Zen Variations 8 — Nelson Pass / 2005

Thanks to a nice person on the Pass Labs Forum ( www.diyaudio.com ), I became aware that high current power JFET transistors are again available. You can check them out at www.lovoltech.com which offers a small variety of high current N-channel vertical JFETs in TO-251 and TO-252 packages. They don’t hold a lot of voltage 20-24 volts) or dissipate lot of power (69 watts, derated at 1.8 watts/degree), but they do deliver up to 100 amps peak. Clearly designed as switches, they nevertheless offer a linear operating region and are attractive for audio amplifier design. Small signal JFETs are routinely… More...

Zen Variations 1 — Nelson Pass / 2001

As an exploration into the potential performance of a very simple amplifier, the Zen amplifier has succeeded in creating notoriety and some controversy over the last 8 years. More importantly, it's novel and simple construction appears to have encouraged a large number of doit- yourselfers to take up a soldering iron and jump in. Having only a single gain device, the design's name is a pun on the Zen Koan, "What is the sound of one hand clapping?", but the point is quite serious. High quality sound can be obtained with simple and accessible circuits. Conversely, it is quite easy… More...