You Can DIY! The DH-220C MOSFET Power Amplifier - Part 2 Construction and Testing Instructions

This reference DIY project details of an upgrade construction for the legendary Hafler DH-220 lateral MOSFET power amplifier, which can also be used to upgrade other Hafler models or even inspire new designs. The design is implemented on two PCBs, one as a drop-in replacement for the original Hafler circuit board and another board that consolidates all of the output stage wiring and components within the heatsink and under the main PCB. After the authors detailed the design and performance of the DH-220C upgrade amplifier, in this second part of the article, Bob Cordell and Rick Savas discuss the construction and testing. This article was originally published in audioXpress, August 2021.

This article offers the first serving of an amazing DIY project from amplifier experts Bob Cordell and Rick Savas with an upgrade for the legendary Hafler DH-220 lateral MOSFET power amplifier. The design is implemented on two PCBs, one as a drop-in replacement for the original Hafler circuit board and the other as a new board that consolidates all of the output stage wiring and components within the heatsink and under the main PCB. This article was originally published in audioXpress, July 2021

The August 2021 edition of audioXpress is now available in print and online. Read our Acoustical Solutions Round-Up 2021 and enjoy the DIY perspectives from Ethan Winer and Thomas Perazella on dealing with room measurements and treatments. David Logvin reviews Audio Precision's APx517B Acoustic Audio Analyzer, while Richard Honeycutt reflects on acoustic challenges for online and in-person meetings. And we conclude the DH-220C MOSFET Power Amplifier article by Bob Cordell and Rick Savas, and the VSCS Amplifier project in this edition.

One of the strongest issues ever in terms of audio electronics and market insights, audioXpress July 2021 is now available. This edition includes a complete overview of Audio Amplifier Technology and Design and its many application segments. Start with a review of the NAD Electronics M33 Masters streaming amplifier, followed by a great new upgrade design for the legendary Hafler DH-220 lateral MOSFET power amplifier, and then dive into a new hybrid voltage source and current source amplifier design for loudspeakers.