Top Panel
9
3.
4.
V1
、
V2
、
V3
:
5BK7A
5.
Used to select Triode/Ultralinear working state.
TR:Triode Operation State;
UL: Ultralinear Operation State.
1.
2.
A1
、
A2
、
A3
、
A4
:
EL34
Bias Adjustment Knob for
Power Tubes
(A1
、
A2
、
A3
、
A4)
Bias Selector Switch
(
A1
、
A2
、
A3
、
A4)
Used to select corresponding tube for bias
adjustment.
Triode/ Ultralinear Indicator
◆
Be careful of the high temperature of the tubes during operation.
◆
Replace the tubes carefully and correctly.
◆
Power tubes must be matched for well function.
NOTE
Diagram 3
Diagram 5
Bias meter during working
Note: When working normally,
the pointer should stay within
the A zone, still , it would move
for the voltage fluctuation.
Diagram 4
Bias meter when not working
A
Bias adjustment for the power tube:
Turn the BIAS SELECTOR Switch to the power tube you
are preparing to adjust. Adjust the corresponding BIAS
ADJ. small knobs with flat screwdriver, and inspect the
BIAS meter on the top panel and make sure the
pointerkeeps in the center. Bias adjustment for A1, A2,
A3, and A4 are the same. After all have been adjusted,
do it one more time, to make sure all the bias level of A1,
A2, A3, and A4 are the same.
Sample of Bias adjustment for power tube A1:
1. Turn the BIAS SELECTOR Switch to A1;
2. Turn the BIAS ADJ. knob A1, until the pointer of the
bias meter keeps in the center.
The same for A2, A3, A4.
A
1
A
2
A
3
A
4
B I A S A D J
.
A
2
A
1
B I A S A D J
.
A
3
A
4
P O W E R T R A N S F O R M E R
O U T P U T T R A N S F O R M E R
WIDE
FREQUENCY
RESPONSE
O U T P U T T R A N S F O R M E R
WIDE
FREQUENCY
RESPONSE
B I A S S E L
.
B I A S S E L
.
T R
U L
A
3
A
4
A
1
A
2
V
1 5
B K
7
A
V
3 5
B K
7
A
T R
U L S E L
.
V
2 5
B K
7
A
1
1
2
2
3
3
4
4
5
4
