Originally Posted by MarcoGV
My experience is that the NAD 3130 (with its 220 Ohm headphone output impedance) works very well with the Q701, while the HD598 does not pair up well with that amplifier---the bass is bloated. This is what one would expect from the difference in the impedance curve for the two headphones. Since you have the HD598 as well, can you confirm that you had similar problems with the HD598 and high headphone output amplifiers?
There are some comments on amazon concerning the Bravo V2 and the K701. The poster likes that combination a lot. It seems that you do not, however. Is the Vali + Q701 really that much better than the Bravo V2 + Q701? Which DAC do you use?
Dang, I totally missed this post.
Bravo V2 just annoys my ears with the Q701. It makes the Q701 sounds a bit too thin and harsh. Too trebly. I would say it's similar to how it sounds with the Magni and stock O2, but not as good.
Even adding a warmer sounding source doesn't help much. I even swapped out the tubes without much change.
I have a feeling the Bravo V2 just doesn't have enough juice for the Q701 or is just bad synergy. The V2 however sounds great with the HD-650.
Vali+Q701 sounds almost as good as the Ifi iCAN and Micro Amp for the Q701. It's not too thin/harsh/analytical, but yet not warm. For the Q701 (ONLY!) it sounds like a more refined Fiio e9, but less warm.
Vali is not a warm sounding amp at all to me. At least not with the Q701. Maybe a very very subtle touch of warmth.
When I compared the Micro Amp + Astrodyne power supply to the Vali with the Q701 they sounded nearly identical. This means mostly transparent without being thin/cold. I'm not a fan of the Vali at all, but it sounds great with the Q701.
Vali is not a good all-rounder amp. I know people shouldn't expect this, but I have to point this out.
Also, sorry I don't remember trying the HD-598 with a high output impedance amp.
BTW if anyone is curious I don't really like the O2 with Q701. It would not make me love the Q701. I swapped out the op-amps and there is an improvement with the Q701 (just preferences). Cost is less than $10! OPA2277 is good. I keep forgetting all the op-amp names!
The only amps I suggest for the Q701 are the E9, Micro Amp, Ifi iCAN and MAYBE the Vali. O2 is just OK with the Q701.
Interesting fact...3 of those use the OPA2134 chips.