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.

Tuesday, November 6, 2018

Demedash Effects Incandenza Bypass

The Incandenza Bypass is a simple, low parts count, relay-based  true bypass circuit designed by Steve Demedash. It uses a normally open momentary SPST footswitch triggering a simple 555-based flip flop circuit, triggering a non-latching DPDT footswitch. The layout below reflects the pinout of the either the Takamisawa NA5W-K or Omron G6S-2 relays. These are 2 relays I had in my parts stash that worked with the circuit when I breadboarded it and are both rated at 5v. Other non-latching relays can be used, but double check the pinouts and compare datasheets. Schematic can be found here.



Note: Send goes to the effect input, Return goes to the effect output, In goes to the input jack, and Out goes to the output jack.

37 comments:

  1. Tried this with the only relay I had on hand to no avail. Hui ke 5v.. https://www.alibaba.com/product-detail/HK19F-DC5V-SHG-HK19F-DC12V-SHG_60792006629.html?spm=a2700.7724857.normalList.14.6ffc1693e8mPft
    Couldn't find a datasheet so took a punt... Bypasses fine. LED lights up when switched on but no audio. Tested with 2 working effects, same result. Guessing it's the relay. Cheers for this. Will get shopping for parts!

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    1. your relay doesn't have the same pinout as the one specified.

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  2. This comment has been removed by the author.

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  3. Hello, can someone explain to me what is this pedal exactly do? I understood that it was a bypass, but how to use this layout, must add it in with an other work ??

    Best regards,
    Franck

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    1. Use it instead of a DPDT in any pedal circuit

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    2. OK !! Thanks very much for answer !!! i understand now !!!

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  4. Hi! I've build one and can verify it.

    But! I really don't recommend it, since it produces huge voltage spikes when turned on or off. Voltage spikes reach 1-2vpp and are very audible sometimes. Tried with multiple ne555s

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    1. Ah, good to know. Thanks for verifying.

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    2. Hey, circuit designer here - can you be more specific about where the voltage spikes are happening? I've never had this issue and none of the builders I shared this circuit with before making it public reported anything like that either.

      I'd be happy to help you further debug. There might well be an overlooked issue that shows up only under certain conditions which is causing this. Curious to see what is happening here.

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    3. Hi, Steve!
      I've measured dem spikes on the VCC. To be fair, my psu was floating and nicely filtered and had somewhat 200uf cap on the input. I also should note that i've measured them with different relays (omron, takamisawa, nec).
      I guess, there should be some sort of overvoltage clamp, like a zener diode or whatever. I'm a bit messed up right now and can't remember all the details.

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    4. Steve,

      Curious if you would be willing to share a schematic, I would love to work this into my pedals.

      thanks,
      -david

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  5. With a 5v relay don't you need to add a voltage regulator to the circuit?

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    1. It works just fine with a 9v supply

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    2. 5VDC is the minimum voltage the relay needs to have applied in order to trigger. 30VDC is the actual maximum voltage rating of the relay IIRC.

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    3. >5VDC is the minimum voltage the relay needs to have applied in order to trigger. 30VDC is the actual maximum voltage rating of the relay IIRC.

      Wait, really? I thought the datasheet specified max of 200% voltage applied to the coil, that should be aprox 10 volts, not 30.
      Applying 30v volts will burn the crap out of 5v rated relay (na5w and omron gs6).
      Even operating at close to max vcc is quite bad for the relay and can affect it's life.
      I think, 5v reg is pretty mandatory for a proper long life.

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    4. I got some problem with this... I can't using battery, only adaptor.. Cause the circuit need bigger power...
      I will use a relay, where should I plug it in, before 555 or after pin 3 of IC 555 ??

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  6. Which relays do you use for your stripboard layout? Tried this one, yup, too noisy

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  7. Anyone try this with a kemet ec2 series relay? I'm new to working with relays, but looks like the pinout is the same as the takaminsawa?

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  8. Works great with G6S-2 relays!!! thanks!

    P.S. can you make this one with momentary mod??
    https://www.instagram.com/p/Bpse3QZnTVI/

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  9. Works well but gives a loud pop when engaged.

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  10. Did it and working but I have encountered an interesting problem.
    -I wanted to use the circuits Send/In parts to toggle the boost section of 7th heaven. When I connected the circuit, It somehow shorted the pedal. Than again I used a mechanical dpdt on that place.

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  11. Using other chip than ne555 (LM, LMC, ICM) will fix the noise problem, caused by ne555 shitty current spikes and coupling. Don't use ne555 ever.

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    Replies
    1. Thanks Plush, ordered some LM555CN’s. Let’s hope it works, the loud pops are driving me mad!

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  12. Have tried LM555CN instead of NE but I hear no difference regarding switching noise, it’s just the same loud pop. I think it has to do with the relay. Too bad! If someone knows the solution to fix this without extra circuitry please let us know.

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  13. Can I use the NA5W-K for this circuit ?

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  14. Hey, somebody know if I can use NA12W-K TAKAMISAWA relays that I have here at my workshop? it wold be interesting to try this!

    Thanks!

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    Replies
    1. The NA12W-K needs at least 9v across the coil to work, depending on what your power source is it might not work. If you ran it at 12v I think it would be fine.

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  15. I've made a bunch of these circuits and strangely the only 555 that will work is the LM555CN. I have a bunch of TL555s and NE555s and have not been able to get a single one to work, while the LM555s always work. Taking the relay out of the circuit lets the NE and TL 555s turn the LED on and off, but as soon as the relay is included it seems like it is causing the flip-flop to stop changing states. Any ideas on what may be happening? I'm using Takamisawa NA5W-K relays. Tired of overpaying Mouser for LM555s when I can get NE555s from Tayda by the bucketload.

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    Replies
    1. Very weird. They Tayda ones have always worked for me. And yeah the price differential between mouser and tayda on 555s has always confused me.

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  16. a noob question here.. how can i use this relay switching in a stereo mod output?

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  17. Is there an easy way to add a 2nd led? So that this could be in an A/B box.

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  18. I would like to request you please make a layout with 2 spst reply


    I cannot find 8 lugs relay
    Plz do make a layout with 2 spst


    :) thankyou

    I cannot find

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  19. can you make bypass layout from spst on off switch it use ic cd 4053

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