This is an easy to follow tutorial on how to build your own footcontroller for the Gibson Echoplex Digital Pro Plus (musical looper product). Since it is based on just some very few electronic components, this is actually more to show off how easy you can build your footcontroller that is solid and sturdy.
Step 1: Select Chassihousing or Existing Pedal to Modify
Here I choosed a couple of Fender pedals (footswitches for Fender amplifiers), because I got two (for free) that did not belong to any of the amps in the musicstore I work in. Actually a very good choice since it is very easy to modify these pedals and they are very sturdy. I had the luck to get my hands on two fourwayswitch pedals, but this mod apply to any of Fender footswitches (not those old egg models though!). These pedals exists in models from 1 switch up to 4 switches as far as I know (never seen five but maybe that exists too?). So you have the option to go a bit smaller if you want to by choosing perhaps two threewayswitches or one threeway and one fourway.
Start with demounting one of the black plastic sidepanels (which is mounted by four screws). The switches themselves are mounted on a steelpanel which you can slide in/out. You decide for yourself if you want to reuse this panel (you can flip it upside down if you don´t want that text visible). My choice fell on making my own panel since I´m going to mount two pedals together.
Step 2: Drill Some Holes, Somewhere...
As you will see when you have managed to rip out the Fender panels which holds all interior you will have a pretty sweet chassi to work on! Since I got two of these and want to mount them together later on, each unit is mirrored of the other one as you notice on which sidepanels I have removed here.
Next you have to drill a hole in one of the black plastic sidepanels for the mounting of an 1/4" phono jack. Then you will also need to drill some more holes somewhere, probably underneath the chassi if it doesn´t already exist. Which it doesn´t on the Fender pedals. The holes underneath are made so you can get the two units mounted together and in my case also for holding the... ehrm... PCB in place.
Step 3: Make Your Panel
Making your own panel is easy. Use the same width as on the Fender panels together. In my case since I am mounting my two pedals together, I choosed to make my panel in one piece. This will help making the unit as a whole a bit sturdier. Notice that I only made seven holes in my panel in contrary to the two Fender pedals (which were fourway switches each = eight holes). The Gibson Echoplex Digital Pro Plus footcontroller got the same amount of switches, and this unit is aimed to be (functionally) a copy of the original. I had to shift the position of the holes a bit to make the holes become even and goodlooking in respect of each other. Some simple maths could be good here to calculate the new positions. When done, you mount your switches on the panel.
Next it is time to make your... ehrm... (nonprinted) PCB. I use a sloppy piece of wood which is great because it will not give you any electrical shortcut by itself. My wiring is made of non-insulated copperwire which wired around nails of copper. Every wiring around each nail is also soldered.
The basics around this simple circuit for this pedal is read from a site called loopers-delight.com. For your convenience, I qoute them here:
"The circuit for a switch connected to the Footpedal jack is very simple. It is just a resistor and a momentary switch connected in series between the tip and sleeve of the jack. Pressing the switch connects the tip and sleeve together through the resistor. The resistor values determine the function that the Echoplex executes. These switches can be in parallel, although if you press several at once you will get unpredictable results."
Since these values are not exact I just took the closest one from the resistor E-series. Can´t remember if it were E12 or E24 though. The table of the expected values is provided here aswell, so you can go figure it out.
Step 4: Check Your Connections and Start Solder
Now it is time to doublecheck the pins of your switches so you know which pins you should solder at. The switches themselves are of the type called momentary (closing type), which means that these are only functional as long as you keep them pressed (think sustainpedal for piano). This means that only two of the three pins are the ones that you are interested in, and you need to find out which ones. This is done easy with a multimeter and using the beep function (that you will probably find in even the cheapiest multimeter). Determine which pins that will be in connection when the switches is pressed and solder your leads on these.
By looking at the images here you should be able to see how the "circuit" is realized. The Echoplex sends out an voltage which hits all these serially connected resistors, and it gets a lower voltage back depending on which switch you hit (and thereby are closing the circuit). Based on this the echoplex recognizes which function you are out after.
And as you already got your soldergun warm by now, you could go ahead and solder the 1/4" phonojack aswell.
Step 5: Slide It in Baby!
Time to slide the panel in into one of the chassihalves. Despite of the picture I took the right one first since the 1/4" inputjack will be mounted in the right one. Slide in your sloppy wood PCB in there too and mount it with screw. In my case I discovered that my piece of wood where not as wide as it should have been. So I had to fill out with some extra piece of wood since I don�t want the "PCB" to moving around inside the pedal.
Step 6: Watch Those Nails Darling!
When sliding the panel and your woody PCB into the chassi, you should keep your eyes open so that you will not get any shortcuts due to direct contact of those copper nails and the chassihousing. If any are at risk, bend them slightly toward the inner of the pedal. When done and you are fully in with the woody PCB and no nails are in shortcut with the housing, it is time to mount the inputjack onto that black plastic sidepanel. Check the pins of the inputjack so it will not touch any side of the housing or the panel that the switches themselves are mounted in.
Step 7: Close It Honey!
Well, only the other half of the chassi left to mount. Really easy. Slide the panel into it, watch the copper nails on that woody PCB (no shortcuts). Screw them together and see, there it is:
The Gibson Echoplex Digital Pro Plus Footcontroller!