Tube Phono Preamplifier: converts phono signals to Line Level Signals with Low-noise integrated circuits and high-quality components to remove low-frequency noise ensure clear sound quality; The Fosi Audio Box X2 delivers versatile phono preamplification with four selectable gain levels (OFF/39/42/45 dB) to optimize output while preserving sonic clarity. Dual input configuration accommodates both MM cartridges and line-level sources like CD players and DACs, with dedicated grounding protection for MM systems. Tube-based design allows customization through compatible replacements including JAN 5654W, 6K4, 6J1, and 6J4 variants, enabling fine-tuning of tonal characteristics. Includes 12V power supply and backed by comprehensive 24-month warranty with round-the-clock technical support.