Product selling point:
1: Potentiometer to adjust the volume, with switch, easy to control the volume, very suitable for DIY speakers
2: Copper DC connector is used, which can withstand large current and does not generate heat
3: left and right double channel (stereo)
4: small size
5: Easy to use


Parameters:
Product Name: Mini Version 2X50W Bluetooth Digital Power Amplifier Board
Product Model: ZK-502L
Adaptive power supply voltage: 5~24V (9V/12V/15V18V/24V and other adapters are optional, and high voltage is recommended for high power)
Compatible speakers: 30W~200W, 4Ω, 8Ω
Number of channels: left and right double channels (stereo)
Bluetooth version: 5.0
Bluetooth transmission distance: 15 meters (no occlusion)
Protection mechanism: self-recovery overheat protection, self-recovery short circuit protection


Tips:
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 higher the relative power, and the speakers with different impedances will have different output power. When the voltage and current are sufficient, the greater the ohm of the speaker, the smaller the relative sound power, please pay attention!


Voltage:
12V ---- 8 ohm speaker/12W (left channel) + 12W (right channel), 4 ohm speaker/20W+20W
15V----- 8Ω/18 + 18W, 4Ω/greater than 30 + 30W
19V ----- 8 ohms/32 + 32W, 4 ohms/greater than 45 + 45W
24V ----- 8Ω/38 + 38W, 4Ω/more than 50 + 50W


Answers to questions:

1. How to choose a power supply?
A: The power supply of the board is very important. The higher the voltage, the greater the current, and the greater the output power. If you only have 12V 1A, you can use 3-4 inch speakers. If you are above 19V 5A, there is no problem with 8-10 inches, and the power supply must be highly valued. If the voltage is too low, the sound will be easily distorted after the sound is amplified. If the current is too small, the speaker will not work, and the voltage will be lowered, and the work will not work properly or the sound quality will deteriorate.

It is recommended to use 18V19V24V power supply with a current of more than 3A. If you only have a 9V12V or 1A 2A power supply, it can also be used but the power is low. Note that the volume may be distorted and affect the sound quality.

2. How to choose speakers?
A: Commonly used speakers are generally 8 ohms, and the effect is the same regardless of positive and negative polarity. 4 ohm speakers can also be used. If your speaker power is low, it may be between 10W-30W, and the power supply voltage should be lower to prevent the speaker from being burned after amplifying the sound. For example, choose a power supply below 15V. If you have a 50W-200w speaker, you don't have to worry about burning the speaker. You can choose a 12-24V power supply. The higher the voltage you choose, the greater the output sound or power.

3. How to connect Bluetooth?
A: Power on the power amplifier board, connect the speaker, turn the audio knob to turn on the indicator light, turn on the mobile phone settings--Bluetooth--search for "BT-WUZHI", then click to connect, there will be a ding-dong prompt after the connection is successful, then When it is in Bluetooth mode, just play music, and it will automatically connect back to the phone next time it is powered on.

4. It's okay if the sound is small, but after the sound becomes louder, the sound becomes muddy?
A: The sound is distorted, please change the power adapter with a higher voltage level.

5. It's okay if the sound is small, but when the sound becomes louder, the sound freezes?
A: The power of the input power supply is insufficient, and the power supply itself is intermittently powered off for protection, please replace it with a higher power supply; or the power is too large, the power amplifier board heats up severely, and thermal protection occurs, reduce power usage or strengthen heat dissipation.