James Hetfield.
Dude is super secretive about what he uses and guards the particulars of what he does very closely. At first glance, hearing his general cadence about this kind of thing almost makes it seem like he avoids gear talk because he's not a gearhead and doesn't care, like he just wants "some good high gain shit" and that's as deep as he goes while letting his techs do everything else, but I think he knows exactly what he's doing and what he wants out of his tone, but refuses to talk about how he actually gets it. Almost every detail we actually know about his sound comes from other people who have worked with him, and most of them usually avoid going into any real detail "out of respect for James."