I had built he UBE Screamer years ago. Great idea, thanks RunOffGroove! It had this strong out of phase flavor in the sound. I made up a new version where used the extra inverter to invert the input signal that gets mixed with the output.
(https://i.postimg.cc/Hj7pks16/IMG-2867.png) (https://postimg.cc/Hj7pks16)
Here is a link to a post with some more pictures and notes. http://www.super-freq.com/ube-screamer-v2-2/
Thanks for the updated schematic. The UBE Screamer was one of my first vero builds. I liked the overdrive tones but I noticed it seemed to be a tad noisy at high gain levels. Do you notice this as well? Also, with your mod, does this sound more mid focused versus the original? Anyhow, I'll have to try it out on my breadboard - I have a good number of CD4049UBE chips in my parts bin. :)
The sound is similar. The difference isn't great but noticeable. I suspect there is enough phase shift from the distortion and filter sections that the out of phase from the buffer isn't as strong as it could be.
The trimmer between the input buffer and the ouput buffer has a greater impact on amount of distortion and over drive you can get.