I was staring at the schematic contemplating Lyle's mods...when I realized there's something else to fix. I used to wonder why the Class 5 sounded darker when using the headphone output (headphone trick or low power switch). Turns out Marshall put a cap to ground (C50) on the attenuator circuit to make the output less shrill on headphones. If you remove C50 or R51 (R51 is easier to remove), the attenuated output now sounds more like the base tone of the amp. Easier to just remove R51. Everyone who uses the "headphone trick" should do this imo.