The Solstice Amp Distortion is a recreation of the Marshall Shredmaster, first released in 1991 alongside the Bluesbreaker and the Guv’nor, which was previously released in 1988 as the Drivemaster.
Despite its name, the Shredmaster is not an ultra-gain metal monster like the Boss Metal Zone. Unlike the Guv’nor, it does have the ability to scoop the mids, so you can get some sounds out of it that approach the metal territory—but for the most part, the name is misleading.
The Shredmaster has a lot in common with the Guv’nor / Drivemaster, and in fact the first half of both circuits are nearly identical. However, the Shredmaster has an additional gain recovery stage, and even though the three tone knobs appear to be the same on the outside, the tone stack is very different.
The Solstice is faithful to the original, but with one added modification: a switch that lets you go between different clipping diodes. The original has a pretty low clipping threshold with just one 1N914 diode in each direction, meaning its clipping character is more gainy and compressed. But some different sounds can be coaxed out of it if you stack two additional diodes (as in the Bluesbreaker) or use LEDs (as in the Guv’nor) to get a higher threshold.