This head consists of two preamp channels. The a-channel can be switched either to Matchless DC30 or VOX AC30 mode. The b-channel including one EF86 is modified from the Matchless circuit.  A second model of this concept has only two inputs that can be switched together by using a panel switch or foot pedal. Furthermore there is a boost switch that can also be operated by a foot pedal. Actually there are 4 different amps in one box: VOX AC30, Matchless DC30, VOX AC15 and Matchless Lightning.

H30m is aimed not only at the tradiotional Brittish sound but also for a heavy Rock.

Technical data:

Inputs: a-channel High/Low
b-channel High/Low 
a-channel power amp IN
b-channel power amp IN
Outputs: 16 and 8 Ohm
a-channel preamp OUT
b-channel preamp OUT
Controls: DC30/AC30 mode switch (a-channel)
Gain Bass Treble (a-channel)
Gain Bass Treble (b-channel)
Low/High power switch
Master VOL
Stand-by switch
Rectifier: Semiconductor diodes
Tubes: 1 x EF86, 3 x 12AX7, 4 x EL84
Speaker: 12" Eminence Red Fang Alnico (separate cabinet)
Schematics: PowerSupply
PreAmp
PowerAmp
Schematics: PowerSupply
Two input PreAmp
model PowerAmp
Speaker: 2 x 10" Eminence Alnico (separate cabinet)