Eoo3: Programmable Looper/Switcher/Midi Controller

[Marshall Arts]

Operational Manual finalized as well. Everything you need (code, documentation, drill templates, images, ...) is here

https://drive.google.com/open?id=1lKUyPn5B468xeWaGFZhAdqgFoZD4oujD

Enjoy!

[cooder]

Absolutely monumental and brilliant work! Excellent show of the genius of DIY and how you managed to adapt it to your requirements.
Amazeballs!

[Wolfonso]

Updated Post as I ran out of enclosures AND German Post changed their conditions:


PCBs:
The set of 6 PCB's for the looper will include:
- 15 Jack PCBs (on a v-slotted board, you only need 8 of them)
- 8 Loop Button PCBs (on a v-slotted board, you need all 8 of them)
- 10 Preset Button PCBs (on a v-slotted board, you only need 7 of them)
- 1 Control Board (for the Arduino Nano, the Shift registers, the Power connection, Midi in and out and the Button connections)
- 1 Spillover Board (for Amp Switching and Spillover Loops seven and eight)
- 1 Relay Board (for the Input Buffer, Loops 1-6, send/return)
- 12 Distance rings for the PCBs
25,- EUR

Shipping and packaging (EU): 5€
Shipping and packaging (Non-EU): 9€

If you want to get one set, here is the link to the preorder-thread: http://www.madbeanpedals.com/forum/index.php?topic=29576.msg286399#msg286399

Hi, is this still available?

[Marshall Arts]

Yes. I send you a PM.

[vagos21]

Hello everyone, it's my first time here and boy oh boy what a wonderful forum this is! I might need to start a new thread for my own programmable looper build which is coming very soon... But I have a couple of questions that the experienced looper builders might be able to help with 

I have separated stomp unit and relay unit (to add new stuff whenever needed and be more versatile away from the pedalboard
So the stomp unit has a touch screen to be programmed easily. The relay unit features 10 loops, midi out, 4 amp switches, switchable buffers for input and output (adjustable gain too) and I am currently working on the trails mixer for loops 9 & 10. But FOR THE LOVE OF GOD, how do I get rid of the true bypass relay pops? I've been reading about true bypass for days, and it seems to come down to either accepting the pop, or muting the output for 10-20ms until the switching is complete.... So what are your thoughts? Which circuit do you use for that job, and whych parts do you mute, output only?

Thanks for your patience...
Vangelis

[Marshall Arts]

Hello everyone, it's my first time here and boy oh boy what a wonderful forum this is! I might need to start a new thread for my own programmable looper build which is coming very soon... But I have a couple of questions that the experienced looper builders might be able to help with 

I have separated stomp unit and relay unit (to add new stuff whenever needed and be more versatile away from the pedalboard
So the stomp unit has a touch screen to be programmed easily. The relay unit features 10 loops, midi out, 4 amp switches, switchable buffers for input and output (adjustable gain too) and I am currently working on the trails mixer for loops 9 & 10. But FOR THE LOVE OF GOD, how do I get rid of the true bypass relay pops? I've been reading about true bypass for days, and it seems to come down to either accepting the pop, or muting the output for 10-20ms until the switching is complete.... So what are your thoughts? Which circuit do you use for that job, and whych parts do you mute, output only?

Thanks for your patience...
Vangelis

See schematics for the E003. I use a solid state relay to mute just the output for 10 ms. However, another problem is a couple of leds changing, which might feed back into the power or Gnd rail. This is nasty, esp. With delays in the spillover loops. Read r. G keen for some approaches on how to fade in leds slowly to prevent popping.

[vagos21]

Thank you for the fast reply doc! I already implemented the 10ms output grounding, but it was still popping right after the silence. So I decided to look elsewhere, and what would you know, it's the op amp of the blend circuit, caused by something they call input offset voltage? Reading and learning forever! It creates 15mV on output, which results in a wild pop when the blend is activated/deactivated. So now I'll have to either choose a more expensive op amp or find a good way to adjust that offset  did you run into similar problems?

[Marshall Arts]

I only have blend circuits in the spillover loops, and it's actually not too much popping. Can you point us to the sources you found? And maybe a schematic of that part of the circuit? And yes, maybe a separate thread in this forum to discuss your circuit and how to fix it...

[vagos21]

Marshall Arts,

Forgive me for getting a bit technical here, in your spillover schematic, i see the return signal gets into the mixer, and the IN signal gets buffered and then into the mixer. shouldn't both stages be buffered before blending? Doesn't it affect the tone? I'm a newbie, i'm just asking to learn 

And a second question, the return is always sent to the mixer, even if the spillover is not used. so it's split into the mixer and the output. Doesn't this create impedance mismatch affecting the tone again?

In my version of the spillover, i use 3 relays to make sure the signal doesn't get split there. Is it useless to do so?

I hope i explained these well, thank you for your patience!
I will draw schematics by hand and upload them when i get some more time 

[Marshall Arts]

Different approaches have been discussed in this thread

https://r.tapatalk.com/shareLink/topic?url=http%3A%2F%2Fwww%2Emadbeanpedals%2Ecom%2Fforum%2Findex%2Ephp%3Ftopic%3D28875%2E0&share_tid=28875&share_fid=53198&share_type=t&link_source=app

[Marshall Arts]

P. S. The E003 uses jumper switches to change loop 7 and 8 to true bypass loops. The return signal is buffered by the effects in the loop. I Breadboarded a lot, and this solution was the best I found.

[vagos21]

Wow thank you endlessly for all the info and links! I will give it a shot today or tomorrow on my ever changing breadboard 

And one last question, do you think it's worth it to include phase reversal for blending? I mean, did you come across any cases where it was needed? as far as i can see, it's not included in the looper schematics?

Thank you for everything, will post results as soon as it's all done that color LCD looks really nice with every bit of info on it, also the touch screen makes it a breeze to program

[Marshall Arts]

I decided to skip phase reversal... Never needed it...

[vagos21]

Marshall Arts, I visited, examined and tested everything you suggested in that link, but things didn't work out well... On the other hand, your looper schematic works perfectly in terms of tone and volume and function, it's really amazing! BUT I still get that huge pop when spillover is turned on or off via relay, it's not that innocent bypass pop, it's something else... Measuring voltage at the output Jack I get 0V when bypassed, 0V when fx is on, but 1.1V (!!) When spillover is activated (constantly). It's that big voltage difference that makes the huge pop... Any ideas on that?

[Marshall Arts]

Marshall Arts, I visited, examined and tested everything you suggested in that link, but things didn't work out well... On the other hand, your looper schematic works perfectly in terms of tone and volume and function, it's really amazing! BUT I still get that huge pop when spillover is turned on or off via relay, it's not that innocent bypass pop, it's something else... Measuring voltage at the output Jack I get 0V when bypassed, 0V when fx is on, but 1.1V (!!) When spillover is activated (constantly). It's that big voltage difference that makes the huge pop... Any ideas on that?

Is that 1.1 V DC? Hard to imagine, as the only connection to the output is a cap (e. G c27 for loop 7) and a resistor to Gnd (r52) for bypass in spillover mode. For fx on in spillover mode it's just the return signal and a resistor to Gnd (r40) and another cap (c30). Did you try other caps as well? There should not be any DC in that part of the circuit.

I will check with my Looper, but it will take some weeks... I don't use the spillover loop and don't want to rip my board apart right now.

Maybe I find time for breadboarding, who knows.

Please post the schematic you are using, and where you measure what. Or at least pictures of your breadboard.