AB400 dual channel professional stage amplifier board circuit design is mature and stable, the use of double differential input and increase the input signal processing, the push stage with a pair of 1930/5171 and 5200/1943 to do compound push, and then 16 tubes to do the power output stage, the output power up to 400W+400W.Great power, strong low frequency, rich details, the circuit adopts DC feedback design, good analytical power, good bass deep elasticity, stable work under high power, retracting and retracting freely.The board design has a perfect protection circuit, including switch delay protection, to prevent impact sound.Midpoint voltage protection, overcurrent protection, high temperature protection, and cooling fan interface.Selected TTA1943/TTC5200 audio tube, carefully matched after assembly. Model:AB400Output channel: 2.0 channelMagnification: 25xPower amplifier tube: TTA1943 x 8, TTC5200 x 8Frequency response range:20-20KHzMain voltage: DC dual 50V-110V, you need to add a rectifier board yourselfOutput power: 400W+400W/4, 200W+200W/8Total harmonic distortion: 0.01%Protection mechanism: overheating protection, overcurrent protection, midpoint voltage protection, power-on delay protectionSize: 220 x 84 x 100mmMaterial: plastic+metalColor as shown Package Contents:1 x Amplifier board 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.