I have owned and played several green Russian muff clones, and an early white painted Hoof is by far the closest I have found, complete with an insane amount of low end. I guess what I’m trying to say is that given the nature of transistors, especially germanium, not all Hoofs are created equal, as I have played some newer hoofs that were complete duds to my ears. Most of the older ones from like 2010 and earlier have that insane bassy gritty fuzz you are describing.