Feature: 1. INPUT AND OUTPUT: The input of sound amp is balanced circuit design, can be single ended input, can also be balanced input, single ended input with a large two pole mono plug, balanced input with a large three pole dual channel plug, long distance transmission can be balanced 2. VOLTAGE AND SWITCH: 2CH sound amp working voltage between DC 5‑12V, independent power switch, there is a simple LED light, convenient for you to use 3. DUAL CHANNEL: Sound preamp support independent dual channel amplification, gain independent adjustment(0‑20DB), the two channels can be used individually, can also be used at the same time, do not affect each other 4. EASY TO USE: The output port is unbalanced single ended, both inputs and outputs is 6.35mm(1/4in) port. This amp is easy to connect and operate, simply plug in your devices and adjust the volume for amplification 5. APPLICABLE EQUIPMENT: Sound preamplifier is designed for having multiple sound sources and outputs, compatible with sound instruments, microphones, amps, preamplifiers Specification: Item Type: 2CH Sound Amp Material: Aluminum alloy Gain: 0-20db(independent adjustment) Operating Frequency: 20HZ-20KHZ Input Impedance: Single ended 10K, balanced 20K Output Impedance: 200Ω Operating Voltage: DC5V-12V Standby Power Consumption: 0.3W Operating Current: 5V 73MA, 12V 30MA Input Output: 6.35mm(1/4in). Package List: 1 x 2CH Sound Amp 1 x USB Power Cable Note: Use a 5V power supply from a power bank or excellent charger. Low quality charger may produce AC noise.