Marshall JCM800 Series Service Manual 3.8MB. JCM-900 Series. Summary of Contents of user manual for Marshall Amplification JCM800 Series. Page 1 Marshall Amplification plc Denbigh Road, Bletchley, Milton Page 10Vintage Re-Issue Amplifiers JCM800 2203 Head • JCM900 4100 Head • 1962 'Bluesbreaker' Combo • PB100 Power Break From left JCM900 Bias Video Biasing a Marshall JCM 800 2205 with multimeter Mother of All Marshall Amp Repair Videos - DSL100 Blowing Fuses, Bias Runaway, Fun Times! So for years I have wanted a Marshall JCM 900 high gain dual reverb head, I think its the 4100 model. After reading this thread it sounds like there is some hate towards the JCM 900 line. I borrowed a 2x12 combo from a friend years ago and really liked it. Well I own a JCM900 and it can do those sounds pretty well and in my opinion is the most versatile of the 3 (hence why I bought it). I think most of the bands whose sound I like did/do use old Marshall heads and get their distortion through the amp, not effects. JCM900 4100. This two channel dual reverb 100W powerhouse will make you stand out on stage. Each of the two channels has its own gain and volume settings so that you can crank the gain in the preamp and the volume and get the true loud Marshall crunch. Valvestate I, JCM900 and JCM600 Series. Also used in the JMP1 Preamp as Output Level Control. Used in the Marshall JCM900 series amplifiers. JACK PLATE REPAIR KIT Replaces the common failure parts on the JP-800 mono/stereo jack plate (shown above) as found on the 1960A, 1960B Marshall JCM900 4100 Manual Russian.pdf. Peavey ValveKing Series Manual Russian.pdf. Marshall manuals | You will find on this page the manuals and instructions for use for musical instruments, Marshall PA Equipment, studio, lighting and sound equipment. PA systems, PA speakers, PA mixers, Powers Amp, Crossover, Microphones, Wireless Equipment.