This model optimizes the circuit, adds a power indicator, single power supply, AC and DC dual , and uses the enthusiast AD828 which is NE5532, and its performance and effect are further improved! The microphone board adopts the karaoke chip PT2399, chip technology, stable performance. Both the front and rear amplifiers of the microphone board use AD828 audiophile operational amplifier chips. Through the jumper cap setting, both electret microphones and dynamic microphones can be used. The power supply adopts a single power supply with a rectifier circuit, which can be used for both AC and DC. Product name: PT2399 Karaoke Reverb Board Working voltage: AC 6V-15V; DC 7-24V Processor speed: 2 Power: 4 Featured service: with AD828 pre-amplifier Colour: red Material: PCB+metal Size: 100x50mm Package Contents: 1 * PT2399 karaoke reverberation board 1 * connecting line Only the above package content, other products are not included. Note: Light 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.