2021 NEW MODEL: The updated version for BOX X2. Next-generation phono preamp for unrivaled sound quality. JAN 5654W Tube MM Phono Preamplifier: The BOX X4 phono preamp supports 3.5MM AUX and MM turntable input, converting phono signals to Line Level signals with low-noise integrated circuits and high-quality components to remove low-frequency noise ensure clear sound quality. Designed with a grounding post to protect your turntable. Tube Headphone Amplifier & Preamplifier: The BOX X4 is designed with a 3.5MM AUX headphone and RCA output, highly useful beyond imagination. Applicable Vacuum Tube Model: 5654W/6K4/6J1/6J4/GE5654/6AK5/66*In vacuum tubes, etc. You can replace the vacuum tubes to DIY your stereo system. Different tubes with different sounds. What You Get: BOX X4 phono preamp, DC 12V power supply, user manual, our worry-free 18-month warranty, and friendly customer service.