(Tube Complement)
V1- 12AX7, Input stage & Gain
V2- 12AX7, Overdrive stage
V3- 12AX7, Reverb Driver
V4- 12AX7, Mixing amplifier
V5- 12AX7. Phase Inverter
V6- 12AX7WA, Tremolo Circuit
V7- V8- 6L6WGC-STR, Output
V9- V10- 5AR4, Dual Tube Rect
Each fine production tube is tested and matched to our exacting specifications. External bias
adjustment and test points are located on the chassis near the output tube sockets. A digital
voltmeter and small screwdriver are required for bias adjustment.
BIAS ADJUSTMENTS:
Power up unit and connect proper speaker load.
Set master volumes and effects return controls to zero.
DO NOT
apply any signal to the input during the biasing procedure!
Take unit off standby and allow a few seconds for the circuit to stabilize.
Set voltmeter to Millivolt scale (or lowest volt scale 60 millivolts=.060 volts.)
With meter grounded to chassis and + probe at test point, measure voltage.
A reading of 0.064 to 0.070 volts is normal for 50 Watt amplifiers wi
th (2) 6L6’s. A reading of 0.12
to 0.13
volts is normal for 100 Watt amplifiers with (4) 6L6’s. If not in this range, adjust by turning
bias screw SLOWLY a small amount.
Do not set above .070,
doing so can cause tube failure in
some brands.
Keep in mind that tubes vary in quality, and some tubes can handle upwards of 40 ma each (a
reading at the test point of .080!) However, to be on the safe side, use the above as a guide.
WARNING!
No user serviceable parts inside! Refer to qualified service person only.
LINE CORD- For your safety, connect to grounded A/C receptacle only.
Summary of Contents for Two-Rock
Page 1: ...OWNERS MANUAL...
Page 10: ......
