Thanks for help!! Overlunge Sir has translated my chinese review into English !!
Here :
Disclaimer: I have limited experience when comes to amp comparison; the majority of amps I came across were mostly DIY or made by local Taiwanese manufacturer. Therefore the following review could lack the perspective of comparison.
A Taiwanese forum (AndAudio) held a group buy for the ATH-HA20 (HA-20), and many said the HA-20 has great synergy with the Audio Technica (AT) headphones. I chose this amp because my current headphone is manufactured by AT, and also I was on a limited budget.
I have used (burn-in) this amp for a month since I modified the capacitors, but I have also spent a fair amount of time to listen to this amp before my mod. Although the mod did not greatly change the sound, some subtle improvement was noted.
Although using sound card as source might not help with this review greatly, I will try to the best of my ability to describe the sound and HA-20's characteristic.
AT's close headphones are known for its overly extended treble, and slightly congested midrange and bass frequencies. But the same time they all have low impedance, therefore I question it is because the lack of current.
When I first connect the headphone to the HA-20, even without careful A/B test, the differences were immediately noticeable in comparison to Emu 0404's headphone out. (Not to mention 0404's capacitor and opamp had been modified).
What struck me first, was the details and the layered sound.
There were details in the music where you had to pay attention to hear, became apparent and just flows into your ear. My ATH-W11JPN's ability to bring out the detail were highlighted. The completeness of the details were also improved. Allowed me to heard the whole spectrum of sound produced by the instruments, things like picking of the string. Unlike the congested sound straight out of the sound card.
The elevated level of sound layering were impressive, the space between the instruments were larger, the drum which were placed left/right before, now has been given the front/back dimension. The separation between vocal and background music is greater, the background sound no longer interfere with the complete sound of the vocal.
The next thing I noticed was the sound were given more flesh. The timbre of the instrument became more natural, and the instrumental pieces was more pleasing to the ear.
The downside being, where the vocal portion of the music now has more prominent sibilance, and lack the gentle sound before using the HA-20. Problem occurs when there are metallic instruments, at some passage it would exaggerate the shrillness and some passage it would tame the shrill (where original music were problematic). I put this down as the amp has poor ability to control the treble.
As for the tight/congested midrange, HA-20 puts the midrange more forward, and brings out more details to the voice. AT headphones are known for their approach to female vocal, with the amp, the female vocal become sweeter and more moving. (Except the sibilance mentioned previously.)
HA-20 has good performance in the bass, because it controls the quantity of the bass. (Bloated bass is not my cup of tea) Although the reduction in quantity, it adds more texture and airiness. The bass has a bouncy quality where as the hard 'thump' without the amp. As for deepness, I did not notice much difference.
The above sums up my impression/review of the ATH-HA20, because I have no amp I can do the comparison with, please use it as a reference. In my opinion, HA-20 is an amp that's worth trying at this particular price range.
