[Mr Vicarious]

 
 
 
 
HA-INFO U2 Plus
 
 
Great little USB DAC, with impressive specs for the price which is £45 ($70):
 
AD1852 DAC
Tenor USB TE7022
ALPS Pot
TI 6120A2 headphone amp
Good quality caps 
 
After replacing the stock op-amp with a OPA2134 and using Sennheiser HD600 headphones (300 ohm) the sound is smooth and dynamic but controlled and with good detail. There's also enough power to drive the Sennheisers to fairly high volume levels.
 
Despite their high impedance, there is very good synergy with the HD600s; however I can't vouch for other headphones, as there is the possibility that this unit may have a high headphone output impedance, which means low impedance headphones - which are usually most suitable for this type of amp because of the ease with which they can be driven - will may not sound as good. However this is speculation on my part, other users may be able to confirm or deny this.
 
Despite this reservation I'm surprised how this unassuming little unit can manage to sound so authoritative and musically satisfying (with my headphones) for such a low price.
 
One thing worth mentioning is that the HA INFO needs at least 60 hours 'burn-in' to start sounding its best. At the beginning when plugged in from new, the unit sounds quite hard and cold. After the burn-in process (I gave it 90 hours in total), it opened up nicely.
 
  

 

[coolcat]

It sounds so good < I just got the modified version of it from my friend
It can drive HD800 and HE5 easily ,sounds even better than my HM801 unbelieveable
 
 
I would say the best value ever for me is this combination
Creative aurvana mod with cardas cable and a little mod in side (total cost = 133 $ ) + modded HA U2 Dac amp (cost total  around 150 usd. I'm not quite sure cuz he just build in a small amp inside ).
 
I will listen to it with my JH16 tomorrow

 

[Mr Vicarious]

Can you tell me what mods exactly your friend did to the unit? I would be really interested to know.

 

[coolcat]

I will ask him,but I don't know if he will answer (even though we're friend ),he likes to keep it secret.
I think he can tell me about the opamp and how he built his amp in Generall,if I get some information from him ,I will tell you

 

[madnanny1]

hello mate am thinking of buying the ha info u2 , is it in your opinion a good buy and where did you optain your op amps. thanks

 

[Mr Vicarious]

Yes, I definitely recommend the HA INFO. The op amps can be purchased from eBay.If you buy it, give it at least 60 hours burn-in to reach it's full potential.

 

[wat12]

Quote:

Can you tell me what mods exactly your friend did to the unit? I would be really interested to know.

 
Hi, About the answers for your Questions.(Sorry for my poor English )
..... First of all I've done hardly modded to every thing I own for the best performance of itself can do. ( I means the chips, the circuits and the topology)
 
1) Find out the weak point and Decrease it.
....The power supply ...>>> To change some parts with the power full ,Faster and make sure the current can smoothly  flow.
....The signal parts  ....>>> To upgrade, replace with the more good sounding parts
2) As my modded concept above  ,,, thinking about  "How to upgrade  the overall performance and setting the GOAL  (ex. 10X worth of it price) "
.... Do it follow my dreams and enjoy to got the result.
 
Note: My next step modify.
Using the external power supply  0-28V 1.2A Linear Regulator (and review the amplification gain of the amp. stage) for more power full  and enjoy to drive the HE6
 

 

[Keller1]

I just pulled the plug on this sucker, what can I expect, i've never owned a DAC/AMP before. (Except fiio e3, which was awesome) I'm using a pair of old, bassy russian orthos - TDS5M.

 

[petehutch]

Interested in buy one of these but I'm not 100% confident in the dimensions I'm seeing listed on various site (145mm(L) x 31mm(H) x 75mm (W) - Just looks a lot smaller than that so wondering if anyone would be kind enough to confirm these for (unfortunately size is an issue for me).
Thanks.

 

[TierAngst]

Anyone know how one of these compares to a FiiO E10?

 

[selphy]

Is it better than MM 02 US ?

 

[Metalboy]

Quote:

 
I will listen to it with my JH16 tomorrow

 
How did it sound with your JH16?
 

 

[zaccio]

I agree it's the best budget USB DAC headphone amp but forget the OPA you mention 

 and put a serious OPA like the Audio-GD OPA-EARTH and you get a true killer amp!
Ok you have to sacrifice some aesthetical but it worth the effort...The sound of stock HA INFO U2 PLUS is quite decent but with the Audio-GD OPA the difference is spectacular

With stock and OPA2134 the cymbal sound like 192kbps mp3, with the Audio-GD it sound like 900kbps FLAC. The modified HA INFO U2 PLUS is even better than my previous setup:Fubar II USB DAC and Little Dot MK4 SE

 

 

[Mr Vicarious]

Much better.

 

[Mr Vicarious]

That's one serious looking op-amp! How much was it and is it readily available?