A40 Class A Audio Power Amplifier Boards (pair of PCBs, no parts)

Class A audio power amplifier. Designed by Nelson Pass and enjoys steady following despite being around for 40 years. 40 Watts per channel. Low part count, all through hole, easy to assemble. One board per channel; two boards are required for a stereo amplifier. The board closely follows the published design, plus it allows using the current source JFET (Q11 on the schematic) with any pinout, making part substitution easier. Bare boards only. Parts are not included and need to be obtained separately. Assembly is required. The output stage (4x power Darlinton transistors and 4x 0.68ohm emitter resistors) needs to be assembled off board. References: The original article by Nelson Pass A discussion of possible part substitution for the A40 Shared project on Mouser