A first-person historical note from Dave Friedman (Amp Panel #13, March 2026, ~[63:44]):
> *"When they first did the 900 series… there's not really the DNA in there, but they had a Jose that they were looking at. And I know this cuz I remember when they first came out and some guy from Marshall was talking about this with us."*
What this confirms and what it doesn't:
Confirms: Marshall's engineering team was aware of and physically examining Jose-modded amps during the JCM900 development (late 1980s). The Jose mod was on the radar at the Marshall factory level, not just in LA boutique circles. This pushes back against the simplification that "Marshall ignored the modder scene" — they were paying attention.
Doesn't confirm: that the JCM900's circuits are Jose-derived. Per the same Panel #13 discussion ~[66:29], Friedman pushes back explicitly: *"Marshall probably did some clipping independently because… they didn't do it in the same way that Jose did it. The way they went about it was different, and it's asymmetrical."*
The 900-series diode-clipping vs Jose's diode-clipping:
- Jose — back-to-back symmetric Zener pair across the MV wiper to ground via 10kΩ. Produces symmetric clipping. (See diode-clipping mod.)
- JCM900 (Mark III, 4100 dual-reverb) — asymmetric diode arrangement, likely derived from pedal-world precedents (MXR Distortion+, etc.) rather than Jose. Different sonic character (more "edgy," less "compressed").
- JCM900 SL-X (2100/2500) — no diode clipping at all; uses a 27kΩ plate-resistor + DC-coupled cathode-follower gain-reduction trick instead, designed by Steve Grindrod (see steve-grindrod-marshall-designer).
JMIL position: the JCM900 series sits in JMIL's adjacent-traditions space — Marshall's in-house response to the high-gain modder era. It's not Jose-school but it's not unaware-of-Jose either. The historical record (per Friedman's first-person testimony) is that Marshall examined Jose's work and then *independently* developed their own answer. Builders or players researching the lineage shouldn't claim Jose-derivation for the 900 series, but also shouldn't claim Marshall worked in isolation from the LA modder context.