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, July 26, 2017

DeadAstronaut Chasm Reverb

Been a while since I did a reverb layout and this DeadAstronaut design does not disappoint. It's not a true-bypass effect, but uses some JFET switching so that tails are present when you turn the effect off. Coda Effects actually has a really good write up on the design. Ended up doing this one in Eagle and was able to squeeze it into a 125B. If you want a fabricated board, you can order some off OshPark.

Here's the build doc with the BOM, schematic, and drill template.


  1. What do you need to confirm? ))) I made a circuit, everything works, I just changed the values of C8 and C9 put 22nF both, (trying to move the oscillation to the high-frequency region area). Due to this, we had to reduce the values of R11 and R12 to 33k and 68k.

    1. Did you bread board this or did you build it on this board?

    2. I apologize for my English))) I'm building it on this board. Slightly changing the nominal values.

    3. You're English is fine. When someone verifies something so fast I'm always a little blown away. haha Thanks for verifying!

  2. I have the ability to speed up the build process. Since, I am engaged in repair and modification of guitar effects and amplifiers. I have the equipment, details and experience. )). The reason for rapid assembly and debugging. I want to say that you are very logical and repeatable PCB`s. You make a very interesting and useful site, with a wonderful set of schemes and recipes.

  3. One more, working ok !!
    It took me a little longer because I had to wait for the BTDR-2H-L, which is difficult to find.
    I had some problems on the way, at first there was no sound, then I noticed that the accutronic mounted on top of the components, as it seemed that it was in the drawing, was with the pins all inverted, or put it on the side of the solder, which It forced him to weld it, and I did not want to know if the circuit was going to work, so I ended up putting it in the socket on the side of the components but turned upwards. I started to have reverb but the general sound was very low and with noise, I tried to change the ICs for a JRC4558 and improved a lot more gain and less noise, I still tested with some OPA2134, eliminated almost all the background noise but the overall volume Went down a bit, and I ended up going back to the JCR, which gives it a more analogical touch. Even though the gain seemed a little too low, I had already changed the 2n5457 from two different lots without major changes, it was the turn to test ones in SMD MMBF5457 and some mini pcb's adapters that I got in aliexpress, and the problem was sorted out. The values ​​of the others I was using had values ​​between I = 0.80 / 0.90mA and VGS = 500 / 600mW these SMDs have I = 1.2mA VGS = 850mW.
    Now I just have to think, in a cool drawing for the box.
    Thanks, and Good Pedals !!