https://hifisonix.com/ The DIY site of the creator of Ovation amplifiers. Has very good projects with detailed build guides and a link to purchase boards. Also a number of detailed articles with those on grounding especially useful. http://www.markhennessy.co.uk/audio.htm Documents projects with extremely detailed guides. https://theslowdiyer.wordpress.com/ Documents his projects, and often makes the files available. https://emumannen.blogspot.com/ Very…