The Olde Dirty Bass is the overdrive sister pedal to the Volt Thrower distortion. Like the Volt Thrower it utilizes the same internal voltage conversion which will allow up to +-18V operation if an 18V supply is used. Increased supply voltage allows for larger output voltage swing and improved headroom.
The circuit is derived from a OCD but like the Volt Thrower scraps most of the circuit after the clipping diodes and uses the same Bass and Treble EQ as in the Volt Thrower. However, an added Mid Boost control was included to increase the flexiblity of the EQ. Also like the Volt Thrower, the pedal was conceived to be a bass-friendly design.
There are 2 top mounted toggle switches which can control the clipping diode arrangement (LED/MOSFET) and the input low shelf (controls the low end RC cutoff of the first gain stage). The input low shelf helps to tailor the amount of low end reduction early in the circuit.