The Blues Breaker was designed to emulate the vintage 2×12 Marshall combo, and was introduced by Marshall in 1991. Great at pushing a clean amp into breakup and sounds great with single coils. There has since been a Bluesbreaker II, which many claim to be inferior to the original. This layout is for the original model with onboard pots and will fit in a 1590B.
Note that the PCB layout is half a row (0.05 in/1.27mm) taller than the perf layout.