Marshall, Impedance and Modeswitch, JCM900 Series

Marshall, Impedance and Modeswitch (HIGH-LOW, PENTODE-TRIODE), , JCM900 Series: High Gain Dual Reverb and 4100, 4101, 4102, 4500, 4501, 4502, 2100SL-X, also used in the JCM2000 Series (DSL50/100, TSL50/100 etc.)