Mb Quart ZA1-320.4 320W 4-Channel Z-Line Series Class SQ A/B Amplifier RMS Power Rating: 4 ohms: 40 watts x 4 chan. / 2 ohms: 80 watts x 4 chan. / Bridged 4 ohms: 160 watts x 2 chan. Top mounted controls for simple setup & adjustment Fluid-FETS hand selected insulated MOSFETS Focused mass heat sink designs Q-Stasis preamp stage with wide input range