hi. This is going to be my first creation from scratch. I'm going for the green russian big muff clone. I tried to order the most high end parts from small bear. (NOT EASY) I got some of those high voltage caps (yellow looks like dipped in rubber.) can I use these in the circuit or do I need ceramix?
as long as it's above the operating conditions, you're good, even if they're way above.
I've seen a few documents that say originals use ceramics, which is true for most of them. I've only done it once and the results were very similar. The biggest difference w/ the ceramics is they were out of tolerance so that exact Big Muff was a bit more treble-y (the coupling caps were slightly lower).