a few things ....
Eds pickup had the front coil shorted from fan picking and the high e getting stuck with deep dives
Suhr claims a jack on the back panel was to 'lift the power tube cathodes' ? WTF
Whats a few stock Marshall parts amongst friends
Actually , my origional 12 series has been from stock clean and mean to full blown Harry Kolbe modfest . It sounded killer to start but the mod was for EVH . He added a separate high voltage power supply . Mostly the later 69 set up , but leaving the existing filters . So 50uf cans . And put the preamp on high voltage too . He had a stock input and his preamp mod . It consisted of a bi fet pre amp and the mod leadguy just outlined . Hey it sounded very versitile . It also had the Jose Mod cause Kolbe knew the guy . I thought it was bullshit cause I heard the same mod in a perfectly good sounding JCM800 and it ruined it .
My 12 series however , just sounded killer . One day I went to buy a 69 Super Trem from a guy who didn't have stock Marshall Cabs . He plugged into mine and it was the best tone ever . Imagine Dirty Movies through two cabs just dancing on the floor . He wouldn't sell it . He kept it . Fucker .
I say that because I restored the Plexi to stock specs and then to Cerrum specs and it kills no matter what. Not as much variation as you would think . Even with the variac . Food for thought though .
I do hear Ed using a second variac . I've said it before . I've used it in between the amp and the speaker and it gives a volume reduction and a shimmer that is just like 'Push come shove' . NO harminizer . It may have been a factor turning him on to the harmonizer . He just used it initially at 10ms for a fatness and early stereo testing with the RIPLEY ! woo hoo
BUT , you guys miss the most important fact I have been talking about for years now .
The transformer Ed prefers is the later BIG 69 OUTPUT . He favors it for the volume the grind and the harmonics galore !
In the 12 series the magnetics are now completely a factor . Affecting the caps under it and the circuit becomes more of an enigma . Oh and don't forget the choke ! For a reason .
All the mods you guys are talking of are cool and standard mod tweaks , but all of which can be tweaked with an EQ up front .
What year did Jose Die ? Thats a big deal on the timeline .