1. The Audio signal input end can be connectted to the computer, CD, phone and other player for lossless audio . 2. The output end can be connectted to the digital amplifiers, active multimedia audio devices 3. It's with treble and bass adjustment function 4. This is the preamp, not power amplifier. It needs to be connected to the amplifier or active audio devices. 5. Gold-plated for input and output terminals 6. 6J1 valve tube 7. No background noise Specifications: 1. Audio input: RCA input * 1 group 2. Audio output: RCA output * 1 group 3. Power DC input: 12V input 4. Aluminum shell, CNC processing 5. Laser carving prints 6. Color: Silver