Review on DAMGOO Bluetooth 50W+50W Stereo Audio Amplifier Board: Wireless DIY Speakers with Treble and Bass Control, BT 5.0, AUX Inputs - Easy Installation, Password Free by Brant Skogen

I have DAMGOO ZK-502T and ZK-1002 digital amplifier. Both work well with 16V laptop power supplies. Both ensure sufficient volume. I bought a class D for a TV and for a garage and got great results. I needed a replacement due to an apartment fire.** Mine broke after a few weeks. The BT ready signal kept beeping, interrupting music playback on the wired input. BT takes precedence and if it fails to connect you get stuck with repeated beeps. Revain chat support quickly arranged a warranty exchange with the return of the defective item. The exchanged item works perfectly. **The instructions for these speakers state what speaker size they support and that smaller speakers require less power. That is not right. The truth is that larger speakers tend to be more efficient. If you have very large and efficient speakers, you can probably drive them directly from your computer's sound card. i did this Your speakers will change everything; get good ones If you go to a thrift store, only buy well-known brands like Sony, Aiwa, Yamaha, KLH, Pioneer. Definitely not a smaller brand like Sharp or RCA. I have high quality Yamaha 8 ohm speakers. I will now focus on the differences between the two, which I believe are the most important. ZK-502Tpro: bass and treble controls! I like flexibility. Cons: Lame, glued-on heatsink, should probably be laid flat. Good value $20. Good, because mine is outside and exposed to the summer heat. Pro: Decent looking inductors but I can't hear the difference. Good value at $22. 4.5A) power supply for model ZK-502T. As expected, power consumption and output power are very low. Here are my results at 9V and (16V): Current consumption: Idle, off 40mA (40mA) Idle, on 80mA (100mA) Music plays loudest 100mA (110mA) Music plays loudest 150mA ( 200 mA) mA) Maximum power consumption 9V 1.35W, maximum possible output power 0.75W. The maximum usable power 16V 3.2W, the maximum possible output power 1.6W. The biggest difference between these two power supplies is that the audio is up to 3dB louder. The power regulator stays cold at 9V and starts heating at 16V. The main chip stays cold at 9V, but heat starts to build up at 16V and is slowly dissipated through the board and components. I used a thermal imager to test this and the highest temperature I've seen was a moderate 100 degrees Fahrenheit. Loud sound with low 9V power supply may cause crash and reboot. Therefore, only use a 9V or 12V power supply if you intend to listen at a moderate volume. With my 16V power supply, the current is sufficient for very loud music without interruption. More volume requires higher voltage, but this results in more heat. At 16V the temperature reaches 115 degrees Fahrenheit. Semiconductors can withstand much more heat, and the main TPA311 chip has thermal protection. Therefore, these measurements are for your information only. The attached sticker heatsink didn't get very hot - that's for show. However, the heat is also dissipated from the main chip through the circuit board. I scraped off the black adhesive and used thermal tape instead - with better results. I recommend you do this if you are using a 24V power supply! The reason I checked the current consumption was to confirm my suspicion: these amps are very efficient and draw little power. You could run it for a long time with a small 9V or 12V power supply, my audio source is a Sony Walkman MP3 player. Your source and/or a higher voltage power supply may give you more power output. But I don't think it will ever get anywhere near 25 watts and we should all be aware of that.- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Final edit: Additional tests with 12v battery and new setup. See photo of my weekend project: lithium-ion battery, solar power, convenient carrying handle. When the battery is disconnected and in direct sunlight, the panels feed it with medium volume. Connecting the battery extends battery life. Estimated lifetime 25 hours. (There is no time limit in direct sunlight.) Approximate power consumption: BT 40mA (OFF) Standby Aux 85mA Standby BT 75mA quiet 150mA medium volume 200mA loud volume 300mA Distortion starts at 350mA Full volume consumes an average of 500mA at 12.0 VDC. 5W output power with these 4 ohm speakers. Not bad! Good luck and have fun! - Chris