What are the solutions to the buzzing sound of power amplifier transformers

In audio systems, the buzzing sound generated by amplifier transformers is a common issue that affects sound quality. This buzzing sound may be caused by various factors, including electromagnetic interference, wiring problems, insufficient filtering circuits, component aging, and vibration of the transformer itself. This article aims to explore in depth the causes of the buzzing sound in power amplifier transformers and provide a series of efficient and practical solutions.

1、 The cause of buzzing sound

Electromagnetic interference:

The leakage of the power amplifier transformer may cause electromagnetic interference, resulting in buzzing sound.

Stray electromagnetic waves may also cause interference to power amplifier circuits, leading to buzzing sounds.

Wiring issues:

Loose or broken wiring, or contact with the amplifier casing, may cause unstable current and produce buzzing sound.

Low quality wires or improper wiring methods may also cause noise.

Insufficient filtering circuit:

Insufficient capacity or poor filtering effect of the filtering capacitor cannot effectively suppress AC sound, resulting in buzzing sound.

Component aging:

Aging of components such as amplifier diodes and potentiometers may lead to performance degradation and cause buzzing sounds.

Loose or poorly painted transformer cores may also cause vibration and buzzing sounds.

Transformer vibration:

Transformer core vibration, coil vibration, or harmonic interference from the power grid can all produce humming sounds.

2、 Efficient solution

Installation of shielding cover:

Install an iron shielding cover on the power transformer and ensure it is grounded to block magnetic leakage interference.

The shielding cover should be made of iron material as it has a better shielding effect on magnetic fields.

Check and optimize wiring:

Ensure that all wiring is tight and not loose, and avoid using tied wires.

Use high-quality wires and ensure a secure connection at the joints.

Regularly check whether the wiring is worn or aged, and replace it in a timely manner.

Improve the filtering circuit:

Check if the capacity of the filtering capacitor is normal, and replace or parallel capacitors with the same capacity if necessary.

Parallel ceramic capacitors are connected to diodes in rectifier circuits to enhance filtering performance.

Correct grounding:

Ensure good grounding of the amplifier circuit and casing to avoid buzzing caused by poor grounding.

The shielding layer of the shielded wire from the audio input socket to the amplifier input terminal should be grounded at one end to avoid transmitting audio signals through the shielding layer.

Reduce transformer vibration:

Perform vibration isolation treatment on transformers, such as installing polymer damping air energy shock absorbers.

Check if the transformer iron core is loose, and if necessary, perform paint immersion treatment.

Use auxiliary devices:

Use high-power isolation transformers, regenerative power sources, or IFI branded DC Blocker+and other auxiliary devices to reduce harmonic interference in the power grid.

Check and replace aging components:

Regularly check whether the amplifier diode, potentiometer and other components are aging or damaged, and replace them in a timely manner.

Optimize circuit design:

Add filtering decoupling capacitors on the circuit board and use capacitors of different capacities in parallel.

Ensure that one point is grounded and the junction point is at the negative pole of the large electrolytic capacitor