This is one of the reasons why I love the retro game community so much because long after the lifespan of a console is over people are still creating really amazing hardware to keep systems going.
https://zzblogs.wixsite.com/home/single-post/pnpgc2
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Yeah, you can get stereo and hdmi for your NES these days if you're comfortable with hardware modding. It's amazing how people push the old tech.