I hear/read that these headphones can sound more "smooth" and "transparent" when you give it more juice... not just to further increase volume but also refine some of V6/7506 headphone's rough edges such as its treble, "rebuild" the lost mids (when powered only with portable devices like iphones for example) and "tightening" loose ends and give "impact" with "confidence" in the bass area. The preceding is all what I mean by "With Authority" because this is what I remembered years ago how my V6/7506 sounded when powered by my aunt's Sony racks (what looks like a preamp and power amp from the1980s to learly 90s to me) when I visited her years ago.
The sony rack i mentioned did kinda "organize" the low end (according to my ears) and tighten loose ends. It felt like the the V6 driver was "well juiced" and I swear I think the driver was actually moving (can't find better words here... but it I can tell the V6 was "active" with the music from the pre-amp/power-amp sony racks)
I'd like to know the price range where I can experience this again if purchased new. I have a Costco-grade Pioneer home theater receiver with 1/4 headphone output... and they sound nowhere near like the racks mentioned above.