My friend just received his HA-1 on Friday and I went over for a listen yesterday (Saturday). For kicks I tried to connect my Samsung HS-3000 Bluetooth headset adapter to the HA-1 while feeding the HA-1 via coaxial digital out from my iBasso DX90. No Go. There is no "pairing/connecting" menu on the HA-1, it just turns the OPPO's BT On or Off and the device you are wanting to connect has to have the menu and functionality to "see" and "connect" to the HA-1. The HA-1 doesn't even require a PIN code, it is an "OPEN" BT connection for better or worse.
I agree that BT headset functionality would be a nice bonus, but if you are looking to stream your networked DSD and Hi-Res files to the HA-1 and then listen with a wireless BT Headset it kind of defeats the purpose. Apt-X is very good quality, but it still is just "near-CD quality" so there would be absolutely no benefit using Hi-Res formats, IMHO.
FYI, the little Samsung HS-3000 BT headset adapter has the apt-X protocol, has a built-in microphone for BT phone calls, and you can connect any headset you'd like via its 3.5mm TRS jack. I've even used my Beyerdynamic T1's connected to it while playing FLACs from my Galaxy Note II (has apt-X as well) and it actually sounds fantastic. FYI, the HS-3000 is about the size of a typical thumb drive...don't know how it can possibly do this, but it does! I'm looking forward to trying it with some decent IEMs.
Back to the HA-1. So we listened to the HA-1 with a pair of Neumann KH120 powered Studio Monitors (balanced XLR connection) and with my T1's, also balanced XLR connection, and his DT-880/250 (SE). The source was my iBasso DX90 via coaxial and his Windows 7 Laptop using Foobar via USB.
The Soundstage/Imaging/Width/Depth are fantastic! There is great layering, separation, and space between instruments and vocals. Vocals, especially Female Vocals, seem very forward/prominent (almost "inhanced" in some way?) but very lush sounding and pleasing. The mid-bass/lower midrange region seemed a little bloated to me, which seemed to mask some extreme detail that I am used to hearing through the same setup except through my 2014 Audio-gd NFB-28 (with USB TCXO upgrades).
For example, on the Steph Johnson Trio's "Nature Girl" album (16/44 WAV), Steph's vocals are very centered, very prominent but Lush (really nice)! However, the detail that I'm used to hearing in the acoustic double bass and Rob's string plucks and slaps just isn't there compared to the NFB-28. Same goes for Fernando's brush and stick work on the drum kit (cymbals and snare in particular)...the extreme detail is subdued or masked (maybe by the slight mid-bass bloat) compared to NFB-28, and their images are not as sharply-focused to a particular point in space with the HA-1...image placement is correct, and there is a sense of separation and space, but there is kind of a diffuse "halo" around the instrument, sort of a "soccer ball" size image as opposed to a "baseball" size image.
These qualities were immediately apparent, so I then listened to the "Nature Girl" tracks with my T1's plugged directly into my DX90 and the extreme detail and shimmer and decay of the cymbals, along with less mid-bass bloat and a bit "sharper" or "tighter" image focus was back. IMO, the DX90's and NFB-28's presentation is more "real" or lifelike compared to the HA-1. :-/
Norah Jones "Come Away With Me" album in DSD seemed the same...very lush and prominent/centered vocals (very nice) but not quite the detail and focus in the rest of the presentation. Also the same conclusion with Will Knox's excellent "The Matador and The Acrobat" album. I should've remembered to try the new Head-Fi/Chesky Ultimate Headphone Demo Disc, but forgot and time ran out. :( I'll have to setup another listening session and compare these setups again.
Now, we weren't able to compare the HA-1 and NFB-28 side-by-side, but I am extremely familiar with the Steph Johnson and Nora Jones albums, and I was a former drummer & saxophonist so I think I have an acute or "good" ear. These are just My Personal First Impressions with components and sources that I am familiar with, so take them with a grain of salt. Obviously, the HA-1 hasn't had time to "burn-in" yet, so I don't know whether to expect any changes in sonics or not with time.
/flame suit on!