This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Wednesday, August 3, 2016

Tails Bypass Looper

Someone from the Offset forum asked me about building a looper pedal that when used with a delay pedal would have "tails." For those who don't know, "tails" is when a delay is switched off, but the remaining repeats come through the bypass signal. This is a popular mod to the Deep Blue Delay and other delays that feature input and output buffers. What if you don't want to mod an existing delay? Then build one of these. I laid this out 2 ways, one with relay switching and one using a simpler latching DPDT footswitch. With the latter, wire the Send pad to lug 2 of the footswitch, with lug 1 going to the Send jack. The other side of the footswitch can be used for LED on/off indication. The Return jack should be wired directly to the Output jack. The non-relay board could probably be squeezed into a 1590a if using low profile jacks.

47 comments:

  1. is this along the same lines as an Octa Switch? and would a project like that be possible?

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    1. Not really, though you could use this is a big looper pedal like the Octa Switch for delays. The basics of a looper pedal like the Octa is essentially this:

      http://1.bp.blogspot.com/-SzM32SDZGdM/UX_DmZFl5aI/AAAAAAAAFhg/Bp3b9omf8Ds/s1600/TB+Looper+5+with+buffer+and+tuner.png

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  2. This is a really cool idea - looking forward to giving it a try!

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  3. hi, omron G6SU is rated 5 or 12V. I assume it's the 12rated here, right?

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    1. Go with the 5v actually. I got them off ebay for fairly cheap. The relay portion of this is the same circuit as the Relay Bypass layout.

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    2. thx for answering, I thought that a 5V relay would be fried by the 9v supply.

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    3. Yeah I thought the same and originally I used a 5v regulator on the Relay Bypass, but it didn't work. Pulled the reg and gave the regulator straight voltage and bam. Worked just fine.

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    4. yeah that was exactly what I was doing! but the reg keeps heating and such with a relay. Thanks for the help!

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  4. Can anyone please explain just step by step the wiring of this thing?

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  5. Hi!
    I wanna give it a try, but I have a question that doesn´t let me start. Where/How do you connect the guitar and the delay pedal? What do I have to connect at the IN, OUT and SEND? Thanks in advance!

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  6. I am a little confused by the wiring, I have everything to try it but I can't figure how to do it :(

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  7. Awesome idea, I'd jump into, but I also not really getting how the wiring goes.
    I seem to miss the return line of fron the delay.

    Could you, guys, explain it somehow?

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  8. As far as i understand, this is a pedal with 4 jacks: In, Out, Send, and Return.

    Wire the In jack directly to the In pad on the board. Wire Return and Out jacks to the Out pad. Wire Send jack to pin 1 of a DPDT footswitch, then wire pin 2 to Send pad on the board. If you want, wire pin 4 to LED+ (with a 4k7 resistor) and then to +9v, pin 5 to ground.

    Now you have a looper which you can plug into any already existing delay and switch off the input to that pedal without killing the output.

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    1. Guess I should also explain:

      Your guitar is plugged into In jack, Out jack goes to your amp, Send jack goes to input of delay, return jack goes to output of delay.

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    2. isn't it trail's? i always thought it said "with trail's" not tail's lol shows what i know

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    3. hi Ian,

      thanks for your explanation.

      Based on the dmaller baord I've built my tails looper, but it's not working properly.
      If I plug everything the dry sinal goes through both on and off state, and no effect from the delay.
      If I disconnect the board's output, then the wet signal can be heard when on without any attenuation. But if I connect back the out from board, again just the dry signal can be heard, nothing else.

      Do you have any idea what went wrong?

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    4. I'm Attila, just somehow my login screwed up. :)

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  9. the second and small layout 100% verified ,

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    1. This comment has been removed by the author.

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    2. Hi Dan! Can you help me with the wiring? How did you wire it? Can you send me a pic?
      https://www.facebook.com/emanuel.chaves
      Thanks in advance!

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  10. https://www.youtube.com/watch?v=B4oswHABYhI

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  11. is the 560R value at all critical? looks to me like i might be able to sub anything in that neighborhood as long as they are the same for both send and out.

    I just placed orders with both digikey and mouser today and totally forgot to order that value. I have them in carbon film but i am one of those metal film 1% snobs.

    470R i have a bunch of, 680 too.

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  12. If i want to put it inside the pedal what would be the wiring? I've been smashing my head against the wall the last hour or smth , can someone help me understand this?

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    1. I also want to make the tails be switchable , don't care if its buffered bypass just being curious to know how to make it happen.

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    2. * Input (from guitar) to the tails input.
      * SEND to dpdt lug 2.
      * Dpdt lug 1 to the effect input
      * Effect Out to pedal out.
      * Tails out the pedal out.

      Both outs join at the pedal out.

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    3. Yeah but what if i want to make tails switchable?

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  13. Hi everyone.

    I seem to be having some weird issues. I've built the small layout.
    So far it works.. sort of. However, when it's bypassed and the pedal in the loop is on, the signal loses a lot of volume, and only picks back up when the pedal in the loop is switched off. That is, if it's a true bypass pedal. With a buffered pedal, the issue is more permanent.
    I've checked and double checked wiring and I seem to have done everything according to instructions. Does anyone have any idea what I could hypothetically have done wrong? I've come across some folks in the comments on another board talking about phase inversion. Could that be the issue?

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    1. im having the same issue... still looking for any idea..

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    2. Dame problema here. Simeone solved it?

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    3. And same problem here. The circuit works fine except in bypass mode, in my case there is no signal at all. Unplugging the power of the delay or disconnecting the return proves that all the wiring etc is okay. If it is phase inversion, is there a way to fix that?

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    4. El bucle funciona, aunque también tengo problemas de caida de volumen. Creo que la solución más rápido es agregar impulso (LPB-1?). No consigo encontrar este esquema en Google...

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  14. This might help those whose pedals suffer from 180 degrees inverted phase problems: https://www.parasitstudio.se/stripboard-layouts/simple-buffer-and-phase-inverter

    If the phase is slightly off I do not see any possibilities to fix it though...

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  15. If I would add a pot into the returning "wet-only delay signal" would that work as dry/wet-mix? Or should I wire the DPDT in way that when effect is engaged the "out pad" is cut out from the out jack and use pedals own wet/dry mix knob?

    Ps. Noticing little bit of overall volume drop (-6Db or so) on this build, yet nothing that cranking up the gain from amp could not fix.

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  16. Hi! Is there any schematic available? Thanks!

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    2. Hola! Esquema de esto? La placa chica sufre problema de caída de volumen...

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  17. thanks for this wonderful site. I've built the BE OD and it work the first time. I would like to know. If you skip the bypass looper and simply put an extra connection in your true bypass wiring, like putting the fx out to the output switch. wouldn't it be doing the same function. cause once you switch to off, it would stop feeding signal to the PCB but the FX out will still be connected the out to the output SW. And you'll have true bypass. I just wonder...

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    1. Sorry I mean to say this
      thanks for this wonderful site. I've built the BE OD and it work the first time. I would like to know. If you skip the bypass looper and simply put an extra connection in your true bypass wiring, like putting the extra cable from the fx out TO THE OUTPUT JACK. wouldn't it be doing the same function. cause once you switch to off, it would stop feeding signal to the PCB but the FX out will still be connected the out to the output SW. And you'll have true bypass. I just wonder...

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  18. does anyone know where i can find the transfer image of this?

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  19. i looked in the misc folder, but no luck...

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  20. Armé el circuito chico. Lo conecté a mi EQD disaster transport, y cuando activó el bucle pierdo volumen notablemente. Alguna idea para solucionar esto?

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  21. Great idea! Is it possible to have the schematic? thanks

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  22. Bagaimana cara kerjanya??apakah sama dengan line selector boss??

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