The item is a high-power but super mini 2-channel digital audio amplifier board, which can be very convenient to place in the gap of small plastic boxes or other devices. It can obtain maximum power output at a lower voltage, and features uilt-in standby electronic , high-gain buffer amplifier and short circuit protection. It is perfect for MP3, MP4 and Notebook PC. Features - Color: mainly red. - Material: durable PCB board and metal. : about 0.91 x 0.63 x 0.08 inch (2.3 x 1.6 x 0.2cm). - Positioning holes size: spacing 20mm; Aperture: about 2mm. - adn High Power 2-Channel 3W Super Mini Digital Audio Amplifier Circuit Board. - New efficient digital amplifier chip, and special internal output processing circuit. - Eliminating the conventional LC network. - Using EMI. - Power supply: .6V-5.5V. - Output power: 3W +3W (4 in Europe). - -to-noise ratio: 90dB. - Efficiency: more than 90%. - 2 channels 3W amplifier with PAM8403. - Output is CMOS BTL driver. - Cannot change any component parameters to protect IC. - The board can also powered by 5V USB power supply or 4 x 1.5V batteries. - It is perfect for MP3/MP4/notebook. Notes - Power positive and negative can not be reversed, the supply voltage can not 5.5V, these two violations would have led IC damage. - high-gain buffer can not be altered to to board any component parameters, does not meet the parameters will result in IC damage. - Input line try to use shielded line, you can play an anti- effect, clutter current sound. - Output for cmos tube BTL driver, the negative terminal of the left and right speakers can not be together, that the connecting to the speaker is completely independent, and does not allow ! Package list: 3 * High Power 2-Channel 3W Super Mini Digital Audio Amplifier Board Circuit Board (Red)