Fosi Audio BOX X4 Phono Preamplifier Headphone Amplifier with 6J1 Vacuum Preamplifier for MM Turntables and Preamplifier for Record with and Treble

[Upgraded Version]: Upgraded from the Fosi Audio BOX X2. This is a next-generation phono preamplifier that delivers overwhelmingly high sound quality. 【6J1 Vacuum Tube MM Phono Preamplifier】: The BOX X4 phono preamplifier supports 3.5mm AUX and MM turntable inputs and converts phono signals to line-level signals. Low-noise integrated circuits and high-quality components eliminate low-frequency noise, resulting in clear sound quality. It is also equipped with a ground terminal to protect the turntable. 【Vacuum Tube Headphone Amplifier & Preamplifier】: The BOX X4 is equipped with 3.5mm AUX headphone and RCA outputs, making it more convenient than you might imagine. [Compatible Vacuum Tube Models]: 6K4/6J1/6J4/GE5654/6AK5/66*. You can DIY your stereo system by changing the vacuum tubes. Enjoy different sounds with different vacuum tubes. 【Package Contents】: Box x4 phono preamplifier, DC12V power supply, user manual. Comes with a 24-month warranty, guaranteeing reliable performance and customer satisfaction. *Note: The image shown is of a 5725W vacuum tube, but it has now been changed to a 6J1 vacuum tube. Input Interface: 3.5 mm turntable input, 3.5 mm aux input, 12 V DC input Output Interface: RCA output, 3.5 mm headphone output Output: Active (powered) speakers, amplifiers, headphones Applicable Headphone Type: 16Ω Output Voltage Level: 1 kHz and 650 mV SNR ≥ 70 dB THD ≤ 0.1 % Frequency Response: Standard RIAA