The Zen Amplifier — Nelson Pass / 1993

I. "What is the sound of one transistor clapping?" There are two most essential principles to audio amplifier design. The first is simplicity. The second is linearity. Einstein said, "Everything should be made as simple as possible, but no simpler." Simplicity is a common element of the best and most subtle designs. It is preferred for purely aesthetic reasons, but also because fewer elements color the sound less, and lose less information. Many audiophiles, including myself, are willing to sacrifice other areas of performance to achieve the intimacy with the sound available through a simple circuit. An amplifier should be… More...

Current Source Amplifiers and Sensitive Full Range Drivers — Nelson Pass / 2004

Conventional wisdom holds that a pure voltage source amplifier is ideal for audio applications, and generally designers of loudspeakers work to that assumption. This belief has particularly been dominant since the development of high power solid-state amplifiers that began in the 1960’s. A small minority of audiophiles thinks otherwise, and these are often people using low wattage tube amplifiers with unusual looking speakers. Well, of course entertainment is full of fringe elements. A couple of years ago, Kent English and I were playing around with various ribbon tweeters, noting how the ribbons themselves seemed perfectly happy being driven by a… More...