I build this Distort-o-Matic XI a few months ago. It had a few problems. I got it out and tried to solve some of the issues. I’m working on a new PCB. I ordered the original PCBs from PCBWay.com. They have a special deal for prototyping, you get 5 or 10 boards for $5. Since it costs the same I always order 10! Which means I have 9 mores boards left over. I hate to let these go to waste.
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/04/2E74CCD1-78D2-4281-90FB-379EB459C549-scaled.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/04/9C2392D6-F72D-433A-A4CB-F66C89C0A6F4-scaled.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/04/E05E7E5F-550B-4002-906A-D1AAA7239B44-scaled.jpeg?resize=1440%2C1920)
Even though there are some imperfections I thought I could get this board to work better and make a few improvements.
First the “Bias” pot should have been a trimmer. I found a funky old trimmer that fit the footprint of the pot on the PCB if I bent the legs a little. The enclosure still has the hole for the pot but this enclosure already had some extra holes.
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There was a lot of noise. The original circuit had no power supply filtering! There was no room to add this to the PCB. I took an old 100n cap and soldered it across the legs of a 100µ cap. Then soldered this across the DC power jack. This cleared up a lot of the noise.
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/06/9FF6F992-AB61-4D97-946F-ED2873170C0B.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/06/D53BA7F2-CE25-423F-B37A-F080241F3C6F.jpeg?resize=1440%2C1920)
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/06/E445451C-4FDC-4209-AE77-B4EA6EF3C7DC.jpeg?resize=1440%2C1920)
It’s a little ugly inside the box but the noise is gone and bias pot is now an internal trimmer.
![](https://i0.wp.com/www.super-freq.com/wp-content/uploads/2022/06/CA4754D8-BA3E-428E-927C-EEFFAE8A3498.jpeg?resize=1440%2C1920)
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