Zen Variations 2 — Nelson Pass / 2002

Welcome back to the Zen Amp Variations. This is part 2 of many parts in which we explore some of the ways to make a very simple audio amplifier. In this and parts 3 and 4 we will embellish upon the original Zen amplifier circuit, improving the performance and creating the Penultimate Zen Amp. You may recall that the Zen Amp is a single MOSFET transistor operated in what is known as Common Source mode in which the input signal is fed to the Gate pin, the Source pin is grounded, and we take the output signal off the Drain.… More...

The Kleinhorn Part 2 — Nelson Pass / 2004

If you saw part one of this project (AudioXpress, January 2005), you know that the KleinHorn is a big toy, and you can imagine that it’s hard to resist playing with it further. When Chris and Matt built the horns last year, they made different driver chambers and replaceable front baffles, so that it would be easy to try different loudspeaker drivers. In this part we will first briefly explore some of the effects experienced with different amounts of absorbent stuffing in the horn as presented in Part 1. Then I will describe the effort to add scary deep bottom… More...