(Tube Complement)
V1- 12AX7, Rhythm channel
V2- 12AX7, Lead Channel
V3- 5751/12AT7, Reverb Driver
V4- 12AX7, Reverb/effects
V5- 12AX7. Phase Inverter
V6, V7- 6V6GC/6L6GC, Output
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 0.055 to 0.060 volts is normal for 50 Watt amplifiers with (2) 6L6’s. A reading of 0.115
to 0.120
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!
For other tube types (5881, 6550, EL34) check with the manufacturer or contact us for
recommendations.
Settings higher than .065 with 6L6 tubes may cause premature tube wear and possibly damage
the amplifier.
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.
NOTE:
Some amps are equipped with 2 bias pots, one for low power, and the other for high
power. Adjust bias in both hi and low power settings!
NOTE:
Some amps are Class A/AB. In LOW POWER MODE (CLASS A), you will not get a proper
reading- adjust bias in high power mode only.
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 Jet Signature
Page 1: ...OWNERS MANUAL...
