This small amp board performs very well with a 19 volt, 4 amp notebook power supply, much depends on the power supply! Incredible, how much power comes out of this tiny board. Cost performance ratio is of the scale! Great product for a small price. Only downside of most of these boards is the limited high frequency reproduction, low's and mid's are clean, high's are a little on the harsh side, but as background and media amp, great! Not for high end audio but given the price, unbeatable!