Nice review.

I have the answers now, thanks @twister6 for your wonderful review!

I've been very happy with my HA-2 so far. I dont yet have the knowledge or ears to fully appreciate it, but It'll come in time.

Nice review.  Can you use the oppo ha2 with the older ipods such as the classic via the old lod?

Great review! Considering getting this to drive some Earsonics Velvets

Excellent review, a pity I have just bought a TOPPING NX1 Portable Audio Amplifier for my wife!

@GLM101 : look at it this way, you saved $260 and now you can treat yourself to a new set of headphones

Great review sir, I am tempted to get this amazing gadzet.

I am looking at OPPO phones for Spotify. Do the list which of their phones are HA-2 compatible? Is the HA-2 use system wide on your phone? By that I mean any app like Spotify can play through it.

@Gino : any android phone supporting USB OTG is compatible, and obviously all Oppo phones will. There shouldn't be any limitation of what you can play.

I had half an hour to play with the Oppo at my local dealer and tested it with an iPod Classic and an iPhone 5. I used Etymotic HF3 in-ears for the audition.
Regretfully, I could not detect any appreciable improvement in SQ, especially with the iPhone, that would justify spending Aus $450 on the device.
I was very disappointed as I had gone to the store expecting to buy the HA 2.

In response to 'davidcotton', yes, you can use it with an older iPod Classic but it will not extract a digital feed from the Classic. In this instance, it acts as an amplifier only, taking an analogue signal from the headphone socket.
I strongly recommend that you audition before you buy as I was not impressed overall.

Twister, this review looks promising. I was planning to buy this portable amp for my Bose QC25s (good quality sound + good NC), do you think its a good choice?

I had the Oppo HA-2 and used it with my iPhone 6 for a couple of weeks.  Was not impressed with the SQ versus output directly from the iPhone 6, so sent it back.

Oh Gawd @SallyMae @tmarshl  I hope this was something else that was making your listening session less than stellar. I just ordered it before seeing your comments. I based my decision off of all the reviews I was seeing, and wanted to use this as a headphone amp for my desk as well as portable. Using the DAC on my Audioengine A2+ would be nice as well.

@twister6  where'd you get that right angle USB cable?  I've been looking for one for awhile.  Thanks!  Great review too btw.

@Bazirker : http://www.ebay.com/itm/10cm-Right-Angle-to-Left-Angle-Micro-USB-Host-OTG-Cable-4-DAC-Digital-Amplifier-/301669713346?hash=item463cea85c2

You talk about iOS and Android compatibility. I own a Nokia N8 Symbian phone which I still like to keep. Can I use the HA-2 as a DAC/amp with that phone or only the amp section? Thanks for your expansive test.

You talk about iOS and Android compatibility. I own a Nokia N8 Symbian phone which I still like to keep. Can I use the HA-2 as a DAC/amp with that phone or only the amp section? Thanks for your expansive test.

@yawg : hard to tell without testing it.  It's compatible with iOS and android, probably not compatible with other OS so you might be stuck using it as amp only.  And to be honest the amp is not the strongest part of this device.