If and when I get to it, sure, I can post it here as it is related. Not much of a difference in the circuit topography considering the tube chain. Drive circuit is identical but does not have a C39 counterpart on the V4 circuit (based on a IIC+ schematic). After owning and operating the JP-2C for a while, it seems like the fundamental tone still sits in the darker side of the Mark Series, very similar to the Mark III blue stripe I had. Huge difference on the channel volume, a setting at noon is like the Mark III set to "3 or 4". Sure the amp can be dialed it to be abusively bright but does lack the ice pick characteristic as I have yet to experience the broken glass effect in the eardrums like I was getting with the Mark V on CH3 before the 12AT7 discovery of this thread. Not exactly sure what the actual differences are in circuit design as I have not viewed my eyes on a JP-2C schematic (only reference is a an old IIC+ hand drawn sketch of the amp so I will not take that as a blue print for the JP-2C in its entirety.)