HN replaces the www domain with old.reddit.com automatically. I can't access the page, but <a href="https://www.reddit.com/r/headphones/comments/1f2mavh/i_made_closedback_headphones_that_allow_for_extra/" rel="nofollow">https://www.reddit.com/r/headphones/comments/1f2mavh/i_made_...</a> works