1. Adopting TINE5532 three piece design, it has primary gain, buffering, and tone processing functions. 2. Silent circuit design for power on/off, effectively avoiding impact noise during power on/off. 3. Supports DC9-29V wide voltage stable input, with positive and negative polarity reverse protection function. 4. Built in boost module, single power supply can be converted into dual power supply, with a large dynamic range. 5. Dual impedance output interface design, high impedance and low impedance meet the connection requirements of different power amplifier devices. Supply voltage: DC9-29V Static power consumption: about 1W Frequency response: 20HZ-20KHZ Amplification gain: 14db Tone adjustment range: ± 15db Input impedance: 50K High impedance output impedance: 10K, output amplitude: 0.7Vrms Low impedance output impedance: 600 Ω, output amplitude: 3.5Vrms Color: Material: PCB+Components Package Contents: 1 * Preamp Board 1 set * accessories (Accessory colors are random, specified colors are not accepted) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.