# My first design -- multi effects loop switcher



## Steve973 (Jun 16, 2022)

Hi, all.  I have mentioned this to a couple of people (privately) so far, but there hasn't been much interest.  I'll describe what I'm doing here in case anybody is interested in hearing about it, or maybe even messing around with it.  I am designing a multi effects loop switcher that can be set up in either 4 or 8 "rail" configurations because the boards are designed to be modular.  You can use one set of boards for 4 rails, or 2 sets of boards for 8 rails.  That's the quick and dirty version.  Ok, maybe not so dirty?  I don't know if you're all over 18 or not!!!  If this is completely uninteresting to you, then now is the time to bail out of here and move on to cooler and more interesting threads, because the deep dive follows.

Most of you are aware of Jack Orman's circuits, right?  I am pretty new to pedal building, and in my searches, I ran into his site and found two circuits that really interested me:  a JFET splitter, reported to be quite transparent as far as active splitters go, and an op-amp mixer circuit that also has a ton of positive commentary on it, too.  I have been interested in an effects loop box so that I can isolate some of my bass effects pedals, and switch pedals or short chains of pedals on and off as needed, but I didn't see any with all of the features that I wanted.  I grabbed these two circuits and taught myself how to use KiCad.  I designed boards for both circuits that can be used alone, or they can be tied to a second board of its type.  I.e., you can use one splitter and one mixer, or you can connect two splitter boards (and two mixer boards) together by using a wire between the Molex headers on the boards.

So far, this is just like any effects loop switcher box.  What is missing from pretty much all of the ones that I found was an XLR board-level output.  This was really easy to add, because Jensen has some schematics online.  I designed a board with a circuit that incorporates a Jenson step-down transformer for XLR out that will be parallel to the original signal output (1/4 phono).

The board(s) can be run on a wide variety of voltages for more headroom, if desired.  Since I am not an EE, I am not really sure what would be close to "ideal" for the 4-rail configuration, and what would be ideal for the 8-rail configuration.  Either way, there is a trim pot for the power that goes to all of the switch LEDs to adjust the brightness for whatever voltage you use, and whatever brightness is good for you.

I would like to add USB output, just for fun.  I bought a Teensy 4.0 with their audio shield to play around with, once I get boards fabricated and do my first build of this.  I am probably going to use OSH Park (recommendation from a friend), and I'll get boards made sometime soon.  This is all just for fun and learning for me, and I would be happy to share what I have, so far, with anyone who might want to have a look and play around.  And even inform me of mistakes and bad assumptions that I made.  Just let me know, and I'll give you the KiCad 6 projects that I have for the 3 boards.  If you actually made it this far, thank you for reading.


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## Steve973 (Jun 16, 2022)

Just for clarification...  When I say that I "designed" the boards, I specifically mean that I transposed these schematics that I found into KiCad 6, and created a PCB layout.  I didn't create any of this myself, other than some very, very minor modifications.


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## Feral Feline (Sep 2, 2022)

Bump for an update on this interesting project.


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## Steve973 (Sep 9, 2022)

I had a friend looking at my boards.  He is an EE and designs boards, and I thought that it would be wise to let him check my very novice work.  He hasn't gotten back to me yet, so I haven't gotten the boards fabricated yet.  But I haven't forgotten!


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## iamjackslackof (Dec 16, 2022)

I'm working on my own multi-loop switcher, and this sounds up my alley. Do you have any schematics or anything?


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## Steve973 (Dec 17, 2022)

iamjackslackof said:


> I'm working on my own multi-loop switcher, and this sounds up my alley. Do you have any schematics or anything?


Yes, I have the entire project done in KiCad6.  It has schematics and board layouts.


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## giovanni (Dec 17, 2022)

This sounds interesting. I assume this is gonna be fixed order?


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## iamjackslackof (Dec 17, 2022)

Steve973 said:


> Yes, I have the entire project done in KiCad6.  It has schematics and board layouts.


Are you planning on releasing the schematic, or building pedals to sell?


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## Steve973 (Dec 17, 2022)

iamjackslackof said:


> Are you planning on releasing the schematic, or building pedals to sell?


I made this design by taking circuits created by Jack Orman, so I don't think I would have the legal right to do that.  I have no problem sharing what I have with anyone.


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## iamjackslackof (Dec 17, 2022)

I'd love to see the schematic then if you're keen.


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## GratefulEight (Dec 17, 2022)

All of that!  I have some ideas for a switching system bouncing around in my head but if you've already got a project put together I would love to get a look at it too.


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## Steve973 (Dec 18, 2022)

Ok, guys, I'd be glad to share what I have.  I designed it to be modular, so these are in 3 separate projects, and you connect the boards by the molex connectors on them.  You'll see what I mean, but if you have any questions, don't hesitate to ask.  Also, if you're more experienced than I am with circuits and board layouts, I'll welcome constructive criticism because I always like to learn better ways of doing things.

The only question is how to get the kicad stuff to whomever is interested.


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## Steve973 (Dec 18, 2022)

A note on the modular design...  The main board has 4 channels on it.  So, you can make this either a 4 channel switcher, or an 8 channel switcher, depending if you use 1 or 2 main boards.  I also have not designed an enclosure for this.  If anyone designs an enclosure, I hope that you will also share what you've done.


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## GratefulEight (Dec 18, 2022)

PM sent.


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## Steve973 (Dec 20, 2022)

iamjackslackof said:


> I'd love to see the schematic then if you're keen.


Let me know how to get it to you.


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## Feral Feline (Monday at 11:21 AM)

Take a screenshot of your schematic in Kicad, then post the screenshot.

I don't think there's a problem with that, as you've already cited your source (AMZ) and tweaked it, thus making it your own.


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