I modded my JCM800 to JEL Friedman specs (see Headfirst Amplification's channel for a how-to) and tried a bunch of different options. I ended up putting the gain boost on a switch as well as the bright cap. It now sounds great.
In this track, the 800 is on the left & is boosed with an SD-1.
On the right is my Mesa Boogie Mark IV rev b.
Together they make the best rock guitar tone I've ever been able to achieve.
Both amps were reamped using a Boss Waza TAE on LO/LO using a Palmer Dicapo reamp box, through a Focusrite 18i8 interface. No post eq or gating was applied, hence the noise. A PRS SC245 with 58/08's is in the Marshall, and an Ibanez RG550 with Fishman Modern Fluence pickups into the Mark IV.
Tune was written by Lasse Lammert.