Eoo3: Programmable Looper/Switcher/Midi Controller

[Marshall Arts]

This is basically an arduino looper for eight loops with the ability to store 12 presets. It can also be used to switch up to 4 amp functions (required for my Engl Ironball). For another amp (Marshall 2554), I needed an additional switch to change the polarity of one of the switches (so the LED is lit, if the hot channel of that amp is activated).

Anyway, I built it already in 2015, resurrected it today from the basement and shockingly found out that I never labelled it, so I had to reverse engineer what the 6 mini switches, 17 footswitches and 14 jacks were for. So, the only reasons to post it now is twofold:

• I think, it got lost in a forum crash years ago.
• Remember to label in time, if you ever build something that big.

Eye-candy:






...and the way it looks today:

[brejna]

Ahahahaha! Awesome! I am looking at the pcbs I got from you and I was thinking there is no way will finish this.. And you post it right now..

[Marshall Arts]

Ahahahaha! Awesome! I am looking at the pcbs I got from you and I was thinking there is no way will finish this.. And you post it right now..

Brenja ! At least I can say that it works perfectly even yrs after building it. Like your voodoo vibe...

[gordo]

Mine's about 90% done.  Hopefully this pushes me to finish it.

[madbean]

Damn, I need this in my life

[jjjimi84]

Yep that is amazing!

[pickdropper]

Damn, I need this in my life

Me too.  What a fantastic job.

[cooder]

Totally amazeballs! 

[brejna]

Ahahahaha! Awesome! I am looking at the pcbs I got from you and I was thinking there is no way will finish this.. And you post it right now..

Brenja ! At least I can say that it works perfectly even yrs after building it. Like your voodoo vibe...

This is great project.. Is this suppose to be 14 preset looper?

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

[Marshall Arts]

Ahahahaha! Awesome! I am looking at the pcbs I got from you and I was thinking there is no way will finish this.. And you post it right now..

Brenja ! At least I can say that it works perfectly even yrs after building it. Like your voodoo vibe...

This is great project.. Is this suppose to be 14 preset looper?

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

Yes, it can do 14 presets, but on mine, I sacrificed one button, so MINE is 12 presets only. Will use the lower left button for a taprecise board.

[brejna]

Ahahahaha! Awesome! I am looking at the pcbs I got from you and I was thinking there is no way will finish this.. And you post it right now..

Brenja ! At least I can say that it works perfectly even yrs after building it. Like your voodoo vibe...

This is great project.. Is this suppose to be 14 preset looper?

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

Yes, it can do 14 presets, but on mine, I sacrificed one button, so MINE is 12 presets only. Will use the lower left button for a taprecise board.

I get it.. I will probably start working on it. Only thing I cannot decide what do with is enclosure..

P.S. Probably everyone are expecting another run of pcbs and chips..

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

[Marshall Arts]

Ahahahaha! Awesome! I am looking at the pcbs I got from you and I was thinking there is no way will finish this.. And you post it right now..

Brenja ! At least I can say that it works perfectly even yrs after building it. Like your voodoo vibe...

This is great project.. Is this suppose to be 14 preset looper?

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

Yes, it can do 14 presets, but on mine, I sacrificed one button, so MINE is 12 presets only. Will use the lower left button for a taprecise board.

I get it.. I will probably start working on it. Only thing I cannot decide what do with is enclosure..

P.S. Probably everyone are expecting another run of pcbs and chips..

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

You should get the blocan enclosure, it's worth it. Check the build doc for details...

I would create a new version of the relay board, if I ever find time. I made it with fritzing (!), meanwhile I know how to work with eagle. Fix some minor issues, but God knows when I find time...

[Marshall Arts]

For the enclosure:

http://www.rk-rose-
krieger.com/fileadmin/catalogue/neuheiten/news_kabelkanalsystem_gb.pdf

[brejna]

Ahahahaha! Awesome! I am looking at the pcbs I got from you and I was thinking there is no way will finish this.. And you post it right now..

Brenja ! At least I can say that it works perfectly even yrs after building it. Like your voodoo vibe...

This is great project.. Is this suppose to be 14 preset looper?

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

Yes, it can do 14 presets, but on mine, I sacrificed one button, so MINE is 12 presets only. Will use the lower left button for a taprecise board.

I get it.. I will probably start working on it. Only thing I cannot decide what do with is enclosure..

P.S. Probably everyone are expecting another run of pcbs and chips..

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

You should get the blocan enclosure, it's worth it. Check the build doc for details...

I would create a new version of the relay board, if I ever find time. I made it with fritzing (!), meanwhile I know how to work with eagle. Fix some minor issues, but God knows when I find time...

Your build is in 80cm long enclosure, right?

Whenever you find time to make another batch, count me in..

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

[Marshall Arts]

It's actually 60.5 mm long. I will see, if I find the time for a new release. Changes would be:

- Relay board:
-- Move Cable connections to the side of the board, that points toward the inside of the enclosure
-- Create an eagle component, that allows for easy shielded wire connection (basically a hole to push the cable through, with a solder pad for the shield and another solder pad next to that for the inner wire)
-- Correct missing ground connections (result of a bug in fritzing)
-- Improve ground plane (Version 1 has ground fill, but eagle can do this much better than fritzing)

- Control board:
-- Add space for blocking caps
-- change design to load a complete nano (like I have done on my moebius controller and my taprecise design) - they are dead cheap these days and come with an USB port, so people can program their own software, update easily etc. Plus, I dont have to program and ship them.
-- use internal pullup resistors in the Atmel processor (and get rid of the 17 10k resistors) - this requires inversion of the switch logic in the program code, though...
-- Correct missing ground connections (result of a bug in fritzing)
-- Improve ground plane (Version 1 has ground fill, but eagle can do this much better than fritzing)
-- Add a Midi-Port. It's not hard to do in Arduino to send out static Midi program changes on events. And I might want to add a Line6 HX Stomp to my board somewhen in the near future...

Other:
- Change drill template, so the jacks are more far away from the relays
- Add little board for footswitches and LED
- Add a solid-state-relay based mute function (mute the output for 10 ms while switching)
- Add a third bank and a tri-color-LED for a total of 21 presets
- Skip the "Write" button. Store presets by holding respective program button down for three seconds. Downside: Program change will happen on the release of a button (because only then the system will know, that the button has not been pressed long). Alternative: Enter write mode by holding down the bank switch for three seconds.
- Add an input buffer
- Enhance one or two loops with a "trails" feature (for delays or reverbs), with phase invert option.
- Add a Tuner out/Mute button
- Bypassable, galvanic separation of Loop 7 or 8 for use with two amps
- Move Jacks for Input, send, return and output to the (audio) side of the looper (adjust the audio PCB accordingly). Depending on how you build it, this could be either left or right. Potentially reduces the need for an additional patchbay on the board.
- Mute on Tap Tempo Longpress
- external access to usb port

I should mention, that none of these is crucial and that version 1 works very well.