My first "decent" headphones were Grado R2e (modded with Beautiful Audio cups and headband), after listening through the entire series of Grado headphones at the time (around 6 years ago). I went for Grado because of a whole lot of news stories about them. Then got some Dan Clark Ether2 (around 2K), and OMG the difference! The Grados are ear-piercingly shrill even on a tube headphone amp (Woo WA2SE with upgraded tubes) in comparison. I would strongly recommend to listen to something outside the Grado universe before buying anything. I also have some tinnitus, and obviously I noticed loads of differences.
