First Watt, the audio firm set up 10 years ago by Nelson Pass to build limited runs of some of his best known designs, has just released the J2 stereo amp. This update on the F2 features 25 watts of class A power per side, but in place of MOS-FET output devices uses high-power J-FETs from manufacturer SemiSouth Corporation of Missouri. Originally designed for very fast high power switching in solar power and electric car applications, the J-FETs apparently also have a very low distortion characteristic which makes them eminently suitable for use in linear amplifiers.  Pass claims that, compared to similar MOS-FETs used in the same circuit topology, they can produce 10 to 20dB less distortion.