I got this one back in 2004 and used it quite a bit with my old band. The EHX Muff Fuzz is actually a pair of low gain Silicon Fuzz-Face style circuits with clipping diodes in each to smooth out the edges. Cascading two in series definitely enters the fuzz arena and you can use the two volume controls in different configurations for more/less gain and squish. I had a small mod on mine by Nicholas Kula to reduce gain in the first Muff circuit. This plays nicer with humbuckers and clears up some of the mud. Enjoy this revisit and a little nod to the original PGS demo from 2008...https://www.youtube.com/watch?v=wAVhAgTIP6g
Amp: Univox 60w Bass Head U-1246
Guitar: Yamaha SAS-II Semi Hollow with Total Gravy Early PAFs