ZK-502E 50W*2 High and Bass Adjustment Preamp Audio Power Amplifier Module Subwoofer Bluetooth 5.0 Dual-channel Stereo with Aluminum Shell

Q1: All the wires are connected, why the indicator light is not on?

A1: Rotate the volume switch to turn it on. If it still does not light up after turning on, check whether the power supply is connected properly and whether the positive and negative poles of the power supply are connected correctly. If everything is right, find a laptop power adapter (power supply should not exceed DC25V) or 12V battery power supply to determine whether it is a power supply problem or a product problem.

Q2: Why is the sound broken or distorted?

1). The power supply voltage is too low, the volume is adjusted too much, the power supply is insufficient, and the sound will be distorted. It is recommended to change to a high-voltage power supply or turn down the volume.

2). The power supply is sufficient, but the speaker power is too small, which will cause the speaker to overload and break the sound. It is recommended to turn down the volume or replace with a higher-power speaker.

Q3: Why does the volume knob do not move, but the sound level is different when connecting to different audio sources (such as first connecting a CD and then changing to a mobile phone)?

A3: If the volume knob is not moved, the sound magnification will not change. The amplitude of the audio signal output by different playback devices is different. For example, the mobile phone is usually 0.35mV, and the CD is 1V, so the sound level is naturally different.

Q4: Why is there a loud current noise from the speaker?

A4: The loud current sound in the speaker has a lot to do with the power supply. The output ripple of many power adapters on the market is too large, which will interfere with the work of the power amplifier and cause loud current noise. Test it with a 12V battery. If the current noise is significantly reduced, it is a power supply problem. It is recommended to replace the power adapter with low output ripple or use a battery for power supply.

Q5: Why is there a loud buzzing sound in the speaker when one end of the AUX audio input line is connected to the product and the other end is not connected to the audio source?

A5: When the unshielded signal line is used, the audio line is equivalent to an antenna, which will receive electromagnetic waves in the air, and then send it into the amplifier for amplification. If you hate this sound, it is recommended that you replace it with a shielded line Signal cable or unplug the signal cable.

Q6: How to judge the noise floor of the machine?

A6: The noise floor has a lot to do with the quality of the power supply, the quality of the input audio, and the on-site use environment. The most standard way of judging is to connect to Bluetooth and play music with the smallest sound, with ears 0.5 meters away from the speakers, whether you can hear obvious low noise. If there is no obvious bottom noise, it is normal. If there is an obvious bottom noise, it is abnormal.

Q7: Why does the AUX interface make a "click" when plugging or unplugging the audio cable?

A7: Because the AUX input adopts the lossless input of signal relay switching, the sound of "click" is the sound of relay action. This is a normal sound, not a problem with the product.

Q8: Can the USB port provide external power supply?

A8: No, the USB interface can only be connected to a U disk or a computer USB interface.

1. Do not open the shell privately, as improper operation may damage the product.

2. Please use the switching power supply of a regular manufacturer, otherwise there is a risk of damage to the machine.

3. Do not use the machine in a high temperature and high humidity environment.

4. Before DIY, please make sure you have enough basic knowledge of electronics.