Review on 🔊 Fosi Audio DA-2120A Bluetooth Amplifier Stereo Hi-Fi 2.1 Channel Wireless Stream aptX, 24Bit/192kHz Class D Compact Mini Power Amp with Integrated USB DAC Coaxial Optical, Subwoofer Support & Remote Control by Sharon Payne

The first device generated unwanted noise for the active subwoofer. I've tested with multiple cables and even multiple subwoofers. The second device doesn't make any unwanted noise and sounds like it costs a lot more than this one. I use my old home theater gear for speakers and they sound as good as a $600 Denon AVR. I'm connected via a Macbook Pro, but you can get the same results on a PC. The reason for such high sound quality is that you can connect via USB (the blue cable in the picture) and send the sound in a purely digital format (aka SPDIF). This allows you to use a higher quality DAC on Fosi, free from the noise of your computer. Signal loss and interference are not possible over short distances for digital audio. Alternatively, if you're using a console or similar, there's a coaxial or optical input that will do the same. Do not use "Aux" for maximum sound quality as it may cause signal loss and noise. There is also Bluetooth, which transmits sound without loss, but the technology itself leads to a loss of quality due to the low transmission speed. If you are using SPDIF, you cannot change the volume in the software using the volume controls on your Mac/PC. /whatever or keyboard. You have to use the giant volume knob on the front of the Fosi or the remote control which works well and has many steps to allow you to listen at different volumes. From the device I am connected with cables that I made myself from a banana. Plugs bought here from Revain and a cheap RCA cable to send audio to the sub. If possible, these cables should not be located next to power cables. The downside is that the device is so small you can see how packed everything is. These power cords shouldn't be touching and gravity will work against you when stacked like this, instead they should be 4 wide. Also, the power cord is a bit too close to the left speaker output, although to be honest I don't hear any distortion or hiss at any volume on this unit. I don't have a Bluetooth antenna connected and I don't intend to use this feature.