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.

Monday, March 6, 2017

Death by Audio Echo Dream 2

Gotten a lot of requests for this one. I've put it off because the schematic that's out there isn't exactly straight forward, not to mention it's 7 pots, 2 switches, 3 ICs... You get the idea. Anyway, I wanted to keep this 1590BB friendly, so all the pots are board mounted... except one (Blend). Six out of seven isn't bad, I reckon. haha


71 comments:

  1. i was waiting for it

    This one is very strange actually, XR definitely lacks voltage to operate correctly, when powered by 9v it does not generate any wave. Better power it with 18volts, but it may overheat 5v regulator...

    Anyway, magnificent job, as usual.

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    1. I'm looking at the 78L05 datasheet and it looks like the max input voltage is 35V. I'm by no means an expert on reading datasheets so I may be wrong about this...

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    2. Yep, Ian, you are right.
      My bad.

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  2. Sweet! This is one on my bucket list, I was thinking about doing the Vero version, but wiring 7 pots offboard... Ugh. Thanks man!

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  3. TL072 would work in place of MC33172P?

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  4. Do you do the drilling templates in Eagle?

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  5. Just to let everyone know, there had been issues at the tagboard forum with powering this effect at 9v. the xr2206p chip's says on it's datasheet that it's operating voltage is from 10v to 26v, so a lot of people had reported that the modulation section was not working when using 9v batteries or power supplies. They recommended just making a simple voltage doubler and powering it at 18v!

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    1. Those charge pumps give me endless grief :\ Though the klon clone I made from a layout here works fine.

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  6. oops i didn't read that first comment :p

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  8. DBA released the Micro Dream recently! It seems like a (twisted) stepson of the Echo Dream. I'll be waiting that layout for sure! Haha

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  9. hi excellent layout but remplacement of XR2206P?? please thanks so much

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    1. Sorry, Esteban; there isn't a replacement.

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  10. Fuzz knob isn't doing anything on my build. Everything else is peachy. Too tired now to troubleshoot, if anyone has any ideas, let me know.

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  11. 4 wires must be connected to sw1
    but layout has pads only for 3

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    1. One of the pads goes to 2 lugs of the switch. You don't really need an extra pad. Just run a wire between lugs 3 and 6 and a wire from there to the board.

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    2. No, there should be at lest 4th wire.

      There is no point in using 2 contact groups in DPDT with 3 wires and 1 jumper like this: http://i.imgur.com/m92ka6l.png - it makes no sence, jumper between 3 and 6 does literally nothing ;-)
      Even if you place it between 3 and 4 or 3 and 5, it will still do nothing since pins 2 and 5 are not connected to each other.

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    3. I'm with you now. Yeah, there was a 10k resistor from the voltage to switch pins 4 & 5. Updated the layout and it should be good now. Thanks for catching that.

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    4. So you switched the 4.7k resistor to 10k and have the former LED+ going to switch 1, 4 and 5 correct? Was there any other changes?

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    5. Other than moving the LED resistor over to the left, no.

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  12. Hi all!

    I've just finished the DBA Echo Dream using this layout and I have some troubles:
    1. the Fuzz pot do nothing (no fuzz)
    2. the Depth pot have a little effect (and it never goes to 0 for unmodulated signal).
    3. the overall volume is under unity
    4. the switch 2 acts strange in a position

    I tried MC13382 and other op-amps instead MC13372, with no luck.

    Anyone built it succesfully?

    Thank you very much!

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    1. Same exact problems that you had. I gave up on trying to figure it out.

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    2. I will try to recheck the PCB as soon as I will have some time...anyway, the schematic from FSB is a little unclear to me...and I have limited electronic knowledges.

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    3. What voltage are you running at? I am using a 555 charge pump and wondering if the 18 volts might have fried something in the chain? Also, what voltage are your electrolytic caps rated at?

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    4. I'm running it at 18V (a Dunlop power supply), because I used electrolytic caps rated at minimum 25V. As I read on other forum, it must be OK

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  13. I found first mistake in the schematic from FSB: the 220nF is only 220pF!!! The value of 220nF for a cap in a feedback loop of an op-amp is ridiculous and kills all signal. In the hand drawn version the cap is 221, but in the redrawed version it becomes 224.

    Now, the Fuzz pot acts OK and the overall volume it's OK when you set the Fuzz pot at 8-9 o'clock (which is normal, because the Fuzz pot is esentially a gain pot).

    Anyway, the Depth pot has almost no effect and the switch for the sine waveform sounds horrible (for the rectangle waveform sounds nice).

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  14. I found a mistake in the layout: the SW1-2 must go to pin 2 of the Depth pot (instead of pin 3, as is). Now the Depth pot works OK, but I am not sure if SW1 works OK or not (it sounds a little strange for my taste on the sinewave side).

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  15. I believe that both 220nf and 47nf are wrong and in their place must be 220pf and 470pf....although in tagboard and effects the 470pf is connected with the in pad!

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  16. Hello everyone, today I finished mine with the suggested changes of the two capacitors, sounds great.
    Just have a problem, you hear the clock, I do not know if it's echo or modulation, any suggestions?
    It's a fantastic pedal, thank you!

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  17. You can mark this as verified! It fired up right away with the change of caps mentioned above but needed some things to be changed too for this guy to reach his full potential.So i will mention all those things above:
    1. Change of caps 220nf (near the fuzz pot) to 220pf AND 47nf (above the input) to 470pf
    2. Sw1-2 to Depth lug 2 so you can activate the depth pot otherwise it will be all the time at full.
    3. XR2206P operates fully between 10 and 24 Volts , at least according to it's data sheet, so i put a 555 Charge pump just to see how this affects the circuit and...boom!! At 9Volts i could get a saw waveform (kinda odd and a little crazy if you ask me) and a squareish from the modulation section. At 18Volts you get a pure singing sine waveform and a strong sqare wave.
    I wanted for so long to build this pedal , so thank you so much for helping me achieve that man!!!
    Jiomy

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  18. Can anyone post a demo video? I'm interested to see how they sound!

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  19. I have a question: the capacitance of 32nf is very difficult to find. Can you use 33nf instead?

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  20. Still unverified? Do i have to post a video to verify it?

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  21. Hi,when I use a depth, there will bi obvious out-of-tune,rather than normal waveforms, why?

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    1. Sw1-2 to Depth lug 2 so you can activate the depth pot otherwise it will be all the time at full.

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  22. Just built mine up everything working except for xr2206p... Does anyone know where to get 2206 voltage readings table from?

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  23. Found the problem re XR2206P.. got a couple of fake chips unfortunately so ebay'd the function generators and works well. Sinewave seems like a double step square wave (up normal down normal up ...) while square seems posi square (up normal up normal) so will play with the sinewave resistor (10k might need tweaking?)

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  24. it possible to make the micro dream delay from this circuit as well? I assume just include the controls for feedback delay and volume right? How could we do that?

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  25. Hi ! I've just finish mine ! Very good job ! The normal echo is working very well but the modulation doesn't work.
    The speed knob don't have any effect.
    Have you got an idea ? Thks !

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    1. When i turn the depths pot, it modify the speed of the echo, the speed doesn't do anything and when i turn the switch in square mode, i'm losting the first signal (dry?), i've only echos.

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    2. I'm runing it in 9v with a 555 charge pump, i've 17,5v when the circuit is not connected, and i've a voltage drop to 14,5v when i connect it.

      Here are my voltage :
      33172 :
      5,1 10,2
      5,1 . 5,1
      4,8 . 5,1
      0 4,8

      Pt2399
      5 . 2,5
      2,5 . 2 5
      0. 2 5
      0 . 2,5
      2,2 . 2,5
      2,5 . 2,5
      0,7 2,5
      0,7 2 5

      2206
      0 . 1
      5,1 1
      5 7,7
      10,2 8
      10,2 . 0
      9,9 . 2,4
      3,4 . 3 5
      4,3 1,5

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    3. The same with me... Modulation is not working.

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  27. Everything works (echo, fuzz) except modulation. It could be issue with fake 2206 chip? When I first time plug power on (18v) 100ohm resistor started to be very hot. I removed xr2206cp and it was ok. Then I inserted 2206 and it happen again. I inserted another 2206 (have two pieces) and it happen again. Just had read about issues with fake chips on web.

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  28. Bought another 2206 and everything started! Now modulation works! Verified, thanks a lot brother!

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    1. Just to mention it - verified with the changes mentioned above by Jiomy.

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  29. Great job! Thanks, everything is working!

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  30. kudos on managing to interpret the schematic that's out there. I was about to put a board together but wow. that's some indecipherable stuff.

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    1. trying to compare your layout to the schem. Switch 1-2 seems to connect to depth-wiper on the schem, and you have it on pin 3. have i missed a better schematic somewhere?

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  31. Does anyone have the schematic lying around. Would like to check it out and compare to try and breadboard this out first.

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  32. all seems to work well except for the time knob, if the time knob is set to 0 I hear a strange throbbing pulse under my normal signal..

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  33. verified! but that was a very tricky build.
    first of all, like the older comments said; i changed the 47nf and 220nf, connected the sw1-2 to depth 2 and they were all correct. and i finished the build with a (probably fake) cheap(2$) xr2206cp. as expected, the modulation part didn't work. but a few days ago, after a detailed research i found an original xr2206p in my country and it was about 6$. just tried the circuit with it, and now everything works like a charm. so yes, this layout is very picky on the modulation ic. try to find an original one.

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  34. Verified! Made one used the advices about caps and sw1, powered by charge pump and it works! Designing an enclosure now, with a button for infinite feedback, great pedal! Thanks!

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  35. I think the 1uF at the Master pin 3 should be the other way round.

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