Yeah, well, I can understand how some of the reviewers get the impression that these first rate amps don't deliver. I was myself in such situation twelve years or so ago. Bought new headphones: AKG K701 - presumably reference grade - and then a Violectric V100 amp. Boy, was I disappointed! Sound quality was so poor, I really was devastated! Then I discovered the brand beyerdynamic and had the opportunity to listen to some of their headphones. I finally bought a pair of DT990s and boy, the difference was night and day!
I've learned the following things:
- Headphones make the most impact concerning sound stage and sonic impression. Most people that complain about poor bass or sound stage or too little power should just switch to another headphone brand (and impedance, that is) because they probably have not the right headphone gear for their needs. Those AKG cans were not to my liking. The sound stage of the DT990s kicks ass and I still own and use them (after ten years of daily use). (But I know some people here have a more profound knowledge of headphone gear – I've never listened to planar magnetics and I have no idea if those really are audiophonic heaven or if they're just marketing hype...
)
- A good DAC is always a good investment and should be carefully chosen - don't trust your PC sound card output, it's just not delivering
but don't invest too much initially, you can get good quality for little money (as Amir's tests show)
- Headphones amp is a must if you want your headphones to really shine, not as important as no.1 and 2, but you can accomodate for that by buying gear that implement both functions, DAC and headphone amp. My personal pick in this category would be the RME ADI-2 DAC right now for endgame quality gear. (I still own the Violectric HPA-V100, it's a solid amp with marvellous workmanship (probably not endgame in these days but built like a german tank!).
So these reviews stating
"Its OK...doesn't have much amplification power. I returned it."
seem to have just picked the wrong equipment for their needs and have not considered the whole audio chain.