The SE300B supplies a power of 10W RMS and functions in pure class-A with single-ended mounting (the two tubes are in parallel) with an automatic bias. The two high voltages, driver and power, have vacuum-tube power supplies. The bandwidth (at –3dB) is from 20Hz to 20kHz, without any feedback. The driver stage, powered at 400V, is built around a double-triode 6SN7. The two elements of the tube are mounted in cascade. The output stage is powered at 320V, which allows the tubes to work in the best conditions.