Mesa/Boogie Dual Rectifier 3-channel, 100-watt/50-watt Tube Amplifier Head Features at a Glance:MULTI-WATT 100W/50W (switchable by channel), Class A/B powerTube complement: 4 x 6L6, 5 x 12AX7, 2 x 5U4Bias Select switch (6L6/EL34)Fixed bias for consistent, maintenance free performance3 fully indepen..