I promised that I would provide an update on my impressions of this product which I had the good fortune to win in a raffle at the recent Head-fi meet at Cambridge, UK (thank you Frank of Toxic Cables for providing this amazing prize). As I didn't buy it - I didn't even know what I'd won until I'd got it home - my comments can be taken as pretty unbiased.
I've had it for a week, used it quite a bit and played a wide variety of music though it. Throughout, the music has come from my iMac (ALAC files) via the USB and optical outlets and I've mainly used my Sennheiser HD650s, although I've also given my LCD2s and Westone 4Rs a try. I can't tell much difference between USB and optical - both sound good - but I've stuck with optical simply because it frees up a USB port. I've just used the cheap supplied cable via an adapter.
To cut to the chase, I really like this product. It connected immediately and faultlessly to my Mac and the sound was good straight from the box. I've always been a bit of an audio 'snob' and assumed that to get high quality sound you need separates and need to spend a decent amount of money (my current 'main' headphone rig is a Meridian 588 > Violectric v200 > LCD2) but this product has challenged that assumption. It sounds splendid; very 'analogue' and natural and has handled the wide range of music I've thrown at it with real authority, especially via the HD650s with which it seems to have particular synergy.
It doesn't seem to have any particularly noticeable faults and the sound is un-fatiguing in a good way - it really encourages you to keep listening. Instruments are presented naturally and it does a decent job in terms of imaging too - there's a sense of space and depth that I found really surprising and a good 'black' background. It's the sweetness of the sound that I like best and it manages to make some poor recordings that I normally wouldn't listen to though headphones sound acceptable. But don't be fooled into thinking the sound is laid back; bass is solid, sharp transients have good impact too and it can certainly rock - for example Bliss by Muse has plenty of impact.
As I mentioned it sounds great with the HD650s. To my 50yo ears this as a really satisfying combination and I could see many people being pretty happy with it. On high gain, I found a setting of around 9-11 o'clock was about right. It was fine too with the Westones, but I didn't sense any particular magic. Ditto with the LCD2s which were okay but may be just a bit too much of a challenge for the amp to really shine.
So, in conclusion, I think this is a really good product and excellent value at its price point. About the only thing you can really criticize is the construction which, while well made and solid, isn't especially refined. But I'd rather the money was spent on the sound, and it certainly seems to be here.