DIY PCB -Power supply for class-D (or AB) amps

Class AB Audio Power Amplifier Board Finished Dual-Channel 150-350W MOSFET L7

NEW REV-C! DIY PCB Tube PreAmp Power Supply, 6.3V/12.6V from 6.3AC, HV 50-400VDC

Dual Channel TDA7294 Audio HIFI Power Amplifier Board DIY Parts Kit PCB 200W New

HIFI Stereo Class A Power Amplifier Board Audio Amp Module High Quality DIY Kit

DIY PCB - ~5 watt linear "USB adapter"

DIY PCB Board OTL Tube Headphone Amp Aikido White Cathode Follower 6SN7 6BX7

DIY 100W Mono Digital Audio Power Amplifier Board TDA7294 HIFI Amp Module