Description:  Kara OK board using the original PT2399 chip, responsible for the echo sound processing, the original PT2399 is a typical Kara 0K echo processing integrated circuits, in CD, VCD, DVD, TV audio 'Kara 0K machine a wide range of applications. Preamplifier with original dual amp NE5532 is responsible for audio signal amplification and effective processing.  Two-way microphone input + audio mixing technology.     Specification:  Name: karaoke reverberation board.  Output Load: 4-8ohm.  Working voltage: Dual AC12V.  Size: 100 * 57 * 17 mm.  Weight: 90g.     Note:  1. Using AC double 12V transformer only.  2. This board audio output part need connect amplifier board, can not directly connect to Audio.  3. Do not face the speaker to microphone.     Interface, Knob, Light Description:  1. Lin GND Rin: Represents the left channel / GND / right channel of the audio input signal.  2. Lout GND Rout: Represents the left channel / GND / right channel of the audio output signal.  3. MIC1 MIC2: used to connect the microphone, the microphone's connector plug directly.  4. Music volume knob: used to adjust the background music (accompaniment) sound size.  5. Microphone volume knob: used to adjust the microphone sound size.  6. Reverb Depth Knob: Used to adjust the playback frequency of the microphone.  7. Reverb Time knob: Used to adjust the microphone's playback time.     Package included:  1 x PT2399 Digital Microphone Amplifier Board