The Audiophile's Project Sourcebook -

If you frequent the forums, you have seen this book referenced as "the Bible." But is it still relevant in an age of surface-mount components and Class-D hype? I dug into my dog-eared copy to find out. Don't let the word "Sourcebook" fool you. This isn't a coffee table picture book. It is a dense, 300+ page textbook for your ears.

He doesn't waste time telling you which capacitor brand "sounds warmer." He talks about Total Harmonic Distortion (THD), slew rate, and noise floors. If you are an objectivist who thinks expensive cables are snake oil, you will feel very at home here. the audiophile's project sourcebook

We’ve all been there. You’re staring at a pair of soldering lugs, a schematic that looks like abstract art, and a $500 price tag for a preamp you know you could build for $80. If you frequent the forums, you have seen

The gap between wanting to be a DIY audiophile and actually becoming one is often filled with confusion, smoke (literally), and regret. This isn't a coffee table picture book

You need to pair this book with the internet. Use it for the circuit topologies, the PCB layout guidance, and the safety rules. Then, go to Mouser or DigiKey with your phone to find modern equivalents for the transistors.