Audio Space Biasing for MP-1B Instruction Manual
For MP-1B
Bias Adjustment Procedure:
Be sure to adjust the volume to the lowest position before turning on the amplifier. When you’
re sure
the connections are right, turn it on by turning the power button, then the indication lamp will light up,
then wait for about 5 minutes. Connect the test lead of DC.V meter (or multi-meter ) to the (V1)terminal.
Adjust the (V1) Bias Pot to measure the DC. Voltage around 0.6V (that means the static current is around
60mA for V1), and do the same procedure for (V2). Repeat the adjustment on the both of the V1 and
V2 Bias Pots .
Hum Balancer Adjustment Procedure:
Be sure to adjust the volume to the lowest position before turning on the amplifier. When you’
re sure
the connections are right, turn it on by turning the power button, then the indication lamp will light up,
then wait for about 10 minutes. Connect the test lead of OSC Scope, VTVM or a Stereo Headphone to the
output terminal. Adjust the (V1) Hum Balancer Pot to measure the Hum noise to minimum level, and do
the same procedure for the (V2). Repeat the adjustment on the both of the (V1) and (V2) Hum Balancer
Pots .
*Note:
1. While adjustment proceeding don’
t input any signal to this amplifier.
2. After adjustment, please wait for about 10-20 minutes and re-check again as the same level of (V1) and
(V2).
3. Never insert other unknowable tubes or poor quality tubes to the sockets of this Amplifier.
For MP-1K
Bias Adjustment Procedure:
Be sure to adjust the volume to the lowest position before turning on the amplifier. When you’
re sure
the connections are right, turn it on by turning the power button, then the indication lamp will light up,
then wait for about 5 minutes. Connect the test lead of DC.V meter (or multi-meter ) to the (V1)terminal.
Adjust the (V1) Bias Pot to measure the DC. Voltage around 0.35V (that means the static current is around
35mA for V1), and do the same procedure for (V2). Repeat the adjustment on the both of the (V1) and
(V2) Bias Pots .
*Note:
1. While adjustment proceeding don’
t input any signal to this amplifier.
2. After adjustment, please wait for about 10-20 minutes and re-check again as the same level of (V1) and
(V2).
3. Never insert other unknowable tubes or poor quality tubes to the sockets of this Amplifier.