Basic parameters: Power amplifier board size: 200MM X 68MM X 30MM Class A and B output power: 4 ohms 300W 8 ohms 200W The default quiescent current is adjusted to 300MA Recommended input voltage: plus or minus 28V-45V DC input. Recommended transformer parameters: AC dual 24-35V dual AC output, power above 300W Recommended single-piece heat sink size: 250MM X 100MM X 55MM (product without heat sink) Reference L10 circuit design, using 1.6 mm double panel, 5-ring high-precision resistor, some small capacitors use Tianhe fever capacitors, new original tube (TT1943 and TT5200) 6 per channel (excellent control) Excitation tube For the (C5171 and A1930) audio pair tube, the circuit design is reasonable, the whole machine has no current sound, the sound quality is pure and thick, and the details are outstanding. Class A is warm and smooth, suitable for 4-12 inch boxes. This power amplifier board has one channel and one board, and sends 12Pcs insulation sheets. Colour: As Shown Material: Metal + Plastic Package Contents: 1 pair of sound 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.