1992 Marshall JCM 900 Model 4100 Dual Reverb - 100W Hi Gain Master Volume MK III Head - All Original - Brett Allen Studio Rental Collection

Condition: Very Good Includes: Marshall JCM 900 Model 4100 100W head, Danny Ghinn service report (no footswitch) Serial: Z02937

Overview The Marshall JCM 900 Model 4100 Dual Reverb is the 100-watt, two-channel, footswitchable Master Volume head Marshall introduced in 1990 as the successor to the JCM 800. It delivered higher gain than the 800 series with independent footswitchable reverb on both channels and became a staple of late-80s/early-90s rock and metal. This 1992 example is confirmed by Danny Ghinn as all original with no modifications — an increasingly rare condition for these amps, which were typically gigged hard and often re-capped or re-tubed without documentation. Black Tolex with gold piping, gold control panel, Marshall script logo. Single footswitch (not included) controls channel switching and reverb. From the Brett Allen Studio Rental collection.

Key Details

• Format: Head
• Year: 1992 (dated by Ghinn)
• Make: Marshall
• Model: JCM 900 Model 4100 Dual Reverb / 100W Hi Gain Master Volume MK III
• Power: 100 watts (switchable to 50 watts via pentode/triode switch)
• Channels: 2 (footswitchable)
• Reverb: Dual independent reverb (one per channel)
• Tubes (standard 4100 complement): 4x EL34 power, 4x ECC83/12AX7 preamp
• Originality: All original, no modifications per Ghinn inspection
• Front Panel: Presence, Bass, Middle, Treble, Master Volume A, Master Volume B, Reverb A, Reverb B, Pre-Amp Volume, Lead Master, Lead Drive, channel select
• Rear Panel: Series effects loop, DI output, impedance selector, pentode/triode switch
• Covering: Black Tolex with gold piping
• Footswitch: Not included
• Country of Manufacture: Made in Bletchley, Milton Keynes, England
• Serial: Z02937

Service Summary Serviced by Danny Ghinn in Los Angeles on December 29, 2025. Ghinn confirmed Model 4100 designation, 100 Watt Hi Gain Dual Reverb circuit, and all-original condition with no modifications. Footswitch not present. Full service report available to the buyer.

Condition Cosmetic

• Black Tolex finish with age-appropriate wear
• Gold control panel intact with knobs and labeling clean and legible
• Marshall script logo present and intact

Functional

• Fully operational per Ghinn inspection
• Footswitch not included; buyer will need to source the Marshall PEDL-00001 (or compatible) for channel and reverb switching

Provenance From the Brett Allen Studio Rental collection.

Shipping

• Professionally packed and fully insured
• White-glove delivery available
• International shipping available

Final Notes Additional photos and Ghinn service report available on request