4 if you need different colours. 4 is much better)
*1x 0.1uF Film Cap (important for an audio probe)*
*1x multimeter test lead (This is your probe)*
First off, you'll have to drill your enclosure. I used an enclosure that had a former life as a headphone amp for me. I cannibalized it for my breadboard rig (another upcoming post... I hope), and I had no use for the funny way I had drilled I used it before. Fortunately, I thought up this project. Anyway, as I was saying - you will need to have holes for the DC Jack, and the two 1/4" jacks for sure, and my enclosure has those holes at the 'end' of the enclosure. Next you will need at least one hole for your alligator clips *and audio probe* to come out of the enclosure. You can have them all come out of one hole, or you can have them all come out of individual holes, it's up to you. I already had two holes to use, so I used them.
After that, you need to cut all your alligator clip cords. I cut mine in half, and it gave me lots of cord to work with. This is where colour options come in. Obviously, you should use the colours that make the most sense to you, but if you need to, you can use all of one colour and then find a way to label all the alligator clips so you know which one is which. You will ultimately end up with 4 alligator clips: power, ground, input and output.
Next up you will need to begin to work on the wiring (Refer to the picture below for stuff in brackets). The DC Jack ground connects to one of the jack's sleeves (green wire). The DC Jack's power out connects to an alligator clip (Red wire). Now attach another alligator clip to ground (white wire). Next, you will need to attach another alligator clip to the input jack's tip (yellow wire) and then finally, you'll need to attach another alligator clip to the output jack tip (black wire). *To include an Audio Probe, you will also need to attach your Film Cap to the output jack tip also. Then you will attach your probe cord to the other end of the film cap.* Check out this picture for my finished version! Note that the zipties are for anchoring my cords. You do not have to do this, but I did it to prevent the soldered ends of the cords from becoming weakened by my yanking on them.
And here's the finished product! When I want to use this, I hook up the yellow wire to the input of my circuit board, the red to the board's +9v in, the black to the board's output, and the white to the board's ground. *To use the probe, I would leave the output alligator clip attached to the board, but I can now use the probe to 'preempt' the output alligator clip. Now the probe will allow you to find where there is active signal. This is especially helpful for both debugging a non working circuit, and for calibrating some circuits like delays. I recommend everyone have some sort of probe to use, whether or not it's built into a testing rig like this is up to you!*
^Please note, I'm hoping Brian will find the spare time to make up a 'madbean approved' wiring diagram for this, stay tuned if the description and picture isn't enough!^
Jacob
