This is interesting variation on the Tube Screamer style diode clipping. Read more about it at Mark Hammers site here: https://hammer.ampage.org/files/The_Crank.gif
In a nutshell the goal seems to be less distortion. More of a booster to overdrive effect. I’d say this circuit meets that goal. The sound is mostly clean with some gravel or grit as you get louder. It never gets fully distorted.
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/04/the-crank-schematic.png?resize=1300%2C1030)
The Build
I designed the PCB in Eagle. Then had some boards manufacture at PCBWay.com. The cost was $50 for 10 boards, which is seriously cheap. The shipping costs were $20. By ganging this order with a couple other orders I kept the costs down to $1 per board. So $10 for 10 boards is better than making the boards by hand.
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/BDE3F152-94BD-48A4-A529-08A9DB8C9DF9-scaled.jpeg?resize=1440%2C1920)
Sadly I mixed up the pots so the rotation is backwards. While I could fix this by cutting the legs on the posts and soldering some jumpers, I think I I’ll just make a new version of the board in the future. There were a couple other improvements I also want to make.
I designed the board with the pots and LED mounted to the board and off board wiring at the bottom edge. This makes for a very easy build.
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/9CAAAD86-A594-4A32-8D22-CDB98B51FD54-scaled.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/E034329A-64AC-4072-9AC8-2586BD0A2A3B-scaled.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/E614EE59-B446-4604-99F9-E075A73DE667-scaled.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/A06CDD2F-76BB-4138-9996-FE8FD80FC9DD-scaled.jpeg?resize=1440%2C1920)
I designed the graphics in Sketch and milled the enclosure on my desktop mill.
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/E44A37B0-3D59-4ED6-9545-1676BA1F1B0F-scaled.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/97E78C50-66D6-4023-80E5-D143866CFBDC-scaled.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/C380B9CB-F27C-4353-994D-FA077649F859-scaled.jpeg?resize=1440%2C1920)
Last I wired everything up. With the offboard connections organized along the bottom of the board the build process is easy and prevents errors.
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/68DADEA2-E61C-4827-8B46-C410ECEB11F4-scaled.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/03/B516FD55-4335-418F-B002-B2037EA8848B-scaled.jpeg?resize=1440%2C1920)
I may publish this one to the shared service but it will need an update first to fix the pots which operate backwards.
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