Using Transistors to Emulate Vacuum Tube Sound Quality Based on Asymmetric Cycle Harmonic Injection Method

It is well-known that vacuum tube amplifiers and solid-state amplifiers sound different. An important factor accounting for the difference is output harmonic contents. This paper describes a novel analog method to change the harmonic contents of a signal. Based on this method, a transistor amplifier with controllable output harmonics has been built. Performance has been evaluated by both objective measurements and subjective listening.