Been using the V10 for about an hour and I feel thankful to FINALLY have a phone where both the music sound quality AND the camera are among the best (if not the current best).
The sound quality is great. So far its very close (or only a small step below) my DAPs. Will post further details later.
As I hoped, it drives my Fostex mk3s to loud levels (at close to max volume). Not desktop amp levels of power but more than my DAPs (except for my iBasso R10).
It's EQ (which I almost never use) is the first portable one I've heard that doesn't immediately lower (or 'normalize') the volume when enabled. I expected to hear the usual drop in volume after turning it on (even before adjusting it). So far I can't hear any change in volume when simply turning the EQ (at flat levels) on and off. I tried the bass boost preset and it sounds/works more like what I'm used to hearing on external amp bass switches.
After switching the Hifi DAC on the phone detects each headphones' impedance. Initially, since headphones must be plugged in for the dac on/off to work, I didn't get enough volume even after switching the dac on. Just had to remove/reinsert the the headphones once and it adjusted the power and volume.
However, so far I noticed a potential problem that could make pairing difficult. The V10 will only output as much power as the level of impedance it detects from the headphone in use. And then the volume still behaves like standard android where it doesn't want you to go too high (to avoid hearing damage). For example, when I checked the dac settings with the mk3 plugged in, it said "High impedance device" and gives the most power. However, when I switched to my PM-3 or HD598 (thinking I'd have a TON of volume available), it says "Normal audio device" which reduces the power. So my mk3 with the V10 has a full, loud sound; best I've ever heard from a phone but I can't push my PM-3 to high enough levels because it only gives regular power levels instead of what's available to the mk3.
I had already planned to use the mk3 on the go so this isn't a huge issue for me (or probably anyone using low power iems) but, for anyone using "normal" impedance headphones, I'm worried they may not get the volume levels desired. They will get the better sound quality (with the dac on) but I almost wish the V10 had a manual gain setting instead. At the moment, as strange as it may sound, I'm thinking high impedance headphones (that don't require monolithic levels of power) or iems may be ideal for the V10. Anything with lower impedance, depending on the headphone, may require unusual levels of trial and error to find a good pairing.
I will post more info as I dig deeper into the V10 but if anyone sees something I've missed thus far please post it.
Otherwise, the V10 is already a keeper.
EDIT: Despite being relatively easy to drive, the V10 detects the Sony Z7 as "High impedance." Means it outputs it's maximum power leaving a ton of headroom available to the Z7. A very good pairing.
