See diagram above for location of bias trimmers and test points
4-Aces: Set bias controls for .020 volts on each test point (20-Ma per 6SN7 Class AB-1)
Lucky-7: Set for .05 volts on one test point (50-Ma for single EL-34 Class-A)
Blackjack-21: Set for .02 volts on each test point (20-Ma per tube Class-AB-1)
Full-House-50: Set for .036 volts on each test point (36 ma per tube Class AB-1)
PREAMP TUBES AND THEIR FUNCTIONS:
V-1 12AX7 (nearest to input jack). Main input preamp, first clean and overdrive preamp
(premium tube recommended)
V-2 12AX7 (middle tube) Overdrive only preamp.
V-3 12AT7 Phase inverter/driver tube
4
Front Panel Controls, inputs & Their Functions
Input Jack:
Input jack is a 1/4" phone plug, designed for 1-Meg impedance, guitar-level signal. This
input will readily accept pedals/effects without any loss in performance. Pedals/effects
input is also inserted to this input in series with your guitar.
Clean Gain Control:
The gain control sets the overall gain/volume for the amplifier in the clean (channel-1)
mode. Adjust to volume /tone taste.
High Control:
Adjust the high control to taste, it controls adjusts the high frequency spectrum of your
amplifier.
Mid Control:
Adjust the Mid control to taste, it controls adjusts the mid frequency spectrum of your
amplifier.
Low Control:
Adjust the Low control to taste, it adjusts the low frequency spectrum of your amplifier.
OD-Gain:
The OD-gain control sets the amount of drive in the gain channel. This channel is
accessed by the left footswitch button, or by pulling the Overdrive Master control knob
out. This control will adjust how much gain and distortion you will have in channel-2.
OD-Master:
The OD-Master controls the volume of the amp in channel-2 (overdrive) mode. The
Overdrive gain (above) sets the amount of distortion, and the Overdrive master sets the
volume at which the drive channel operates.
