Review on Douk Audio Upgraded 50W+50W Wireless Bluetooth 4.0 HiFi Audio Receiver Digital Amplifier Board with Case and Heatsinks: Enhanced Audio Performance and Protection by Kev See

available The device works BUT at first I thought it was the 12V power supply I'm using, but then I connected a 12V DC battery as power supply (instead of the power supply) and the device still makes distinct noises. Floor. DIP switches actually make the noise level worse than the factory settings! The noise level is actually largely independent of the volume setting. A constant hiss + high frequency is added. This is audible, especially if you have young ears (that is, people under 70!). I think you get what you pay for.