AmpliTube Guitar MIDI Pedalboard Project

I recently finished up the first part of a guitar pedalboard controller I’ve been planning/working on since about November of 2010.

Completed Guitar Pedalboard
Completed Guitar Pedalboard

Keep in mind that I never really intended to post a How-To/DIY on this project and because of that I’m missing various details on how some things were done. At a certain point I just started photographing everything as I progressed. Overall there are plenty of photos and descriptive info to foster ideas if this is something you want to take on. My only advice is to take your dear sweet time. This was just about the most challenging project I’ve taken on in the past few years and is evidenced by the 6-7 months of development it took to get to where I am today. That said… it passed the all important “smoke test” the first time I plugged it in, so taking your time on this stuff is a good thing.

The purpose of the pedalboard is to send MIDI messages to my Presonus Studio One digital audio workstation running AmpliTube 3 from IK Multimedia. AmpliTube can receive MIDI commands to turn on and off guitar pedals and alter parameters like volume, gain, wah-wah pedal filters, etc.  There are plenty of midi controller pedals out there (IK even makes a line) but with what I wanted I knew I would end up in a wiring mess and alot deeper in the hole cash-wise for this adventure. Since I only play in my studio I wasn’t overly concerned with building the pedalboard like a tank, I just focused on good design and general ruggedness.

My first stop was trying to figure out how to even tackle the electronics aspect of this. I asked a horde of music hardware vendors if anyone made some kind of black box you just plug a bunch of expression pedals into and then it all runs to a simple MIDI output. To my knowledge, nobody (commercially) makes such a simple little beasty. Pressing on I got into the idea, and alluring underworld,  of DIY MIDI… USB controllers using joysticks, programming your own joystick to MIDI drivers, etc. All way too much for something I just wanted to have fun with.

After alot of searching I finally discovered Doepfer Electronics in Germany, producers of MIDI keyboards/controllers galore and one great lineup of OEM/DIY controllers. They have plenty of them to choose from but ultimately I selected the Pocket Electronic as it offered up to 16 buttons or Potentiometers (sliders/pedals) running a MIDI in/out pair (which could be daisy chained)… just enough for the design I had in mind. I got the board from Doepfer’s US Distributor, Analogue Haven, based in California.

Pocket Electronic
Pocket Electronic

This is where I started design-wise in November of 2010:

Guitar Pedalboard Design
Guitar Pedalboard Design

The original design (sorry, not alot of light near the whiteboard) was to include 1 analog pedal with an insert, 5 midi pedals, and an array of switches to send signals, reverse pedal polarity (up becomes down), etc. The pedals were shaped like feet and all of the wiring was to run out of the back of the unit.

Early Prototype
Early Prototype

This early prototype of a pedal was tossed together by myself and my good friend Jeff. I traced my Cons and we used whatever was in the garage to toss together the initial concept. If I remember correctly the first pedal was the rack and pinion from a telescope, curtain rod, potentiometer, a bracket from those western-style swinging doors, and some screws/plastic tubes and brackets. Crazy… but it worked long enough to give me hope, then it broke. Good enough.

The first thing I struggled with were the mechanics of the pedal itself.. specifically the issue was driving the potentiometer via the pedal. I went through a few designs then ultimately opened up my old Roland volume pedal (uses a sliding mechanism) and then the Crybaby Wah pedal (uses a rack and gear assembly). Preferring the Crybaby engineering because it seemed a little simpler to engineer, I was set. Finding a source for the Crybaby parts took some time but I was very happy with the service from NewOldSounds.com. I ordered a set of racks and gears then played the waiting on shipping game.

Pedal Design
Pedal Design

The pedals were the first thing I built. Ignore the nails and gizmos all around the above image… we’ll get to that later. The pedals are simply just 3 inch wide oak from Lowe’s. I cut two three foot sections into foot long pieces then routed off the sharp edges with a 45% bit.

Near the top of the pedal you can see the pedal racks. I cut then filed pieces of aluminum channel (again Lowe’s), added a hole for the rack pin, then screwed them to the board and mounted the rack via the pin insert.

The pivot point of the pedal is a really crazy design but this is what happens when you start with one thing, get too far in, and have to make it work. The base of the assembly is aluminum channel which is screwed to the board with countersunk nuts on the top of the pedal. Within the channel (at the ends) you can see nylon grommets which have been cut to fit inside the channel. Through the grommets is a length of 1/4 aluminum rod. The rod has a setscrew which keeps it from pivoting in the grommets. Working our way out you will find a 1/4 washer, 1/4 clear tubing to help pressure fit the pedals together, another 1/4 washer, then finally a 1 inch nylon grommet. I can probably imagine nine better ways to do this now … live and learn.

Mounting Layout
Mounting Layout

Back to the nails. The blocks are oak which has had holes (the same size and the nylon bushings) drilled through them at a 90 degree angle then four mounting holes at the corners of the blocks. They were all placed on a curtain rod then run through the table saw to give them the angled edges. The pedals were then placed on the pedalboard at even intervals and the blocks spaced between the pedals. The nails were simply tapped in to provide marks ensuring a proper lineup for each block when I drilled the mounting holes.

Mounting Holes Revealed
Mounting Holes Revealed

Holes were then drilled in the board then working left to right, each block was temporarily mounted followed by a pedal until all blocks were in place. No photos exist of this, but obviously I put some non-skid tape on the pedal faces. This is just the standard black no-skid stuff you can get at Lowe’s.

Pedals Temporarily Mounted
Pedals Temporarily Mounted

Finally, the end blocks were capped with an oak dowel and set screw.

End Block
End Block

Now to backtrack for a moment. You may remember that oddball pedal design and mention of some clear tubing. The reason for the tubing is to allow for adjustments in the placement of the pedals so they glide effortlessly between the blocks without touching. There was alot of troubleshooting to get that to work. Basically if the left side of a pedal was rubbing the block, I needed to pull everything and put a longer spacer. Then that may change the pedal next to it, and so on. So this was a tedious chore to finalize and one day I’ll change the design, but it works now and that’s enough for me.

After the pedals were working well I marked the location of each rack gear, labeled each pedal and block, then pulled the whole thing apart (again… this design will never be repeated!)

Marked Locations for Gear Area
Marked Locations for Gear Area

Ok so on to the gear and potentiometer. The Crybaby Wah pedal has the rack gear as shown earlier which marries up at a 90 degree angle to a gear on a potentiometer. I needed to find a way to mount the potentiometer, keep it from rotating, and also take a little abuse from the constant up-down action of the gear. So here is what I came up with:

Potentiometer Assembly
Potentiometer Assembly

The frame is 90 degree aluminum stock with a mounting hole and (to the right) a ‘stop hole’ for the little tab that sticks out on potentiometers. This holds the pot in place without rotation. The potentiometers were 2 inches long and here is where I got fancy. It’s hard to see in these photos but there are two problems with standard potentiometers and the Dunlop replacement parts. First, the gear has a very shallow D shape that is not common and second, there is a snap ring on the end. I don’t  know how I decided to do it this way, but before assembly I put the potentiometer in my drill press, just like it was a bit then threw the switch. Using a hacksaw I was able to cut a thin notch for the snap ring. I then raised the blade about 1/8th of an inch and cut a little deeper to score a cutoff for the post.

Once the post was cut off I then filed the rough end and while in a vise, carefully filed just enough of the rounded post off to form the shallow D to mate with the gear. Then I did that whole process over and over for the rest of the pots.

Nothing Quite Like Garage Machining
Nothing Quite Like Garage Machining

It was time to mount the potentiometer assembly. Using my marks from before I measured the space needed for the gear and 90 degree angles then knocked this out with a jigsaw:

Potentiometer Mounting Hole
Potentiometer Mounting Hole

The left side is for the pot body, the slots are for the 90 angle facing and the open area is for the gear. Using the 90 degree stock and this ‘slot’ allowed for a good bit of contact surface area and added strength.

The Potentiometer Assembly Just Slides Right In
The Potentiometer Assembly Just Slides Right In
Underside Shot Of The Rack Mated To The Gear
Underside Shot Of The Rack Mated To The Gear
All Pots In Place
All Pots In Place

After cutting then staining the board and pedals, the assemblies were screwed into place followed by remounting the pedals. Starting to look like something, isn’t it?

Assembled Pedals
Assembled Pedals

In order to hold the rack against the gear, and to keep the pedal positioned when your foot is taken off, Dunlop uses a greased wire grommet pushing up against the back of the rack. Ok… good enough for me.

Wire Grommet Mounted to Stock Aluminum
Wire Grommet Mounted to Stock Aluminum

Only three major tasks left in the construction phase.

Angled Housing Box Built Around Board
Angled Housing Box Built Around Board

I found an old modwheel while cleaning up… couldn’t resist. The handle is off an old sink. Why not? Looks great!

Mod Wheel
Mod Wheel
Footswitches Added
Footswitches Added

I added a series of footswitches for various purposes that I’ll outline later. Some momentary, some on/off. I got all the switches from AllElectronics.com. For whatever reason these footswitches vary wildly on price and All Electronics seemed to have the best deal and their site gave me the most confidence. I also got the 5 PIN din plugs and 1/4 inch jacks through them.

This is where things in this post will speed up. Wiring this beast took about 2 days and if you want to learn about that, opt for reading the manual with the board. Instead of soldering  to the ribbon cables that connected to the board I opted to use a series of terminal strips. My thinking was that I’ve never done this before and I didn’t want to have to undo alot of stuff if I made mistakes. This turned out to be a wise choice as I made about a half dozen mistakes that were easily corrected by unscrewing a few terminals and switching wires.

Wireapalooza In Effect
Wireapalooza In Effect

Some of the things to point out in my wiring:

Audio Wiring
Audio Wiring

The first pedal is an audio pedal and serves as a passive volume control. There are three audio jacks for in, out and insert in the chain. there is an a/b switch for the insert along with a master kill switch and a momentary kill switch for stutter effects or just temporarily muting the line. The exposed copper wire feeds through all the pot mounts and is grounded to the MIDI board as well. I’m currently using a pretty mismatched pot for the audio. It is degrading the signal but in a way I like. It almost gives my guitar a semi-weak vintage pickup sound. I trying to figure out a way to allow that with an upgrade potentiometer before I change it. If I need to hot-rod the guitar I currently just run it right to the audio input of the DAW.

Midi And Power Hookups
Midi And Power Hookups

Another early design decision was to put all the inputs on top of the pedalboard. I decided to also run two cropped MIDI cables to 5 Pin DIN connectors instead of mounting the board in such a way to allow direct plug in of the cables. I did this for two reasons. First, I didn’t want to break the board with general wear and tear plugging in cables and second, since multiple OEM units from the vendor can be daisy chained, this design allowed room for a second board and easy connectivity. In this show you may also be able to see the MIDI panic button near the DIN plugs. There is also a power switch just to the opt out of view.

The Final Board
The Final Board

And there you have it. One 6 month long, but worth it, ordeal. I’ll be posting some follow up videos on how the board interacts with AmpliTube 3 along with an overview of the various board functions.

Go forth and create!

15 thoughts on “AmpliTube Guitar MIDI Pedalboard Project

  1. Very nice ! Congratulations.

    I have also the same idea , that’s why I have a little question to ask about the Pocket Electronic product.
    I need one Pocket Electronic because I only want to plug a few ( two or three ) expression pedal on it, but I’ve read in the manual this :

    • Do not power on PE (i.e. do not connect the power supply to the corresponding jack socket) before all 16 analog inputs are connected. Do not leave analog inputs unconnected !

    Does it means that I have to use all of the 16 analog input to be allowed to use it? Since, I only want to plug only a few sensors, Is this product is fine for my use? I am not an electronic professional, so any help or advice are welcome.

    Sorry for my english, and thanks in advance for your answer.

    Like

    1. Dge,

      You will not have to use all of the inputs but the circuits for any unused inputs will have to be connected to GND. This ensures that a midi data of 0 is established for that particular input controller so no random data is transferred.

      Charles

      Like

  2. hello!
    I`m from Brazil, and I want to know where you bought this midi pocket eletronic. I’m not finding a on line store to buy one. If it’s possible, can you send me some links where I could find this pocket eletronic midi board.. ? and how much it cousts to you there…

    I am very interested to build a midi controller like this. I’m trying to configure a ps2 controller as pedal with another tutorial, but isn’t working im my pc…

    thanks for help!

    Like

  3. Dude this is the sickest thing I’ve seen in a while! Well done!

    I’m also in the process of building a midi controlled board, but mainly to switch pedals, rather than to control midi functions. I’m using the PedalSync products but I’m going to go look at the Pocket Electronic now.

    Again, well done! Woodwork looks top-notch!
    You should be very proud!

    Like

    1. Thanks mucho. I have an upgrade post coming soon for the audio portion followed by a post for a 32 button / 4 pedal upgrade for the midi portion. If all goes well there will also be a pretty slick Dunlop wah mod post… Maybe by next week.

      Like

  4. Hello!

    Killer project!!! Did I read correctly that you purchased the gear and racks that are used with Dunlop wah/volume pedals by themselves? I went to the website you had the link for and I don’t see this as an option anywhere on their site….I don’t want the potentiometer part just the gear and rack.

    Thanks very much!

    Jim

    Like

    1. Thanks Jim… it’s still running strong to this day. I have a post coming soon about an upgrade I made to the wire harness used as a friction pusher against the back of the rack. It’s now fully adjustable.

      Anyway… to answer your direct question, New Old Sounds definitely has the gears and racks in stock. Here are the links:

      Gear (Black)
      http://www.newoldsounds.com/index.php?main_page=product_info&cPath=128_318_323&products_id=792

      Rack (Black)
      http://www.newoldsounds.com/index.php?main_page=product_info&cPath=128_318_323&products_id=790

      Let me know if you have any other questions.

      Like

  5. Hey
    Your project is truly inspiring.
    I’ve seen a lot of projects that show how to build your own MIDI controller pedal by using your old wah chassis, but I was not intrested in that.
    So your tutorial for bulding a pedal system from scratch is perfect!

    Thou if it wouldnt be too much to ask, I would like to know the measurements of the wah controller (Width/Lenght), the position of the rack gear/pivot point and if you press the wah pedal all the way open, so that the back touches the ground, then how high does the other end stand from the controller surface.

    Also for other people building this beast, You can probably replace the rack gear original pieces with lego technics rack gears, which are cheaper and available on eBay.
    They just require some drilling.
    And Doepfer can be replaced with an Arduino (or it’s Chinese ripoff brother, the “Funduino”)
    Mega board.
    (I study economics, so I pretty much study how to optimize costs)

    Thank you for the project and info, should you get the time to answer me.
    Greets from Estonia

    Like

    1. Sten,

      Thanks for the comments. I have added a new post in relation to the pedal design that I hope helps:

      https://charlesrthompson.wordpress.com/2013/04/23/midi-pedalboard-pedal-design/

      I really don’t know much on the lego technics gears and went close to the design of the Dunlop method simply because it has worked for so many for so many years.

      I’m poked around with Arduino and see it has some MIDI libraries but I went for the lazy approach with a ready-to-roll board. Will be interesting to see what you come up with.

      Good luck,

      Charles

      Like

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