Check the listing for details. 2PC ZK-502MT 50W*2 Bluetooth 5.2 Audio Amplifier Board Module Tone Adjustable. Condition: New. Listed at 21.86 USD. Product Features:Independent high and bass adjustment, dual channel stereo outputBluetooth 5.0 input, unobstructed 15 metersWith protection mechanism, overheat, overcurrent, short circuit protection function50W * 2 with tone Bluetooth audio amplifier module, small distortion, wide range of adjustmentWide range of application, suitable for cell phones, tablets, laptops, etc. Product parameters:Product Model:ZK-502MTBluetooth version: 5.0 (unobstructed, 15 meters)Signal to noise ratio: >90 dBInput mode: AUX + BluetoothPower amplifier chip: domestic power amplifier chipNumber of channels: left and right dual channel (stereo)Adaptable speakers: 15 ~ 100W, 4 ~ 8ΩAdaptable power supply: DC 9 ~ 24V/3A or more (can not be connected to 24V battery pack)Protection mechanism: overheating, overcurrent, short-circuit protectionPower supply voltage:12V -----8Ω/12W+12W, 4Ω/20W+20W15V -----8Ω/18W+18W, 4Ω/30W+30W19V-----8Ω/30W+30W, 4Ω/40W+40W24V----8Ω/40W+40W,4Ω/50W+50WProduct size:89mm*60mm*21mmTips.1. In the case of sufficient audio input, the power supply voltage/current is sufficient to have sufficient output power!2. The higher the power supply voltage, the higher the output power, the smaller the speaker impedance, the higher the output power!3. Please ensure that the power of the adaptable power supply is greater than the actual working power of the amplifier! Product list:2* Amplifier module2* Shell2* Accessories Questions answered.1. How to choose the power supply?The board with the power supply is very critical. The higher the voltage, the higher the current, the more output power, if you only 12V1A, so you can take 3-4 inch speakers. If you are more than 19V 5A, with 8-10 inch no problem, the power supply must pay great attention. If the voltage is too low sound amplification is easy to cause sound distortion, if the current is too small to bring up the speaker will pull the voltage down, not working properly or poor sound quality.Recommend the use of 18V19V24V power supply, the current of more than 5A. If you only have 9V12V or 1A2A power supply, you can also use but the power is small, pay attention to the use of the volume to the maximum may be distorted, affecting the sound quality.2. How to choose the speaker?Commonly used speakers are generally 4-8 ohms, can not distinguish between positive and negative polarity, the effect is the same. If your speaker power is small, may be between 20-50W can also be used, the supply voltage is small to prevent loud burn speaker, such as the choice of 15V power supply below. If you are 100W -200W speakers, do not worry about the problem of speaker burn, you can choose 12-24V power supply, the higher the selected voltage, then the greater the output sound or power. Speaker power is not easy to exceed 200W, otherwise it will affect the sound quality.3. How to adjust the high and low tones?The BASS potentiometer in the middle is to control the bass, right rotation bass enhancement, left rotation bass attenuation. When the potentiometer is in the middle position, the bass is not enhanced nor attenuated;The left TREBLE potentiometer is to control the treble, right-turn treble enhancement, left-turn treble attenuation. When the potentiometer is in the middle position, the treble is not enhanced nor attenuatedHigh-bass adjustment need to pay attention to: when the treble or bass right rotation adjustment to close to the maximum if the sound distortion, that the treble or bass adjustment gain is too large, you need to treble or bass potentiometer left rotation, the gain down or the right VOLUME volume potentiometer left rotation, so that the total volume is reduced.4. What factors are related to the quality of sound?The sound quality is not only related to the amplifier module, but also with the sound source and the entire audio system. Basically, each link of the audio system will affect the sound quality, the main links are audio transmission lines, audio power, tone circuits, amplifier circuits, speakers and the surrounding environment. Only when the audio source, amplifier module and speakers match, the sound quality is the best.5. Small sound is fine, the sound becomes larger, the phenomenon of muddy sound?Sound distortion, please change the voltage level higher adapter power supply.6. small sound is fine, the sound becomes louder, the phenomenon of sound stuttering?Input power supply power shortage, the power supply itself intermittent power failure protection, please replace the power supply with a higher power; or too much power, the amplifier board heat serious, thermal protection, reduce the power to use or strengthen the heat dissipation. On Sep 29, 2024 at 04:13:46 PDT, seller added the following information: