What makes the Orpheus great is the synergy between the HE90 electrostatic headphones and the HEV90 tube-based amp. They were designed together, to work as one unit, and "voiced" appropriately, with (I believe) the goal to reproduce large-scale classical works as if you were in the concert hall. Mahler is glorious for sure, but try some opera and choral works. Try Orff, but not just Carmina Burana, listen to another piece in the trilogy, Catulli Carmina. I know that Senn made some additional HE90's without the amp, but forget that, they only sound good on an HEV90 (which had two HP jacks, so I think the extra HE90's were really intended to be second pairs for lucky Orpheus owners). The Stax 007 (and I think the 009) sound just as good with the right amp, maybe even better with a Blue Hawaii SE and vintage late-breakup Mullards. But any Stax will be fine, as will a SS amp that is voiced for Stax. Find them used on eBay. BTW, the word for what you seek is "euphonics". More than just "glorious transparency", more than wide frequency response, more that great imaging, more than transient speed -- that special something that just sounds like "you are there", to quote you. I have a very special SACD, live recording of "Sympathy for the Devil". You don't just hear Jagger spit, you feel it. "Every cop is a criminal" and the hair on the back of your neck stands up. I played it, 7 minutes +, for my brother-in-law (not in to classical) with all the lights off, only the tube glow (I monitored using my 007s, but gave him the Orpheus). He's a huge Stones fan. When it was done he was drenched in sweat, spent, like he had run a mile uphill. He never stops talking about it to this day. Good luck with your listening adventures.