The Blackstar is a high gain distortion pedal especially suited for hard rock and heavy metal playing. The Blackstar allows you to match the pedal to your guitar and amp… NOT the other way around. Most high gain pedals fall flat because of their frequency response, or because all the distortion is produced in one gain stage.
Frequency response problems can happen at the input or output of the effect. Too much bass response at the input can make the distortion muddy. Of course bass response is dependant on the guitar used, and most distortion pedals do not allow for tweaking pre-gain bass response. The lower drive knob is a bass frequency gain control and allows you to “match” the pedal to your guitar. Then there’s the output. A lot of high gain pedals sound great at low volumes, but just don’t cut through the mix at rehearsal or on stage. The Blackstars’ tone control allows you to match the distortion to your amp, whether its a 1×10 combo, or a 4×12 stack.
The Blackstar produces its distortion through cascaded gain stages, much like a tube amp. Each stage is a little different. The first stage uses a mosfet. The two following stages use hand picked jfets. Jfets are known for producing even harmonics when overdriven, much like tubes in guitar amps.