Marshall JMP 2203 (1980) Modified BE/HBE

Captures of my modified Marshall JMP 2203 made December 1980. The amp was modified in February 2016 by Steve Dawson, former R&D design engineer for Marshall, now of Root Two Amplification. Steve designed the : • Vintage Modern • Class 5 • JMP 1-Watt Series • Astoria Series • JMD Hybrid Series He also contributed to reissues and specialized builds, including the 1962HW Bluesbreaker, JTM45/100 and the Super100JH Jimi Hendrix amplifier. It’s a dual-channel amp that’s roughly a 95% clone of the early Friedman BE-100 BE and HBE circuits, based on the first few revisions from around 2011–2016. The main difference is the negative feedback circuit, which uses a 47k resistor from the 4-ohm tap, similar to the post-2018 BE-100. This gives it a slightly rawer, more aggressive Marshall character. It also features a depth/resonance control and a variable **Bold/Spongy** control, which acts as a variable voltage divider after the first gain stage to adjust the tightness and feel of the low end. The HBE channel adds a footswitchable fourth gain stage with its own dedicated gain control, rather than relying on a fixed gain setting as found on the BE-100. The 20V Zener diode clipping circuit is also implemented slightly differently, following the original Jose Arredondo approach more closely. Additionally, it features two footswitchable post-phase-inverter master volumes, which can be used for solo boosts or to tame the overall volume while still driving the phase inverter. The low input bypasses the first two gain stages, providing a much more familiar two-stage JCM800/JMP-style low-input response. It’s a fantastic amp, for sure. The only real omissions compared to the BE-100 are the C45 and Voice switches, although it retains the Fat switch. Key: BE = BE Channel HBE = HBE Channel SAT = Zener Diode Clipping On/Off FAT = Fat 22nF coupling cap On/Off G = Preamp Gain 1-10 B = Bass 1-10 M - Middle 1-10 T = Treble 1-10 P = Presence 1-10 MA = Master 1-10 D = Depth/Resoance 1-10