The 5881 is a very reliable tube that is widely used in many current production tube amplifiers. It has a warm tone with good 'bite.' This modern version is able to tolerate higher voltages than its 5881 / 6L6 cousins. The Sovtek 5881 delivers a warm, round tone that "sweetens" any vintage or modern guitar amp design. Built to rigid military standards, the 5881 will tolerate higher voltages than any other 6L6. In fact, they're frequently used as replacements for the old 7027 model in vintage Ampegs. Extremely consistent from piece to piece. The Sovtek 5881 has a heater voltage of 6.3 volts at 0.88 amperes. Maximum plate voltage is 250 volts while maximum plate current is 73 mA. The 5881 has a Transconductance rating of 6000 micromhos and a maximum output power of 5.8 watts.