I must say thatbi have expected little bit more of the product, but even though it is excellent product for the price. It lacks a bit of tube warm sound, but this is probably due to tubes working as preamp, not the amp. I will try tube roll to see the difference. Sound is much better via this little amp. It gives livenes to music and it is very punchy in low frequencies. It has pretty natural sound. Drives my HD580 without a sweat. Only negative thing for me is hard to control volume knob. Since everything is bundled on front panel it is difficult to connect cables too.
Nice product, great sound on my headset!