PC Part Picker for hi-fi stereos: https://buildhifi.com/

I've wanted this for a long time, so I finally started building it. I've had a lot fun!

- Graph-based signal flow: Products become nodes, connections are edges inferred from port compatibility (digital, analog, phono, speaker-level domains)

- Port profile system: Standardized port definitions (direction, domain, connector, channel mode) enable automatic connection inference

- Rule engine: Pluggable rules check completeness, power matching, phono stage requirements, DAC needs, and more