This is a Sunn Model T preamp section in pedal form. A lot of people would probably think of this as a doom/sludge metal pedal, and while it definitely does do that (particularly with a Rat into it, which I tried because, well you have to don’t you?) it also provides a nice overdrive into a clean amp. I put the boost section on a foot switch to give me a pseudo two channel amp. Enjoying it so far! The PCB came from Benoit at Coda Effects - https://www.coda-effects.com/p/black-hole-pcb.html?m=1 Check out his site, this was a straightforward build and his documentation goes into more depth than some other PCB sites so good for beginners!
I did a reverse etch for this one with usual NaOH base solution, sprayed black and then coated with this awesome hologram glitter spray I found, gives it a cosmic vibe!