PedalPCB 5-Loop True Bypass Switcher

bhcarpenter said:
For a while I’ve been contemplating building a midi controlled relay bypass daughterboard to go inside of the stomp box itself.
Click to expand...

It should be relatively easy to add that to something like the Intelligent Relay Bypass module.

What type of connector would you use? 1/8"?

I need to take a crash course in MIDI... I'm not familiar with things like knowing which messages / channels you'd use for various functions.

I've used MIDI, but only in plug-and-play situations that didn't involve much (or any) configuration.
 
Robert said:
It should be relatively easy to add that to something like the Intelligent Relay Bypass module.

What type of connector would you use? 1/8"?

I need to take a crash course in MIDI... I'm not familiar with things like knowing which messages / channels you'd use for various functions.

I've used MIDI, but only in plug-and-play situations that didn't involve much (or any) configuration.
Click to expand...
It’s amazing that it’s been around for over 40 years now, and has been relatively unchanged (something almost unheard of in the datacom world). Also surprised that for how old it is, how much of a mystery it is to a lot of us.

That said, from what I’ve been seeing in my limited research, it’s quite simple to configure using an arduino compared to what they likely used in 1983!

Thinking of midi, and how the I/o is specified to use optical isolation to avoid ground loops, I would also want to question if the use of isolated jacks are going to be recommended as the potential for ground loops goes up with a switching box like this.
 
Robert said:
What type of connector would you use? 1/8"?
Click to expand...
Yeah, 1/8” trs like the MIDI enabled Boss pedals.

MIDI is a serial protocol that’s supposedly pretty easy to implement if the microcontroller has a UART. Here’s what I had in mind, though it could probably be simplified:

One microcontroller for the MIDI interface, and then a separate microcontroller for each relay needed by the pedal (so two for a dual footswitch pedal, etc).

MIDI Module: ATTINY212
  • 2 pins UART
    • MIDI In
    • Program # to expansion modules
  • 1 pin Digital I/O
    • (opt) Save button in
  • 1 pin External Clock
  • Persistent Memory [4 bits]
    • [4 bits] Channel #
Expansion Module: ATTINY412
  • 1 UART In
    • Program # from MIDI Module
      • Resend current program to save current setting to persistent memory
  • 4 Digital I/O
    • Footswitch in
    • Relay On Control out
    • Relay Off Control out
    • Relay Status LED out
  • Persistent Memory [128 bits]
    • [128 bits] Program # -> On/Off
MIDI Implementation:
- Program Change : recall setting
- CC 119 (any value) : save current settings to preset specified by the CC value
 
Giorfida said:
I would also want to question if the use of isolated jacks are going to be recommended as the potential for ground loops goes up with a switching box like this.
Click to expand...
Good question! I believe only the MIDI in jack would need to be isolated, right? Unsure though. Maybe the input would be grounded to the box, and the rest of the jacks are isolated?
 
bhcarpenter said:
Good question! I believe only the MIDI in jack would need to be isolated, right? Unsure though. Maybe the input would be grounded to the box, and the rest of the jacks are isolated?
Click to expand...
I’d personally want to isolate all the jacks. Never know what kind of power supply someone is using, or if they are throwing the preamp of their actual amp in one of the loops. Isolated jacks could keep the grounds to each send/receive pair bussed, but isolated from other pairs. Not a true isolation but likely enough for most situations
 
Of course I’m not thinking straight. Isolating the loop jacks from
The master I/o jacks would likely make the connection not work.
Another option- a dip switch bank that would allow any jack have their ground lifted. That would make more sense.

May be overthinking it, but I’ve dealt with ground loops in the past that were a nightmare to troubleshoot (catch me on a side conversation about the old metal DOD pedalboards from the 80s)
 
If all the pedals and the switcher are powered via isolated supplies the risk for ground loops should be minimal.

If we want two outputs, having at least one of them isolated (via transformer) would avoid ground loops between the two amps.

Am I missing anything?
 
3 scenarios you could be missing
- using one of the loops to put your amps preamp in the loop (ie 4 cable method), in which case it would be a crapshoot as to what you would want to isolate. So ground lift switches for all jacks would be cool and I’d think easy to implement
- metal pedalboard + metal cases pedals. Yes the Velcro could provide isolation, but some folks zip tie or use other attachment, which could introduce another common ground path.
- use of snake cables or other multi conductor cables- some of which share grounds.

And of course the “budget” isolated supply that isn’t really isolated
 
Where should the dipswitches be located?

There isn't room on the back side with the jacks, so we have three choices....

Face of the enclosure, front side (facing the player), or internal.
 
Robert said:
Where should the dipswitches be located?

There isn't room on the back side with the jacks, so we have three choices....

Face of the enclosure, front side (facing the player), or internal.
Click to expand...

What are the dipswitches for again?
 
Big Monk said:
What are the dipswitches for again?
Click to expand...

Playing around with a design for a version of the switcher where the banks are programmed by dipswitches, similar to the Octa-Switch.

PedalPCB 5-Loop True Bypass Switcher

Creating this thread as a place to consolidate all the ramblings about the upcoming true bypass loop pedals
forum.pedalpcb.com forum.pedalpcb.com

It may never happen because it's just as easy to program with the footswitches, but we'll see...
 
Yeah, inside. I won’t see needing to switch that on the fly. You’re right, it is easier to do it with the foot switches, which wouldn’t get programmed in the fly either.
 
Robert said:
Nah, and putting them on the face like the Carl Martin seems like a horrible idea.

I don't think dipswitches are designed for the amount of dirt and crud that is going to end up in there.
Click to expand...

I think the overall appeal of the Carl Martin is brute force programmability.

Obviously a microcontroller based unit controlled by footswitches is far superior. The Joyo switcher in particular have a crazy amount of functionality for such a simple interface.

The only thing I'd like to see improved upon was switchable buffers, a stomp mode and maybe order switching of specific loops. There are times when I want to switch the order of my Fuzz and Wah on the fly.
 
Big Monk said:
I think the overall appeal of the Carl Martin is brute force programmability.

Obviously a microcontroller based unit controlled by footswitches is far superior. The Joyo switcher in particular have a crazy amount of functionality for such a simple interface.

The only thing I'd like to see improved upon was switchable buffers, a stomp mode and maybe order switching of specific loops. There are times when I want to switch the order of my Fuzz and Wah on the fly.
Click to expand...
I have a switcher now that has 2 inputs. One buffered and one non. It can definitely be handy.
 
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