The HA INFO U2 PLUS USB DAC and Headphone Amp:
The specs are impressive especially for the price £45 ($70):
http://www.ebay.co.uk/itm/250894651278#ht_1296wt_821
TENOR TE7022L USB reciever chip
TPA6120A2 Headphone amp chip
AD1852 DAC
Nichicon Muse caps
Alps volume control.
The first thing I did on receiving the DAC was to change the op amp from the OPA2604 (not one of the best) to OPA2107. I would encourage anyone who buys the DAC to change the op amp as soon as possible otherwise you will not get the best out of it.
I will try different op amps later and post the results.
I've been listening to this for past few hours after 20 hours of burn in and I think this is a great little unit. There's enough power to comfortably drive my HD600 to a very loud level. The sound is detailed, resolved and controlled.I can easily hear into to a complex mix but still be able to simply enjoy the music. It's a little distant and cold sounding but I think this will gradually disappear with further burning in .
Has anyone else had experience with this USB DAC?
After 40 hours burn in:
The sound is opening up further and becoming fuller and slightly warmer.Volume tracking has also improved. This is turning out to be quite a remarkable unit. I will post further impressions during the burn in process.
After 90 hours burn in:
This is really an excellent USB DAC...the sound has matured now and has become slightly mellower and smoother.It's fairly neutral, perhaps a little warm, with plenty of detail with very good imaging and sound staging.It's such a well balanced sound...the ample bass is pretty tight, midband is open and without any significant colouration,treble is smooth and well extended. The only criticism I can make is that sometimes I wish it had a bit more dynamic range and had a slightly 'bigger' presentation but this is only in comparison to a more expensive separate headphone amp and DAC, and to be honest it it does so much right and for such a reasonable price that to make any criticism seems unfair. In fact it does some things better (like instrument separation) better than a few pricier DAC/headphone amp combinations that I have known.
I can confidently say that it is much better than the Aune Mini USB DAC and significantly better than than Audinst HUD-mx1 I use to own .The latter although having a good DAC, didn't have the headphone driving capability (even at high gain) I was hoping for and simply sounded too 'small' and bass light.The former was all about big imaging but lacked resolution and control (through the USB input).Though the build quality of the Aune is superior to the HA INFO, which does have a good build, (apart from the awful volume knob, which I've replaced, see photo), it's just that Aune decided to something special in that regard.
Anyway, best value audio purchase I have ever made (I've been an audiophile for 16 years) and ranks in my top 3 regardless of price (purely on sound quality).
Highly recommended!
Op amps:
I've tried various op amps. Here are my results:
OPA2107... good bass, tight and powerful but treble blunted
LME49720HA...smooth and neutral but a bit dull.Bass could be tighter.
OPA2111AM...lucid,valve like sound but a bit too warm and cuddly for me.
OPA2134...this more humble op amp is best for the HA INFO (for me anyway), very neutral, powerful sound with excellent detailing.
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Edited by Mr Vicarious - 10/12/11 at 4:22pm
and put a serious OPA like the Audio-GD OPA-EARTH and you get a true killer amp!
