Originally Posted by mattering
I heard the Vali had some hiss/noise but then again, i've never heard the vali and I've been spoilt by having a really dark/quiet background haha.
Originally Posted by cel4145
Hybrid tube amps like the Vali are a matter of personal tastes. A regular solid state amp aims towards transparency/accuracy. A hybrid tube amp adds a little tube sound (but not the same as a full tube amp) by adding what some people consider pleasurable distortion to the analog signal. It's not for everyone. I don't personally care for hybrid amps. Some people do.
One other benefit of tube amps is that people like is that you can change the tubes (aka "tube rolling") to tweak the sound to better fit the headphones you use with it and your personal listening tastes. Unfortunately, the Vali does not allow you to do that because the tube is soldered in.
Well what I found was teh Vali sounded substantially better than many of the "warm" solid states I've tried, I compared the Vali to my NFB10ES2 and it wasn't as much of a slaughter as I thought it would b, the Vali should nice dynamics, moderate tube sound [just enough imo] and for me it was well worth the money I spent. For the 250 Ohm DT 990 you won't hear the hiss, not sure about the HE 400, it might not be sensitive enough to pick up on it, but it might
still though the O2 is a good amp, but for the "brigt" ness some ppl complain about the HE 400 and DT 990, the Vali does a nice job smoothing that out, and what Cel said is right, solid states aim for a neutral sound, but your using two "colored" headphones, headphones with a touch extra bass and treble, there for the Vali which has a mild Mid centric sound, should balance it out, more so for the DT 990 than the HE 400, as the HE 400 has a very subdued upper mid response... of which only an EQ or Mods can fix