You Can DIY!: A High-Performance 60-Watt Class A Amplifier - Part 2 Power Supply and Measurements

The continuation of this 60-Watt Class A amplifier project, named the ax-Amplifier, this design uses Augmented Feedback Error Correction (AFEC) to achieve ultra-low distortion and improve key audio performance parameters without adding too much complexity and cost. The first part of this article described the amplifier design in detail. This second part details the power supply system and conclusion with measurements. This article was originally published in audioXpress, May 2024.

From the experienced hands of Andrew C. Russell, of Hifisonix fame, comes the ax-Amplifier, a Class A design that uses Augmented Feedback Error Correction (AFEC) to achieve ultra-low distortion and improve key audio performance parameters without adding too much complexity and cost. Published in two parts, the first article addresses the amplifier design in detail, with Part 2 detailing the power supply system and conclusion with measurements. This article was originally published in audioXpress, April 2024.

In the 2024 Glass Audio Special issue there’s Menno van der Veen’s TubeSociety TS-2022-OTL hybrid amplifier, and a Low-Feedback Triode Amplifier With Zero Output Impedance (ZOI) as DIY projects, designed by Tim Mellow and Peter Farrow. More great audio electronic articles by Rudolf Moers, Christopher Paul, and Dimitri Danyuk. Read about sustainable acoustical absorption, the Pure Acourate Sound Project, and The Neurochrome Story. And Andrew C. Russell concludes his High-Performance 60-Watt Class A Amplifier project.

Read the latest Earbuds and Hearables market update. sensiBel experts explain everything about the advantages of Microphone Array Beamforming with Optical MEMS Microphones. GRAS' researchers share their findings about Ear Canal Geometry for In-Ear Headphone Testing. Learn how Hearing and Audio affects our perception of music fidelity. Jan Didden interviews Menno van der Veen. Andrew Russell shares his High-Performance 60-Watt Class A Amplifier project, and Tom Perazella explains how to build a Comprehensive AC Power Controller.

For all our readers who started following the X-Altra Moving Coil/Moving Magnet RIAA EQ Preamplifier DIY project publish in the February 2021 edition of audioXpress, we have the final pieces. In this second article, Andrew C. Russell details the Moving Magnet EQ stage, system gain amplifier and filters, along with the system’s power supply unit. The article concludes with some measurements.

In this DIY project, Andrew C. Russell proposes the X-Altra, a highly refined Moving Coil/Moving Magnet RIAA EQ Preamplifier. This high-performance phono equalizer features an ultra-low noise LSK389B JFET from Linear Systems in the MM front end with switchable gain and resistive loading. This article was originally published in audioXpress, February 2021.

For this edition of audioXpress, start with our valuable Market Update on Audio Test and Measurement, followed by an interview and guided tour of QuantAsylum. From a practical perspective, Stuart Yaniger shares his experience with the latest version of Virtins Multi Instrument Measurement Software, Michael Steffes explains how to explore an interesting composite amplifier structure for great results, Mike Meechan continues his series on microphone preamplifier design, and Ethan Winer explains how to avoid too much wiring in large designs. Another great edition of audioXpress, now available to read in print and online.