(Of all the tube amps I've built the Darling is still my favorite for the sound, simplicity. The tubes were cheap enough to find — used in the radios in WWII bombers, made obsolete by solid-state and military inventory was dumped on the market. Maybe 1-Watt in power though? You might be surprised how listenable that is through full-range drivers + powered sub.)
Lot of projects/how-tos here: http://diyaudioprojects.com/Tubes/tubes.htm
Another DIY forum: https://www.diyaudio.com/community/forums/tubes-valves.5/
A "Darling" I built from scratch (I built over half a dozen in total): https://imgur.com/PBKOQMk
(Of all the tube amps I've built the Darling is still my favorite for the sound, simplicity. The tubes were cheap enough to find — used in the radios in WWII bombers, made obsolete by solid-state and military inventory was dumped on the market. Maybe 1-Watt in power though? You might be surprised how listenable that is through full-range drivers + powered sub.)
A Darling write-up that got me started https://www.nmr.mgh.harvard.edu/~reese/Projects/DoubleDarlin...