Product Name: 2.1 channel audio amplifier module

Product Model: ZK-MT21

Bluetooth Version: 5.0 (no shielding, 15 meters)

Input Sensitivity: 500mV

Audio Input: AUX + Bluetooth

Channel: 2.1

Chip Solution: Domestic power amplifier chip

Power Range: DC 12-24 V / 5A above (Do not connect to 24V battery pack)

Adapter Speaker: 20-100 W, 4-8 Ω

Output Power: Left and right channels <50W, Subwoofer <100W

Protection Mechanism: Anti reverse connection. Overheat. Overcurrent. Short circuit

Product Dimensions: 93mm*90mm*22mm

Package Weight : about 185g (packaging)

Tip: Only when the audio input is sufficient and the power supply voltage/current is sufficient, there will be sufficient output power. The higher the power supply voltage, the greater the output power, and the smaller the speaker impedance, the greater the output power. Please make sure that the power of the adapter power supply is greater than the actual working power of the amplifier!

Package includes:

1 x 2.1 channel audio amplifier module

(Requires simple assembly)

FAQ:

1. How to choose a power supply?

The power supply with the board is very important. The ripple of the selected power supply must be small. A power supply with a large ripple will cause the bottom noise of the power amplifier board to become larger and there will be current noise. The higher the voltage, the greater the current, and the more adequate the output power. The power supply is 12V1A and can be equipped with 34-inch speakers. If it is above 19V 5A, there is no problem with 8-10 inches, and the power supply must be highly regarded. If the voltage is too low, the amplified sound will easily cause sound distortion. If the current is too low, the speaker will pull down the voltage, which will result in abnormal operation or poor sound quality.

It is recommended to use a power supply of 18V19V24V with a current above 5A. If you only have 9V12V or 1A 2A power supply, it can be used but the power is low. When the volume is selected close to the maximum, it may be distorted and affect the sound quality.

2. How to choose a speaker?

Regarding speaker types: commonly used speakers are generally 4-8 ohms, which can be used. The left and right channel speakers need to be connected to full-range speakers or mid- to high-frequency speakers, and the power is between 20W-100W. The subwoofer speaker cannot be connected to an ordinary speaker, and a speaker with a subwoofer speaker must be connected with a power between 20-100. The dive frequency of the subwoofer speaker must be at least 50 Hz.

If your speaker has a low power, such as between 20W-50W, it can be used. You need a lower power supply voltage to prevent the speaker from burning after amplifying the sound. For example, choose a power supply below 15V.

If you are a 50W-100W speaker, don"t worry about the problem of speaker burnout. You can choose a 12-24V power supply. The higher the selected voltage, the greater the sound or power that can be output. The speaker power should not exceed 100W, otherwise it will affect the sound quality.

3. Introduction to audio input mode

This audio power amplifier module has two audio input methods: one is Bluetooth input, the other is AUX input, Bluetooth mode is preferred. Bluetooth can be connected in any mode. As long as the Bluetooth connection is successful, it is in Bluetooth mode, and the Bluetooth mode supports automatic connection back. When Bluetooth is not connected, AUX plug-in is in AUX mode. It should be note that when using AUX mode, you need to confirm that the Bluetooth connection of this module has been disconnected.

4. How to adjust the main volume?

The MAIN-VOLUME knob adjusts the main volume. Right-handed main volume increases, left-handed main volume decreases. The main volume affects the volume of the left and right channels and the subwoofer.

5. How to adjust the left and right channel high and low sounds?

The R&L CHANNEL-BASS knob controls the bass, right-turning bass enhancement, left-turning bass attenuation. When the knob is in the rightmost position, the bass is neither enhanced nor attenuated.

The R&L CHANNEL-TREBLE knob controls the treble, the right-handed treble is enhanced, and the left-handed treble is attenuated. When the knob is in the middle position, the high pitch is neither enhanced nor attenuated.

Note when adjusting the treble and bass: when the treble or bass is adjusted to the maximum by turning right, if the sound is distorted, the gain of the treble or bass adjustment is too large. You need to turn the treble or bass knob to the left to lower the gain or turn the right Turn the MAIN-VOLUME knob to the left to reduce the total volume.

6. How to adjust the subwoofer?

SUBWOOFER-VOLUME knob is used to control the volume of the subwoofer. Right-handed volume increases, and left-handed volume decreases.

The SUBWOOFER-FREQ knob controls the cutoff frequency of the subwoofer. The right-hand frequency increases, and the left-hand frequency decreases. The frequency adjustment range is 20HZ-200HZ.

7. The voice is small and okay. When the voice becomes louder, the voice becomes muddy?

The sound is distorted, please turn down the total volume or change to a higher voltage adapter power supply.

8. The sound is small, but when the sound becomes louder, the sound freezes?

If the input power is insufficient, the power supply itself is protected against intermittent power failure. Please replace it with a higher-power power supply; or if the power is too large, the power amplifier board will generate serious heat and thermal protection has occurred. Reduce power usage or enhance heat dissipation.

9. What factors are related to the sound quality?

The sound quality is not only related to the power amplifier module, but also related to the power supply, sound source, and the entire audio system. Basically, every aspect of the audio system will affect the sound quality, among which the main links are the audio transmission line, the audio power supply, the tone circuit, the power amplifier circuit, the speakers and the surrounding environment. The sound quality is the best only when the sound source, power supply, amplifier module and speakers are matched.