I built a P19 version of the Big Muff - based on Juansolo's spreadsheet, and used BC550 tansistors. I have been trying for about three months to figure out why it wont work - it gives a bit of a volumeboost/ very subtle overdrive but no muff-ness.
I was reading on the net lat night about muff variants - I think it was GGG - about being carefull with making sure the pinouts on transistors are correct. So of course (hand slap to forehead) , I look at an on-line spec sheet and sure enough, the 550s are 180 degrees reversed from a 2N5089 and the like. So last night I flipped them around and BAM!!!! muffy, muffy goodness.
So pleased that this one finally works.
Barry
Good to know. I'm planning to build a P19 soon.
I compared it side by side to the Violet Rams Head version of the Mudbunny I built last year - the P19 sounds clearer and a bit brighter to my ear.
Next up for me is a Green Russian Version of the Mudbunny (Im looking for that Black Keys tone) - and a Pharoah PCB (the King Tut) that I bought from Rullywow.