Solid state preamp and valve power section (cathode biased). Two channels. A JMI design (Derek Underdown).
VALVES: ECC83 driver and 4 x EL84. Around 30W output.
VIBRATO CHANNEL: volume, bass, middle, treble; vibrato speed and depth. Treble boost.
NORMAL CHANNEL: volume, treble, middle, bass; and reverb depth. Mid boost.
EFFECTS: vibrato, reverb and distortion (preset) switched on or off via a footswitch.
SPEAKER CABINET: 2 x 12″ open-backed cabinet normally containing two Celestion alnico silver drivers (T1088 with doping to aid power handling). Swivel trolley.
Used by the Beatles on Sgt. Pepper. Also used by Joy Division / New Order.