We select premium vacuum tube components. All vacuum tubes undergo rigorous testing. We measure core parameters including filament stability, transconductance and internal resistance, conduct long-duration burn-in tests, simulate static and dynamic operating conditions, and carry out channel matching screening. Tubes with excessive noise, parameter dispersion or poor operating characteristics are eliminated. Precision matching ensures channel balance for push-pull circuits and suppresses crossover distortion. Reliable vacuum tubes deliver rich, fatigue-free tone while lowering failure risks, laying a solid foundation for long-term stable operation of the amplifier.

Proper bias adjustment enables all power tubes to operate at their optimal working point, which directly affects the sonic performance and service life of vacuum tubes.Line Magnetic tube amplifiers feature bias control knobs on the front panel. Users can monitor the operating status of power tubes via the meter and perform adjustments as required following the instructions.

Adjustment Procedures

1. Toggle the selector switch to choose the vacuum tube to be adjusted (marked V1, V2, V3, V4). Hold the switch in position during adjustment.
2. Slowly turn the adjustment knob with a suitable screwdriver.
3. Watch the bias meter while adjusting. Stop turning once the pointer reaches the optimal position.

Two Common Mistakes During Bias Adjustment

1. The amplifier requires sufficient warm-up. Bias readings are unstable during startup and warm-up. Carry out accurate adjustment only after the unit reaches stable operating conditions.
2. Turn the knob gently with the screwdriver. Do not apply excessive force when rotating clockwise or counterclockwise, otherwise damage may occur.