Eoo3: Programmable Looper/Switcher/Midi Controller

[Marshall Arts]

Damn, I need this in my life

Brian, as I saw somewhere else that you are rebuilding your board - when do you need the V.II of this? I would be honored.

For the impatient ones: Doc for Version I: https://drive.google.com/file/d/0B5vtgOg9bRJjeW0xV0Q4YlFOVU0/view?usp=sharing

[madbean]

Damn, I need this in my life

Brian, as I saw somewhere else that you are rebuilding your board - when do you need the V.II of this? I would be honored.

For the impatient ones: Doc for Version I: https://drive.google.com/file/d/0B5vtgOg9bRJjeW0xV0Q4YlFOVU0/view?usp=sharing

Sorry - I ran out of time to respond to your PM yesterday. I plan on building a couple loopers but I haven't decided what will go on the new board yet. I'm gonna build Jacob's Epic Looper and I'm definitely interested in building whatever you come up with. Ideally, what I want is pretty much the Boss ES-8 but I know that's probably beyond DIY. The thing that appeals to me the most about that one is the ability to re-order pedals, parallel loops and (very importantly) a couple stereo loops with Midi capability. It seems the best way to control this behemoth of a board I'm building and control it in a straight-forward way.

So, I'm not really on a time-frame. It'll be a couple months before I build the actual pedalboard itself. The project doesn't need to be completed until next summer (which I'm hoping when the new record gets started on). In any case, whatever you come up with I'm going to want to do

[Marshall Arts]

Cool, thanks. I just checked the Boss Looper, that thing is way beyond DIY, I agree (that's why it comes with a pricetag as well...). But it raises a question, that maybe somebody has an answer to:

Changing the order of 8 loops cannot be done with a reasonable amount of relays, but it says it is an analog circuit. So, how do you think they do that?

[Marshall Arts]

Just spent some time for research... An audio analog multiplexer would be required... Well... 8 of them...

[Marshall Arts]

Just spent some time for research... An audio analog multiplexer would be required... Well... 8 of them...

Even better: They sell Audio switching matrix IC, controllable via I2C. ADG2128 or similar. I just don't have time to deal with that and my analog knowledge and equipment (oscilloscope) would not be sufficient anyway. But given the use cases in the specs, this would be the magic ingredient for arduino controlled pedal order switching. Add a digital volume control IC, and you get closer to what the Boss unit can do...

[Marshall Arts]

In order to motivate myself, I ordered a Line6 HX Stomp :-). Plan to get midi tap tempo working with the next release. Any other midi stuff I should be aware of? Haven't used midi all that much...

[Aristatertotle]

That's awesome. I'm considering an HX stomp, and the upgrades you're doing make me want to not build v1 and wait for v2 of the Linda.

I think another useful button could be the midi control to turn on/off the tuner screen on the HX stomp.

[cooder]

In order to motivate myself, I ordered a Line6 HX Stomp :-). Plan to get midi tap tempo working with the next release. Any other midi stuff I should be aware of? Haven't used midi all that much...

Very very cool!
Also let us know how you like the Line6 HX stomp, looks like a clever device that runs in the face of things like Eventide H9 and the like. Wondering how you like the sounds and general useability... review pleeeease.

[brejna]

Is it possible to add midi pc and cc messages? Also if you could design it to choose midi channel of each message, that would be awesome..

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

[Marshall Arts]

Is it possible to add midi pc and cc messages? Also if you could design it to choose midi channel of each message, that would be awesome..

Poslano sa mog Redmi Note 6 Pro koristeći Tapatalk

PC messages should work, but CC... I would have to provide an extra jack for a wah/volume-style pedal to create the CC messages. I am not sure, if that would work flawlessly (havent worked with interrupts on Arduino yet...). Midi channel would only be assignable globally, I am afraid. I don't want to add a display and editing that without a display would be tricky...

[kaeisy]

PC messages would be a great feature. Looking forward to build the lopper/ switcher someday.
I hope this project won´t be killed by too much options, like other promising projects before.

[Marshall Arts]

I am still working on this monster, although I am really distracted by the arrival of my Line6 HX Stomp ;-)

Most difficult thing is to create space for the relay board. With the current jack placement (see picture 1 below), I am restricted to 5 cm in depth, and with the pricing for PCB manufacturers, I don't want exceed 10 cm in length. This doesnt leave any room for mounting holes (which I need)

I want to move the connections for the loop jacks to the inward facing part of the PCB and that creates a lot of vias (which I dont want). It's necessary, though, as with the old design, I had to use a vero PCB to connect the audio pads to the jacks (see picture 2 below).

So, I am planning to move the input an output jack to the left side (!) of the enclosure, move all the switches to the very right side (close to the control board) and also move the two amp-switching jacks tho the right side. The send and return jacks will have to be arranged above each other to create even more space (with the I/O jacks on the left side, the board needs to move to the right...).

Large enclosure, still space issues :-)

With all this work, it would be great to find out, if the US-based distributor for the BLOCAN Aluminum Cable Channel (Phoenix Mecano, https://www.phoenixmecano.com/products/mechanical-components/aluminum-cable-channel/) can cut 60 cm pieces and ship them for acceptable prices within North America. I will send them an email to find out.


Picture 1:


Picture 2:


Here is a picture of the current design with three mounting holes...

[madbean]

Most difficult thing is to create space for the relay board. With the current jack placement (see picture 1 below), I am restricted to 5 cm in depth, and with the pricing for PCB manufacturers, I don't want exceed 10 cm in length. This doesnt leave any room for mounting holes (which I need)

[Marshall Arts]

Thanks for the hint, BUT: I decided for the Amp-Style jacks, because

- they are automatically bypassed, when nothing is inserted. So, your sound is not muted, when you engage an empty loop.
- they are insulated from the grounded enclosure. Might help with fixing ground loop issues, should they occur.
- I already used TRS-Jacks and you need y-cables for the loops. I might reduce the number of jacks by one, if I use a TRS for the "floating send/return" as well. I want to stick with TS Jacks for Input and Output (and might use the Lumbergs for them :-))

[Marshall Arts]

Is it possible to add midi pc and cc messages? Also if you could design it to choose midi channel of each message, that would be awesome..

Sorry, my answer was not correct: Yesterday, I worked with my new HX stomp and tried to find out how to make presets, snapshots and midi-controlled bypass functions work for me. Obviously, I did not know enough about midi so far, as I always thought that CC messages were for continous controls only (pitch bend, modulation, ...). Here is what I found out and as a result, how I think I will implement midi into the Looper:

The HX Stomp (and presumably other Midi-Devices as well) is surprisingly static in terms of which PC/CC messages it expects to perform specific functions. Snapshot changes will always be done with CC 69 and value 0 (Snapshot 1), 1 (Snapshot 2) and 2 (snapshot 3).

Bypassing Blocks is more flexible (HX can be teached), but some CCs are system reserved.

As I guess, that this is not standardized, each button press on the looper will be able to send out no, one or more than one (!) PC and/or CC messages. I don't intend to add a a display to program the looper, so the configuration has to be done in the Arduino code (the message sequences will be functions, which you can customize to your preferences. It's not complicated and I will provide "building blocks", but with this approach, it would even be possible to send complex sequences, e.g. LFO-stuff via Midi :-))

I try to make the command sequences available as functions  in the configuration at the very beginning of the code, this should not be too complicated). I will use a complete Arduino Nano on the PCBs, so an USB-upload is easy.

How does this work (for this example, but you can figure out what you can do with this approach). Well, with a single button press, I could change to an HX preset (PC message), activate one of the three snapshots (CC:69 message) and activate a specific block in that preset/snapshot (e.g. a boost, with a non-reserved CC message).

And as a movie is easier to understand than many words, here it is in action:

First button press changes to Preset 34C, Snapshot 3 (right footswitch) and activates a boost (tiny block in the display, hard to see) Second button press activates Preset 35A, Snapshot 1 (left footswitch) and deactivates the boost