Originally Posted by kstuart
Okay, I now have well over 100 hours of burn-in, here are the first reactions:
* The burn-in clears up and elevates the treble and upper mids. At unboxing, the Vali seemed dull on the high end, and now it is bright (but not overly so).
* I like the Vali the most with the.... Mad Dogs. The Mad Dogs seem to have just enough sensitivity and the Vali just enough power for the combination to work well. Or it could be due to some other electrical aspect. The Vali has a shallow soundstage, and this is not a problem with the Mad Dog because it also has a shallow soundstage.
* I don't like the Vali with the HE-400. It sounds congested - there is a hint of distortion on quick transients. I also did not like the HE-400 with the Magni and it may be that the output stage of both is in common and is not a good match for the HE-400. I find that the HE-400 is like the other HiFiMen, in that it sounds much better on a vintage power amp (or the Emotiva which I have not heard).
* The Alpha Dog does not work as well with the Vali as the Mad Dog. The better soundstage on the Alpha Dog needs something with a better soundstage, and the Alpha Dog seems more congested on the Vali than the Mad Dog. The more revealing capability of the Alpha Dog also more clearly reveals the weak points of the Vali.
* Strong points of the Vali:
- Very quick response which results in very good instrumental detail (I think what Purrin is calling "micro detail"). This is what makes it revealing of source differences. This is the signature strong point which I think is leading some to call it as good as more expensive amps... but read on.
- Smooth treble (a characteristic of tubes) - bright without being harsh
- Good bass response for this price range (better than Magni with my headphones and my music)
* Weak points of the Vali:
- Microphonics (apparently seems to be better or worse depending on luck of the draw)
- Shallow and somewhat narrow soundstage. Imaging seems good but seems somewhat hindered by the small soundstage.
- Mediocre instrumental color - the quality that makes instruments sound very different. I think this is what some call "one note" quality. It is unique to have instrumental detail be this good while instrumental timbre is not. It makes it seem like an outstanding black-and-white picture as compared to a color picture.
So I find the Bellari hybrid with a 1960s German or British tube to have better sound quality than the Vali, due to the better timbre (and roughly equal detail). Neither works well with HiFiMen or Alpha Dogs, IMHO.
I find that the Vali works pretty well with the Mad Dog, because neither has much of a soundstage, so a weakness is nullified. I find that the Vali works pretty well with the MA900, because both have a lack of instrumental color, and again a weakness is nullified. In both cases, one is not losing so much by using the Vali, because the headphones are already lacking that quality (and those qualities cannot be restored by an amp).
Unfortunately, the above is a little complicated, but it took me awhile to figure out why the Vali had some excellent qualities, and yet was often not as good as the more expensive amps.
Of course, this is what I hear with my system, my choice of music, and my ears and so could vary widely from someone else's equally valid impression.