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