We use our exclusive KT90MC tubes to provide excellence in sound reproduction. The highest quality hand wound transformers by MIEG; utilizing Oxygen-Free Copper wire (OFC) around premium silicon steel laminations to provide exceptional audio frequency response for the highest fidelity. Hand assembled with point to point soldered high-grade electrolytic and coupling capacitors, resistors, potentiometers and rectifier. In addition to RCA inputs and output binding posts connected with silver Teflon jacketed wires. This amplifier is capable of installing KT90*, KT88*, KT120*, 6550* and EL34*. *All four power tube units must be of the same model type.