Interesantna saradnja Pass i Sony povodom 40 godina V-fet:
http://blog.sony.com/press/sony-demonstrates-pass-laboratories-40th-anniversary-commemorative-vfet-amplifier/
Sony’s VFET devices, also known as Static Induction Transistors (SIT), were smaller, less costly and much more efficient than conventional vacuum tube designs and were widely acknowledged for their “Triode-like” sound quality. Additionally, these transistors serve as extremely fast switching devices, which enabled Sony to introduce the first high-powered Class D audio amplifier in 1976.
This exclusive Pass Laboratories commemorative amplifier employs complementary matched pairs (2SK82 and 2SJ28) of Sony VFETs, which were in storage for nearly 40 years. The mono block amp operates in Class A mode, with a balanced circuit from input to output and no feedback required. The amplifier also includes a highly regulated stable power supply, which enables it to achieve 250 watts peak power into a 4 ohm load, with relatively low distortion (less than 2%).