My opinion on this (note the operative word "opinion"), is that the designer of this has a background in digital semiconductors, has probably read Don Lancaster's books TTL and CMOS Cookbooks, has breadboarded numerous blinking LED projects with a CMOS flipflop, but has minimal experience with tubes, especially musical applications.
What's the deal with all these .01uf caps? This isn't a digital switching circuit. Does the designer know what the cathode bypass cap does? (controls gain, not bypass noise).
Look at the power supply, I bet this thing hums like crazy.
This is a simple chaining of gain stages to overdrive the signal and get distortion with no thought of shaping the signal. My guess is that this thing sounds muddy and really farts out. I doubt if the gain controls can be turned up to anything more than 2 or 3.
Once again, my opinion, build this thing as is and it will go in the recycle bin for parts.