【Introduction】 ZK-502M AMP is a mini Bluetooth AMP smaller than a card, its peak output power can reach 50W+50W, wide voltage input: 5-24V, you can easily buy a matching DC power supply.【Friendly Design】this AMP protection board is printed with connection icons, allowing you to easily connect to each port without reading the manual.【It Has Many Functions In A Small Size】 This AMP has three input methods, their input sequence is USB mode→AUX mode→Bluetooth mode. You can directly connect to the computer through the USB interface without a driver, you can also connect to the playback device through the AUX 3.5mm interface, and finally, you can also connect to the mobile phone through the Bluetooth mode.【What Kind Of Speakers Are Connected To It? Active Speakers? Passive Speakers?】 There is no doubt that both can be connected. When you connect passive speakers, this AMP is a Bluetooth power amplifier; when you connect active speakers, this AMP is equivalent to a Bluetooth receiver. It should be noted that two types of speakers cannot be connected at the same time. You need to choose one type of speakers.Tip: adequate output power is required when the audio input is sufficient and the power supply voltage/current is sufficient, the relative power will be higher. Different impedance horns will have different output power.In the case of sufficient voltage and current, the larger the impedance horn, the smaller the relative sound power, please pay attention! Product Description Does it have a Bluetooth input mode? AUX input mode? It actually has a USB input mode? Yes, it has three input modes: 1. Bluetooth input mode: This AMP uses Bluetooth 5.0 version, which is compatible with other Bluetooth versions. 2. AUX input mode: The AUX mode of this AMP uses a 3.5mm interface, and audio signal cables with 3.5mm plugs can be used. The only thing to note is that when you buy an audio cable, try to buy an audio cable with good shielding effect. This is because the AUX mode uses an analog signal input. If the shielding effect of the signal cable is not good, it may cause noise. . Please be patient and listen to me introduce the last input mode: 3.USB sound card mode If you want to use it to play computer music, using USB sound card mode is the most recommended. Because the music played in USB mode is lossless, the sound is cleaner than in AUX mode. More importantly, you only need to connect via a USB data cable without driving. Please wait, and... If your USB flash drive is formatted in FAT32 and the capacity is less than 32GB, you can also copy the music directly to the USB flash drive, and the AMP will automatically play. The only drawback is that it cannot choose the previous and next song. What type of speakers can be connected to this AMP? There is no doubt that it can connect passive speakers and active speakers. When you connect passive speakers to it, it is equivalent to an AMP with Bluetooth function. When you connect an active speaker to it, it is equivalent to a Bluetooth receiver. Need to pay attention to the use, these two types of speakers cannot be used at the same time, you can only use one of them during playback. Packing: ZK-502M Power Amplifier Board * 1 Protective Shell * 1 Set DC Jack * 1 Screwdriver * 1 Knob * 1 Output Channel 2.0 2.1 2.0 2.0 2.0 Input Mode Bluetooth 5.0+3.5mm AUX+USB input Bluetooth 5.0+3.5mm AUX Bluetooth 5.0+3.5mm AUX Bluetooth 5.0+3.5mm AUX Bluetooth 5.0+3.5mm AUX MAX Power Output Per Channel 50W+50W 50W*2+100W 100W+100W 50W+50W 100W+100W Treble& Bass Control X Working Voltage DC 12-24V(Recommended Above 12V/5A) DC 9-24V(Recommended Above 12V/5A) DC 9-24V(Recommended Above 12V/5A) DC 9-24V(Recommended Above 12V/3A) DC 9-24V(Recommended Above 12V/5A) Does it include a power supply No No No No No