This is a subset of textbooks in my library as well as various websites I find useful. In many cases, I refer to these references for the full derivations or explanations on a topic. Note that many textbooks are updated rather frequently and the newest edition is often incredibly expensive. I list the edition I use, which is often not the latest. Readers interested in buying these books will often be able to find considerable savings by picking up a used copy of an older edition.
The texts are listed alphabetically by author.
Blencowe: Merlin Blencowe: “Designing Power Supplies for Tube Amplifiers”. Wem Publishing, 2010. ISBN: 978-0-9561545-1-4.
Franco: Sergio Franco: “Design with Operational Amplifiers and Analog Integrated Circuits”, McGraw-Hill, 2002, ISBN: 0-07-232084-2.
Jones: Morgan Jones: “Valve Amplifiers”, 4th Edition, Newnes, 2012, ISBN: 978-0-08-096640-3.
Jung: Walt Jung (editor): “Op Amp Applications Handbook”, Newnes, 2005, ISBN: 0-7506-7844-5. Also available as a free download from Analog Devices, Inc.: Jung – Op Amp Applications Handbook.
Sedra/Smith: Adel S. Sedra, Kenneth C. Smith: “Microelectronic Circuits”, 5th Edition, Oxford, 2004. ISBN: 0-19-514251-9.
I generally prefer to read rather than watch, but I do occasionally come across reasonably well-produced and informative videos. I have linked to some of these below.
Ethan Winer: “The Null Tester”. An application of Baxandal’s summing circuit for testing ultra-low distortion and other non-idealities of audio components.
Ethan Winer: “AES Damn Lies Workshop”. In this video, Ethan Winer illustrates the important specifications of audio circuits. His description of the various distortion mechanisms and their impact on the perceived sound quality is excellent. He also points out what to look for in the various spec sheets and how to tell a good spec sheet from a useless one.