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.

Thursday, July 18, 2019

Fulltone OCD V2

The latest iteration of the OCD has quite a few differences from the earlier models. There's an added transistor stage at the output after the volume control, and a JFET buffer that can be toggled for buffered or true bypass. I've laid it out so it will still fit in a 1590B with board mounted pots.






The off-board wiring's not the most intuitive, so here's a diagram for wiring up the buffer switch and 3PDT bypass footswitch.

14 comments:

  1. https://www.youtube.com/watch?v=h3uBr0CCm58

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  2. When looking at the On Semiconductor datasheet I think you need to rotate the 2N5457 180 degrees. So always check your transistor pinout before soldering :)

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  3. Checked! Sounds beautifully, it took a little work to finish, many wires to solder, I made a small change to be able to switch between clipping the 2n7000 and some red LEDs, there is a small change in the sound but I still don't know if it's worth it. Thanks for more this great layout!

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  4. I have slight overdrive, when i use buffer. Without (direct) buffer - clear signal. Is anybody have same problem? Used 2n5457 transistors.

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    1. Yes, same problem here. I tried some 2n5458, and J201 it is working little bit better (louder). On true bypass there is no problem. Will try some SMD versions of 2n5457... think, i might have some "fake" out of specs 2n5457...

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    2. I just try mmbf5457 on adapter, works perfect with them... no volume loss at all on buffered mod... just pickup up some good 2n5457 or SMD version... ;-)

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  5. hi everyone, i did this great pedal and it works well but I feel it needs a little more definition in the high end, sharpen the sound a little bit. Do you think this could be due to bad 2N5457 ICs ? thanks.

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    Replies
    1. Not likely to be semiconductors. You may just need to adjust some cap values to taste.

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