Great review! I have one personal advice: Please try the Luxman DA-200 if you have a chance. It's more expensive but that is the best amp/DAC combo that under $4000. Luxman's stuff is quite suits TH900 or Denon cans. 
Headphone Reviews and Discussion - Head-Fi.org
archeryc
andyj34
Very good review. Admittedly I'm a newbie to the world of headphones. I'm sure you've been asked this question many times but would a headphone amplifier with a external DAC actually improve the sound quality for my set-up; I have a AKG 450 (on-ear) and I mainly listen to music either encoded at 320kbps MP3 or Apple lossless on my IPAD. Admittedly the setup is far inferior to yours but it has been my observation that more you spend the more subtle the increase ... any ideas?
Audiowood
Thanks anakchan for the review.I almost bought it but was holding back. Thanks again it was very informative.
AnakChan
@archeryc, a friend of mine (and a Head-Fier actually) has the DA-200. I could see if I can try my HP-A8 side-by-side with his DA-200.
@andyj34, different audiophiles and enthusiasts have different philosophies about the topic. Each person's hearing at a particular moment in time is also different - I know my listening skills and tastes have changed just within the past year. Then finally is expectation on how much change is acceptable. My personal philosophy is I'd actually pick the headphone's sound signature as primary. If I didn't like the sound of a pair of headphones and was seeking something "better" (to my ears), I'd change headphones first. Thereafter, the DAC, Amp, copper vs silver cables, lossless vs lossy, etc. are secondary in varying levels to enhance the signature of the headphones that I like. Why in varying degrees of enhancement? Some headphones improve easily with such additions, whilst others are already tuned well that external enhancements provide little retuns.
@Audiowood, I've been reading your posts and respect quite a lot of your opinions. Looking at your profile and experience, I speculate that the HP-A8 probably wouldn't satisfy your SQ desires as much as say the higher end Eximus DP1's or Invicta would. At least in my personal scale of DAC Amp, I'd put the HP-A8 as a mid-tier. I noticed that you have the Rx Mk3 as I do. For fun, I did compare and contrast the difference between the amp section of the HP-A8 vs the Rx Mk3 and they were very similar. Except for the Rx Mk3's initial channel imbalance at the lowest volumes, this has given me quite a bit of respect for Rx Mk3 to be comparable to a proper desktop amp.
@andyj34, different audiophiles and enthusiasts have different philosophies about the topic. Each person's hearing at a particular moment in time is also different - I know my listening skills and tastes have changed just within the past year. Then finally is expectation on how much change is acceptable. My personal philosophy is I'd actually pick the headphone's sound signature as primary. If I didn't like the sound of a pair of headphones and was seeking something "better" (to my ears), I'd change headphones first. Thereafter, the DAC, Amp, copper vs silver cables, lossless vs lossy, etc. are secondary in varying levels to enhance the signature of the headphones that I like. Why in varying degrees of enhancement? Some headphones improve easily with such additions, whilst others are already tuned well that external enhancements provide little retuns.
@Audiowood, I've been reading your posts and respect quite a lot of your opinions. Looking at your profile and experience, I speculate that the HP-A8 probably wouldn't satisfy your SQ desires as much as say the higher end Eximus DP1's or Invicta would. At least in my personal scale of DAC Amp, I'd put the HP-A8 as a mid-tier. I noticed that you have the Rx Mk3 as I do. For fun, I did compare and contrast the difference between the amp section of the HP-A8 vs the Rx Mk3 and they were very similar. Except for the Rx Mk3's initial channel imbalance at the lowest volumes, this has given me quite a bit of respect for Rx Mk3 to be comparable to a proper desktop amp.
archeryc
AnakChan, what do you think that Weiss DAC202 can do for the TH900? I found one review says that the TH900 sounds awesome with the Weiss DAC202 headphone output.
