Asus Xonar STX with V5i vs V6 Vivid vs Woo Audio Fireflies (Gen2) I'm a PC gamer, a tinkerer and a modder. Plus I really value good quality audio. I bought my Asus Xonar STX back in 2012 when I built my first water-cooled gaming pc. I’ve been rolling opamps for a few years as a hobby but until recently nothing really stood out. A few months back I was reading and saw some impressive reviews on the Burson Audio opamps but I wasn't ready to part with the EMI shield just yet so I bought Burson V5i's for the I/V section. To tell the truth I wasn't overly impressed at first. Don't get me wrong- they sounded great; nice full sound, wide soundstage and the instrument placement/positional audio in games was nicely presented, but they weren’t life changing great which I had hoped. BTW- the new V5i's are different to some of the other V5i's I’ve seen in this forum- they don't have that little lip at the bottom anymore so they slot in real nice without fuss. Anyway, it wasn't until I swapped them out for my previous favourites (LME4970NA) that I could appreciate how good the V5i's actually were. I found the LME4970NA's were hollow and closed in comparison and the difference was so pronounced that I was soon looking forward to putting the V5i's back in. A few weeks later I got that itch again and started looking at the V5’s to see if they were a justifiable upgrade to the V5i’s. I saw the V6’s available for order. But the EMI shield!?! What do I do? So, I emailed Burson to see if they could shed some light on the importance on the shield. I asked, "Will removing the EMI/RFI shield (to fit the taller discrete amps) make any noticeable difference with interference?” I got a response, "Based on our experience the EMI shield on the STX card is purely cosmetic. We have done some lab test and we did not see any change to the noise performance in relation to the card with or without the shield." I ordered two V6 Vivid's. But they were taking a while to post and I got impatient (and a little crazy TBH). I bought a Woo Audio Fireflies (Gen2), a pair of Sennheiser HD600s and subscription to Tidal Masters. They arrived before the V6's. That combination was the incredible experience I was looking for. The Fireflies paired with the HD600s were so very warm, natural, clear, deep and smooth. Not a huge soundstage though which I hadn't expected. The treble is in no way fatiguing to listen to and even at high volumes. The sound is very flat and un-molested however it's not all gravy... Movies and games do sound good with the Fireflies but it seems to be missing a defined punchiness to the cracks and gunshots and explosions that i really enjoy. It's as if they were just too natural? Too smooth? It's hard to describe because there's nothing actually missing. Maybe I’m just used to the accentuated bass and treble in a lot of other speakers, headphones and amps. I like to be almost startled by those sounds in movies and games and that's definitely missing with the Fireflies. Eventually the Burson Audio V6 Vivid's arrived. I removed the EMI shield, strapped in the little red towers and plugged it all in. The sound... Mother of God the sound is phenomenal! So much punch, great soundstage and positional audio in games. Everything sounds brighter and more exciting with the V6's than with the Fireflies. The gunshots and explosions sound louder in contrast and give me that "WOW" factor I was looking for. There is no doubt in my mind they're noticeable improvement over the stock opamps and even the V5i's. I really love gaming with them; Escape from Tarkov, PUBG, Doom, Overwatch, Nier: Automata and Senua's Sacrifice all need to be heard through the V6 Vivids. It's really something else. Music is pretty great too but I honestly prefer the Fireflies experience for music and that’s mostly because the brightness of the V6's high end can be slightly fatiguing with the volume up high for long periods. But really, now I’m comparing the STX upgraded with Burson V6's to the likes of the $1600 Fireflies... and to me that makes them crazy good. PS. I got bored and cut a hole in the EMI shield for the V6 Vivids! Best of both worlds now.