Hetfield's 72 Seasons rhythm tone marks a return to a tighter, more focused crunch than the Black Album wall-of-mids. Greg Fidelman's production notes and subsequent Guitar World / MusicRadar coverage attribute this in part to a Jose-modded Marshall in a four-amp blend alongside the more publicized signature ESP gear. Per Fidelman's MusicRadar interview, the 72 Seasons blend is: the José-modded Marshall + a Mesa/Boogie Mark IIC++ + a Diezel + a Plexi-style Wizard — Soldano is NOT in the 72 Seasons four-amp blend.
Why this is interesting historically: Hetfield's main rhythm amps across his career have been Mesa/Boogie Mark-series (the Mark IIC+ defines the Master of Puppets / …And Justice for All era, acquired late 1984 / early 1985 after the Elektra advance; later a Mark IV and Mark V join the rig). The Jose-modded Marshall entered Hetfield's signal chain on the Black Album (1991) via producer Bob Rock: Rock got Mick Mars's amp-tech (Jose) contact info specifically because of the Dr. Feelgood tone, commissioned his own Jose-modded Marshall, and brought THAT amp into the Black Album sessions for Hetfield to use (documented in metallicagearhistory.com's "Asshole Marshall" feature). So the Jose-modded-Marshall thread in Hetfield's rig runs Black Album → Load / Reload → Death Magnetic → 72 Seasons via Bob Rock's commissioning, not via direct contact between Hetfield and Jose.
Note on Mike Soldano (per the prior version of this entry): Soldano is sometimes incorrectly listed in Hetfield's gear lineage — comprehensive gear-tracking coverage (Ground Guitar) shows no Soldano SLO-100 in Hetfield's published rig for any album. The Jose-Marshall / Mark IIC+ / Mark IV / IIC++ / Diezel / Wizard combinations are what's documented. Soldano himself is a parallel-tradition West-Coast modder (Seattle origin, moved to LA early-to-mid 80s, launched the SLO-100 commercially in 1987) but his amps don't appear in the Hetfield record.
The mods that likely matter for this tone, in order (the specific component-level modifications on Hetfield's 72 Seasons head are not in the published Guitar World coverage, so the list below is informed-guess based on the broader Jose-mod canon and what the rhythm tone sounds like — treat as plausible recipe rather than confirmed teardown):
1. Bright-cap reduction — Hetfield runs the gain knob hot, and a stock 5nF bright cap on a hot Plexi/2203 is ear-piercing in the top end. Reducing or removing it tames the fizz and lets the tone-stack treble do real work. 2. Jose Master Volume — the pre-tone-stack location preserves low-end at the stage-volume settings he runs. 3. NFB looseness — the open-loop bloom in the upper-mids is what gives Metallica rhythm parts that "glow" around the riff. Without it, the tone is too clinical. 4. Cascade V1→V2 — the gain headroom needed for the bridge-pickup detuned-down-to-Eb riffs.
JMIL surface area: approximate Hetfield 72 Seasons by starting from the Stock 2203 chassis (or Plexi if you prefer), enable bright-cap reduction + Jose MV + NFB mod + cascade. Skip the diode clipping — Hetfield's 72 Seasons crunch is not diode-shelf compressed, it's preamp-tube-clipped with NFB loosened. Dial Mid ~6, Treble ~5, Presence ~7. The "JCM800 Jose" preset is the closest starting point.