I spent another 6 hours last night listening to the Vali while playing games and it seems to sound worse the more I listen to it.
Now to my ears it sounds great with the modded Q701 and doesn't change a thing. It adds NOTHING and same with the two K400s I have.
To me it's not good really with the HD-650 and holds it back majorly compared to the Magni, Micro and O2. The HD-650 and DJ100 are the two headphones where the Vali adds in it's own colorations, which make them sound worse.
First tried docked Ipod Touch 2G to Vali and HD-650.
Sounded muffled/congested and closed in. Lack of detail and sound clarity.
I got the same results with my DJ100. Closed in congested sound and not clear at all. Not smooth and sloppy bass.
It's as if I can't even hear my Ipod Touch 2G. It's normally crystal clear sounding, but the Vali is crapping up it's good sound. 100% not the Ipod Touch's fault so don't even say it.
I switched to the Q701 and K400. PERFECT! Nothing added at all. What the...??
I then try my Denon 2190 CD player which has two Wolfson WM8740 DAC chips. Much better! Soundstage is a little bigger and I think this is the trick.
The problem is that the mids are so thick that it obscures detail and makes everything abnormally smooth. Sometimes it's nice, but mostly not. I would say with this setup I heard this "tubey" sound.
The DAC has some warmth too. Listened to this setup for 1 1/2 hours and liked it but sounded quite colored.
Vali and Modi is probably comparable to the Denon 2190 but less warmth in total.
Vali and Headroom Micro DAC sound the best easily. It uses the CS4398 chipset and seems pretty uncolored without any warmth at all. Vali adds in it's own flavor and I can't hear how good this DAC is.
Basically right now with everything I attach to the Vali it sounds like a Vali. I can't hear much difference, which is similar to the E9. It's the last amp i'd use to hear changes in my sources.
Loving it with the Q701 but with that it doesn't add anything and sounds dead neutral/transparent with that. It'd be interesting to try it with a DT-880 and see what happens there.
Right now it's not an amp i'd suggest for someone starting out or that wants a good all-rounder. IMO is more like a cheap toy to play with. I love it with the modded Q701 so that's good enough for me.
I'm listening to "Light Years" from Pearl Jam and it's really muffled and the bass is sort of farty sounding on the HD-650. Q701 is crystal clear on the Vali but the HD-650 sounds really veiled.
I think one of the problems is that the soundstage of the Vali (not from my sources) is kind of very compressed. This doesn't help the HD-650.
I imagine it will be a great match for anything that doesn't have a closed in soundstage that is too bassy or warm.
Now the question is why it seems so uncolored with the modded Q701 but much worse with the HD-650? With the Q701 it's about as good as my main setup and I feel as if I can HEAR my sources unlike with the HD-650/DJ100 and Vali.
EDIT: BTW just because I don't like the HD-650 with the Vali doesn't mean I hate the amp. I'll use it in my bedroom for just the Q701. I actually would like to see how the DT-880 does with the Vali. My bet is that it doesn't add anything to that (no extra warmth) just like with the Q701. I want to try a SR-60 on it too
I know it might be noisy.
EDIT2: I was just listening to a really trebly song and it actually sounded crystal clear with the Vali and 650. On songs where there is bass, the sound with the HD-650 can get more "hazy" and the sound (and clarity) takes a nose dive. I think the bass is just not very well controlled and a bit sloppy. Nothing too terrible. Maybe this is why I don't like it with the HD-650. Recordings with any kind of warmth feel as if they have a double whammy of warmth on the Vali.
You can hear the same things the Vali is doing to the HD-650 on the DJ100 w/M50 pads, but even more magnified. Just basically loose farty bass and a very closed in soundstage and lacking in sound clarity. The Vali actually isn't too noisy with the 38ohm DJ100. Sounds like a low mid emphasis coming form the Vali. HD-650 and DJ100 don't need this really. Strangely enough the 38ohm DJ100 sounds better from the Vali than the HD-650.