1. This line uses the DC boost line power supply DC12V can be boosted to more than 120V power supply; single DC12V1A (DC12V1A), the current is not limited, the voltage does not exceed 16V preamplifier; voltage amplification 5 times, amplification is a little big, hear the distortion can be reduced in moderation volume 2. Pre-stage working full-frequency output, full-frequency output does not exist there is a lack of any frequency, if you hear the high and low frequency which is less, please check your equipment preamp sensitivity: up to an effective 3V is not distorted! 3. Tube preamplifier is a class A amplification state (that is, the preamplifier is always amplified state), the signal line is recommended to use the line with shielding, otherwise it may produce interference with the sound and so on! 4. High-quality materials, experience enhanced audio fidelity, restore true sound. Stable product performance, upgraded for a variety of models of bile ducts. Preamplifier frequency response 5HZ-500KHZ, as long as your ears can hear the frequency through the preamplifier is the same as can be heard 5. The preamplifier has a toggle switch with three adjustable stages, which you can freely adjust according to your own preferences and audio settings. Wide range of applications, support for any low-level signal inputs Power supply:DC12-16V Current:greater than equal 1A Instructions for use: 1. Locator with switch:twist the knob clockwise to "tick" a light, then the volume is the minimum,continue to twist clockwise to increase the volume 2. tube filament:tube to be inserted in the end, boot to see the tube filament light red, note that the backlight is also red, to tube filament light machine to operate 3. Audio output input:near the power connector side is the output,the output should be connected to the amplifier or active speakers,the input to the audio source: such as cell phones,CDs,computers,TVs,MP3 a