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, August 3, 2015

Super OCD

I stumbled across the schematic for this a while ago and have been meaning to lay it out for a while. It's Fred Brigg's souped up version of the Fulltone OCD. Here's what he had to say about it over on his blog:

The "Super OCD" has a few extra controls:

- Firstly the "Bass" control - it's nicked from Paul C's Timmy pedal and works very well to add in pregain bass for more low end response.

- Secondly the "Saturation" control, this allows you to increase the clipping headroom of the circuit and have an overall "cleaner" tone while dialling in just the required amount of diode clipping.

- Thirdly the "Boost" control, I've configured the second opamp to allow a range of clean boosts to be selected to really allow you to push the front end of your amp into overdrive.

- The final control I've added is a switch to go between 9 volt and 18 volt operation. The 18 volt operation adds extra headroom to the circuit to stop the opamp clipping from fogging up the tone. The 9 volt operation retains the original headroom seen in the OCD.

- Other changes include alterations to the Tone control and a swap of opamp from the TL082 in the original OCD to the Burr Brown OPA2134. These changes all add up to create a really nice overdrive/distortion box. It's got all the original Fulltone OCD tones in there and loads more. If you like the original OCD you'll love the Super OCD.

I've laid this out for board mounted pots (from the solder-side with right angle PCB pots) and it should fit in a 1590B. (Though when I build this thing, it's definitely going in a 125B haha)


EDIT: Forgot to include what Q1-2 are–like in the original OCD, use 2N7000 MOSFETs.

10 comments:

  1. Hai, thanks for this great layout. I had built and working well. I'm curious, has anyone compare it with the original fulltone OCD? I watched youtube demo and it seems not so much gain as I found my build is very high gain. Before build super OCD, I also built OCD v3 on veroboard and very high gain.

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  4. Did anyone experiment with the variable values? the 10-15k resistor and 22-68nf cap?

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    1. its really dark so if i were you i would use 10k,22nf and lower the 100pf caps as well

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    2. You're right this thing is dark, I went with the 22nf but I think I still have a 12k where the 10k should be. I had to put a buffer in front of it to stop it squealing too.

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  5. anyone have a drill template? Please and thank you!

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