Feature: 1. Phono Preamplifier: Uses low noise integrated circuits and premium components to convert phonograph signals into line level signals, reducing low frequency noise and ensuring clear sound quality. Design a grounding pole to protect your turntable. 2. 3 Gain Modes: 39, 42, and 45 dB. The adjustable gain level provides you with simple control and excellent compatibility. Entry level high end analog sound and great circuits. 3. Simple Circuit Layout: Simple wiring ensures clear HiFi sound quality and low noise, using 2pcs 6J2 vacuum tube, making the sound warm, dynamic, and sweet, bringing great sound quality. Excellent listening experience. 4. Compact and Exquisite: Aluminum alloy casing with better shielding performance, gold plated terminals for stable transmission, perfect for sound sources such as MM player. You can replace the vacuum tube to DIY your stereo system. 5. Wide Compatibility: Equipped with MM signal input and 3.5mm AUX input for priority, it can be used as the front stage of MM phonograph and electronic tube, compatible with various audio devices, such as MM phonograph, mobile phone, TV, MP3 player, CD player, DAC, computer, etc., to meet different needs. Specification: Item Type: Vacuum Tube Amplifier Material: Aluminum Alloy Model: BOX P4 Audio Input: MM player or 3.5mm AUX Audio Output: Stereo RCA Output Level: 600mV at 3mV 1KHz. Signal to Noise Ratio: ≥ 98dB Frequency Response: In accordance with RIAA standards. Total Harmonic Distortion: 0.1% Working Voltage: DC 12V Power Adapter: US plug AC 100-240V 50/60HZ. . Package List: 1 x Vacuum Tube Amplifier1 x Power Adapter2 x Vacuum Tube1 x Audio Cable1 x User Manual Note: 1. Do not open the shell by yourself, improper operation may cause electric shock. 2. Please use a standard switch power supply, as there may be damage to the machine. 3. When plugging and unplugging input and output cables, please cut off the power before operating, as the impact sound may damage your audio system. 4. Do not operate the machine in a high temperature and humidity environment. 5. Do not replace mismatched electronic tube models as they may burn out your electronic tube and machine.