Resource
Pass DIY
DIY archive collecting Nelson Pass and Mike Rothacher articles, project files and related resources. Its library spans Class A amplifiers, preamplifiers, crossovers and speaker work, with downloadable designs such as Amp Camp Amp explaining both the circuit and the practical constraints of building it.
About this resource
Pass DIY is an article and project archive rather than a conventional finished-equipment catalogue. Its welcome page describes preserving Nelson and Mike’s work, including files, classic schematics, historical material and a DIY crossover simulator. The navigation separates articles by Nelson Pass and Mike Rothacher from other resources and applications, giving builders several routes through the collection. [1] [2] [3] [4]
The Nelson Pass index includes Zen variations, B1 buffer preamplification, F5 Turbo, Sony VFET projects, power-supply articles and crossover designs. That breadth shows an emphasis on understanding and constructing electronics, not just selecting a kit by name. The downloadable Amp Camp Amp number one article is a particularly concrete example: it explains a discrete four-transistor, single-ended Class A amplifier intended to lower the barrier to getting started. [2] [5]
That article also treats safety as a design constraint, using a commercially available isolated switching supply rather than asking inexperienced participants to assemble a mains-connected supply. It walks through the gain device, constant-current source and additional circuit elements, connecting the schematic with how the amplifier operates. Historical designs and event references should be read in their original context; an archive entry is not confirmation that its exact parts or a matching commercial kit remain available today. [5]
Verification sources
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