Fixing analog audio on the $2.58 HDMI-to-VGA adapter
Summary
The blog post documents a hands-on fix for noisy analog audio from a budget HDMI-to-VGA adapter used with a Nintendo Switch. The author performs detailed diagnostics (impedance measurements, oscilloscope captures) and identifies a high internal resistance in the DAC, then designs a low-pass filter to attenuate switching noise. The piece also covers PCB modding, DC-blocking considerations, channel swapping, and reflections on potential future second-order filter designs.