Tools https://www.random-science-tools.com/electronics/PI_attenuator.html eller https://audiokarma.org/forums/index.php?threads/diy-10db-attenuators.392186/

Endnu en WordPress-blog
TNT Italien site https://www.tnt-audio.com/int.html
Tone online mag https://www.tonepublications.com/review/
QUAD 405 Clone https://www.diyaudio.com/forums/solid-state/196210-quad-405-clone-13.html
Quad 405-2 ala LJM https://www.diyaudio.com/forums/attachments/vendor-s-bazaar/914201d1611353125-ljm-audio-ljm-quad405-2-schematic-png
QUAD 405 Zobel https://www.diyaudio.com/forums/solid-state/196210-quad-405-clone-5.html#post4097521
Rusian site with schematics https://translate.google.com/translate?hl=&sl=ru&tl=en&u=http%3A%2F%2Fwww.quad-405.ru%2Fdiy-china-clone-quad-405.html&sandbox=1
QUAD on EBAY https://www.ebay.de/itm/2pcs-QUAD405-125W-125W-power-amplifier-kit-dual-2-0-channel-for-HIFI-DIY/132357237977
My local server LMS
DK site with LMS hints https://www.cfuttrup.com/streamingaudio.html