Warning! I come to give my opinion on this "preamp". To begin, I received this one damaged, with scratches on the sheet, one of the connectors rca moves in the void. The RCA connectors are also almost rusty. Then, when I plugged in and turned on the device, what a horror! The gain (+ 50dB) is so strong that it can break your speakers. Can not turn the volume knob one step. Add to that a huge background noise, hum, hiss, bzzzz that can be heard several meters away. In addition, one of the channels does not seem to work properly. If you touch the device, you take an electric shock! When you open the device, you understand why it does not work. It lacks a negative cable, it lacks a connection to the ground The welds do not fit on the pcb, the wires hang in the void and are held with a little glue. There are also two chemical capacitors that are marked and distorted. This material is totally unusable and dangerous. It's a shame!
preamplifier arrived not working. So it means that they are not tested before shipping. Aliexspress repaid me even if I lost ten euros. I was very disappointed 30 days to get it and it didn't even turn on.