In response to a recent comment I have provided the following layout for my pedal design for anyone interested.
I’m cheating on the pedal a bit and have no forward stop other than the actual potentiometer throw distance so there is the chance I could really do damage if I laid into a pedal. I had planned on adding stops at some point but just left it as is for now.
Here are some stats on the pedal layout
- Length: 11 5/8 inches
- Width: 3 1/2 inches
- Pivot Point: 3 3/4 inches from the heel of the pedal.
- The pin that holds the rack gear to the underside of the pedal is exactly 3 1/2 inches back from the toe.
- As far as placement of the mating gear to the potentiometer I basically placed it to meet the rack when the pedal was parallel with the deck. On my design this means the center point of the potentiometer is 1 1/4 inches from the underside of the pedal
- Back of pedal will rest on the deck in toe up position where the underside edge of the top is 2 1/8 inches above the deck
- In the toe down position the underside edge of the top stops at about 3/8 of an inch above the deck. A simple rubber footer would probably be an effective stop there.
Once you have everything assembled I would recommend sending the midi signal out to something like MIDIOX and testing the throw to find the zero point in the heel position.
One more quick post for the day. Awhile back I posted about a secondary pedalboard I had been working on. I completed it a few weeks ago and have been working out some kinks. Here’s a shot of ‘Constellation’ sitting in front of my original ‘BigFoot’ pedalboard. I’ll have a post about the construction and wiring of Constellation in the next few weeks and hopefully some audio samples showing off just exactly why I need all those blasted buttons.
This is just a quick post today… lots of things going on. Awhile back I finally got around to upgrading one mechanical aspect of my MIDI pedalboard. Originally I had used a piece of flat aluminum and a wire grommet to obtain a friction/pressure point against the back of the pedal gear rail. This was the original design…
The overall problem with this design was that it was either spot on perfect where it needed to be, or off a little and caused the pedal to drift. Under the weight of the pedal when flipped upright I would find that the gear would continue to rotate. In other words, the friction point where the wire grommet met the back of the gear rack wasn’t firmly mounted and couldn’t be adjusted. So after a few long walks through the local hardware store I came up with this little gem:
The new design is much better. What I’ve done here is mounted a 90 degree steel plate on the board then mounted the wire grommet against a screw with a lock nut. Then the screw is mounted to the steel plate with a set of lock nuts. With this design I was able to adjust the pressure of the wire grommet against the rack simply by altering the back lock nuts to reposition the screw. The pedals now stay in a fixed position when I lift my foot.
I was asked if there were any videos of the pedalboard in use. At the moment all I have is this older video of me noodling around with the system. The sound is from a room mic on the camera so it’s not the best quality but the video shows interaction between the board and DAW/VST.
So it’s been over a week since I posted about AmpliTube 3.5 and MIDI control. I had planned to post more sooner but my personal and professional to-do list just never stops. I wanted to do a little writeup on single-source multi-target control of AT3.5 (next post or so) but got a little distracted by all the other MIDI options within AT3.5 and the quick realization that I had no clue what half of this stuff was even for.
One aspect of my pedalboard are these two oddly placed switches kind of lower and between what would normally be bypass switches for the pedals.
My intention was to make these preset browsers but never tried to do so until this writeup. I have spent a lot of time in the MIDI Control Preset window where I never saw the option and obviously never really looked at the Global options. Getting to the Global options is simply a matter of clicking the MIDI button in AT3.5 then selecting the Global button in the top left corner.
I’m glad to see that AT3.5 has two specific pre-configured entires for preset changes. If you recall from my previous post “Quick Guide To Using External MIDI Controllers with AmpliTube 3” all I need to do is highlight the Preset Next entry, click Learn then tap the next button on my controller. Repeat for the previous button and we’re ready to change presets at the simple tap of a foot.
So next my eye is drawn to the Volume, Wah, and Wharmonator entries. Probably because I want to try and exploit them in unintended ways (it’s a personal tic). I can’t help but wonder what happens if I use two volume pedals in series? Ok sorta dumb I know, but what if I run a parallel config like signal chain 2 and have a pedal on each, what happens then? If I use two different Wahs, does it alter both? Let’s find out what’s going on here.
So after training the volume in signal chain one, anytime I drop a volume pedal, and regardless of which slot I move it to, the volume control just works. Pretty nifty. A huge time saver for a commonly used pedal. Dropping a second volume in-line defaults the control to the first volume in the series. That makes sense. Setting up a parallel config and placing a volume in stomp A and stomp B results in only the pedal in Stomp A responding to the controller. This makes a little less sense to me but I get it. Ok Wah time. I set the Wah row to learn in Global MIDI control and tap on a pedal. Good to go. Returning to the stomps I run the same tests as the volume and get the same results. I’m not terribly surprised to get the same results.
This all may sound like a bunch of overkill but I was just curious to learn the primary intent of the global ‘default’ controllers and now know it’s just for your first matching pedal in the chain (and behind the scenes AT3.5 scans Stomps A through B in slot order order making no distinctions between serial or parallel configs.) Obviously any deviations from this single pedal approach are best handled by MIDI Preset control setups as covered in the previous post but part of me wouldn’t mind a ‘cascading’ approach to control the first ‘non-bypassed’ Wah in the chain should I want to use two flavors in the same preset. Just a thought.
Here’s a quick breakdown of the pedalboard functionality:
- 1/4 inch input
- 1/4 inch TRS insert
- 1/4 inch output
- SPDT switch for selecting to enable the insert or not
- SPDT switch for defeating the input
- SPST momentary switch for temporarily stopping input until switch is released
- Audio taper potentiometer for volume pedal
Issues – I don’t know alot about passive analog circuitry but now know there is a huge difference in the selection of the potentiometer rating for the volume control. It’s currently a 10K pot when it should be a 250K instead… which is closer to what’s actually inside a guitar to begin with. An incorrect selection here degrades the power of the signal.
Potential Fix – Just replace the pot but I also like the degraded effect and will find a way to mimic the circuit path even with the new pot in place.
- 2 SPST Momentary switches intended for patch changes
- 6 SPST Momentary switches intended for bypass/defeat of the MIDI pedals
- 6 10K linear potentiometers for the MIDI pedals
- 1 Pitch bend/MOD wheel from a discarded Roland Keyboard controller
- 1 SPST Momentary switch for MIDI Panic/Reset
Issues - The only issue is the pitch bend wheel. It doesn’t allow for a full throw (not a physical limitation) and as such won’t transmit the full 0-127 MIDI data range. I can only assume the wheel had accessory circuitry to translate this properly.
Potential Fix - At some point I’m going to have to pull apart the wheel assembly and see if I can replace the potentiometer to the proper spec.
- 5 Pin MIDI In/Out
- 7-12V / 100mA DC Input
- SPDT switch for power enable/defeat
- LED for MIDI activity
Issues - None
I recently finished up the first part of a guitar pedalboard controller I’ve been planning/working on since about November of 2010.
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.
This is where I started design-wise in November of 2010:
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.
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.
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.
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.
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.
Finally, the end blocks were capped with an oak dowel and set screw.
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!)
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:
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.
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:
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.
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?
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.
Only three major tasks left in the construction phase.
I found an old modwheel while cleaning up… couldn’t resist. The handle is off an old sink. Why not? Looks great!
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.
Some of the things to point out in my 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.
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.
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!