So I took some time to do some listening and comparisons between the nfb-10es2’s amp section, the Vali, and the project sunrise (full music 12U7 tube) fed by the nfb-10es2’s dac section and then fed to the hd800s and hd600s.
I think I’m lucky and got a pretty good unit, as the only way to get the amp to ring is by plugging in the headphones or hitting a metal piece (like my xlr adapter) onto the chassis. There is a little bit of floor noise with the hd600 and hd800 while no music is playing, but is inaudible once something starts playing. The Vali was too noisy for my UERMs, so I suspect it won’t work well with other CIEMs either.The build quality is great, but I wish that the power LED was a bit dimmer... for now, I just put some electric tape over the LED opening.
Moving onto the Vali's sound...
Vali – This is an amazing intro to tubes at just $119. Overall the amp is fairly neutral and does not add much coloration to the sound. As for soundstaging, the amp has good width but is lacking in depth. As a result, the Vali makes your music sound more upfront. The Vali is very dynamic sounding and does not smear quieter sounds when louder sounds are being played at the same time. Like mentioned by purrin, the Vali adds some “wetness” to the sound, which can be quite pleasant, especially with brighter headphones. I also notice some slight warmth, likely due to the slower decay. As for the treble, the Vali does not roll off at all but does seem to make the treble slightly smooth.
Vali w/ hd800 (Anax 2.0) – Fantastic synergy. The Vali is completely cable of driving the hd800s both sound quality wise and volume wise. The wetness that the Vali adds makes the hd800 very musical and euphonic to listen to. The bass is impactful, and the mids have a nice thickness to them that makes vocals more seductive to listen to. The upfrontness of the Vali works well to the hd800 imo, which I felt was kind of distant sometimes. The width of the hd800 is slightly hindered by the Vali but it is a minor con. $119 amp with a $1500 headphone? Totally works.
Vali w/ hd600 – Ehhh… Not that great of a pairing. The characteristics of the Vali does not mix well with the hd600 imo. The mids of the hd600 are already upfront and have some thickness to it already, and I feel that the Vali adds a bit too much to it. The hd600s are not known for their soundstage and the Vali hinders it way too much. Everything sounds clustered, congested, and in your face.
12/17/2013 edit: Well, I spent a little more time with the vali and hd600 combo today and it actually doesn't seem to be as bad as I thought it was initially when i wrote this. I think it's mainly because I'm just really used to how the hd800s sound, and the hd600s feel very closed in and upfront in comparison. It's a fine combo.
Vali vs the NFB-10es2’s amp section (w/ warm jumpers in place) – Both the hd800s and hd600s used the balanced output of the 10es2 for this test. The hd800 is excellent with the nfb-10es2 but I like the tonality of the Vali much more. The main thing that the 10es2 wins over the Vali is in soundstaging. It is a little bit wider, and certainly has more depth to it. Overall the 10es2 just sounds… cleaner, which works well for some genres. The hd600, when balanced, sound much better with the 10es2 compared to the Vali. The strong points of the 10es2 helps balance out the weak points of the hd600s. The hd600s sound much more open with the 10es2.
Vali vs Project Sunrise (Full Music 12AU7) – No contest here, the Vali wins over the Sunrise in pretty much every way, especially at less than ½ the price of the Sunrise. Well okay, the Sunrise is quieter (no audible hiss), and probably works with more headphones than the Vali. But to my ears, the Vali sounds better than the Sunrise with the hd800s.
Vali & Dacs – I’m going to reiterate what others have said: you NEED a good dac to get the most out of this amp. The NFB10-es2 is a good pairing and feels like it brings out most if not all of the Vali (I don’t have any $1000+ dacs so I dunno). The DX50 did okay… but wasn’t quite up there with the 10es2. The hifimediy dac (non async) was complete **** with the Vali. It made the vali + hd800 sound thin and somewhat closed in.
Props to Schiit for making this fantastic amp. While it works well with the hd800s, it doesn’t seem to pair well with the hd600s imo. I can’t speak for other headphones, but it seems like the vali would work well for brighter headphones. There are limitations to the Vali like microphonics, high output impedance, soundstage depth, headphone matching. But if you have a pair of headphones that synergizes well with the Vali, it is a champ for just $119. But I really have to reiterate, you have to get a good dac to get the most out of the Vali.
IMO, YMMV, caveat emptor, etc etc.
Added 12/16/2013: Comparison between Vali and Little Dot MK III
I did all of my comparing with the hd800 (anax 2.0 modded) while my friend used his hd600s (old black drivers). The little dot was equipped with the Sylvania Gold Brand 5654 tubes. Overall our impressions between the two were very similar; with me noticing more differences than he did.
Soundstage - It felt like the little dot had a little bit more depth to it than the vali, however, the vali was a little bit wider. The Vali's soundstage was more coherent, with the instruments and vocals filling the soundstage more appropiately.
Bass - The Vali was punchier, and also brought out more subbass than the little dot.
Mids - The vali had more wetness to it than the little dot, despite it being a a hybrid compared to a OTL. The mids on the vali were more enjoyable than on the little dot.
Treble - The vali was slightly brighter than the little dot and stood out more, due to the lively nature of the vali. It was also more detailed as well.
Other comments - The vali was more dynamic and lively sounding whereas the little dot is the typical OTL tube amp with its warm sounding and smooth nature. However due to the smoothness, the amp was lacking dynamics. The bass and cymbals hit harder on the vali, which I felt was more true to the track's nature The Vali was more revealing and transparent than the little dot and brings out more of your dac than the little dot does. It will scale better with your dacs than the little dot as well.
Edited by thegunner100 - 12/17/13 at 12:05pm