Features: This preamplifier needs to work with power amplifier or active speaker to get powerful HiFi music. Dual classical 6J2 tubes gives you warm and powerful sound, removable design for convenient replacement and upgrade. Supports BT, RCA and 3.5mm stereo audio input, you can play the music on your computer, CD player, smartphone, tablet or other audio players freely. The treble, bass and volume adjustment knobs allows you to modify the music sound according to your preferences. Compact size design, with all aluminum alloy shell, portable and durable. Gold-plated RCA input(L R) and output (L R) jacks ensure stable and lossless audio signal transmission.