The Amazing FET Circlotron Construction, Continued — Michael Rothacher / 2008

A lot of would-be audio projects die on the vine, even when printed circuit boards and components are readily available. The planning, layout, and construction of the chassis metalwork are sometimes the barrier. Perhaps, this is why complete kits are often the first choice of beginners. To get you building, I’m including some additional information, a few instructions, pictures, and a parts list. Wherever possible, I’ve tried to select suppliers who have online stores so you can just “click” your way to a complete kit of parts. The Chassis To simplify construction of the FET Circlotron we’re going to go… More...

Zen I/V Converter — Nelson Pass / 2010

Thirteen years ago Pass Labs launched the D1, a dedicated Digital to Analog converter for high end audio. It was based on balanced PCM63 DAC chips with a current source output, which requires a separate current-to-voltage converter (known as an I/V) to turn its output into the voltage to drive other line level audio equipment. We didn't care much for the op-amp based solutions seen in the manufacturer's application notes and decided to approach this part of the circuit much differently. The PCM63, like other current output DACs, favors driving a very low impedance, preferably ground. You can easily create… More...