The Black Acid is a modified Fuzz Face and originally introduced in 2012 by Emanating Fist Electronics (D*A*M) which are known for making expensive boutique, great sounding pedals. The original comes in a HUGE 1590D silkscreened enclosure (7.4" x 4.7" x 1.4") and a standard 3PDT clicking bypass, but I went with a much smaller 1590B, with a distressed etching with all top jacks with a soft click relayed true bypass. These sound great with both a bass and guitar with no low end loss. The drive control varies the amount of low end entering the circuit and is very interactive with the fuzz control enabling to go from clean, to a mild overdrive, all the way to a heavy fuzz.. I used carefully selected NOS Telefunken BC109 metal can transistors in mine. I love the sound of this fuzz pedal! I am only going to be offering ONE of these for sale (the one in the picture).