I’m not an “audiophile”, but I do enjoy what I’ll call well-rendered audio (the focus is specifically on the quality of the sound reproduction, rather than the subjective enjoyability of the music). Here are some projects I’ve built to that end:
This is a summer project between my junior year of high school and freshman year at MIT. I went through a few prototypes, learned to etched double-sided circuit boards, and learned a lot about amplifier construction in the process. Because I didn’t want to take too many risks with what was at the time such an expensive project (actually quite cheap for a tube amplifier – the total was well under $300), I used Fred Nachbaur’s Minibloc SET design for the pre and power amplifier to ensure I built something that was guaranteed to sound good, but modified the power supply. 1 watt of output power is easily enough to fill my dorm room with music with the right speakers.