I did ROG 22/7 the other day and I instantly fell in love with it! Then I did Way Huge Red Llama and man, what a great overdrive.
So I decided to scan the net on CMOS based distortions and overdrives and stumbled on this.
CMOS DS1 Schematic
Drew a layout and built it and it sounded decent, pretty true to the original which meant I had to modify it.
Changed input and bypass caps to larger values found in the old MIJ version and swapped the silicon diodes for orange LED's. Now it's a loud and and quite evil fuzz perfect for down tuned heavy stoner rock.
Vero with stock values.
Vero with mods.
Both are verified, now I just have to add a gain control...
Thanks for doing this!. Really, sounds close to the ds-1? interesting. I like the ds-1 and have been interested in csmos designs. Any clips? Thinking ahead, how would one squeeze out more distortion? I'm sure it's plenty heavy already.
Well, not really THAT close, smoother and a bit fuzzier I would say. Still it sounds quite good.
I don't really know much about CMOS circuits but for more gain you could probably replace the 470k resistor with a higher value? Red Llama has a 1M pot in this spot. It's also worth decrease the 4,7k resistor that goes to the 470nF cap. Subbing the silicon diodes for LED's really make it more aggressive and heavier.
Interesting design! Another thing you may want to play with in this circuit is the supply voltage to the CD4049UBE. Generally, they like it around 5 - 6V, so instead of the the 10 ohm resistor in series (first layout) with the 9V input power, I would try 220 or 330 ohms (which you have in the second). The Red Llama uses 1K!.