Ok, so I did a bit of research that may be helpful to you. I paired the Oppo HA-2 with the MrSpeakers Alpha Prime and the original T5p and here's what I found:
The HA-2 is mated to my old iPhone 5S running iAudioGate playing 44.1kHZ/16 bit FLAC files. I played a variety of music from Hip-Hop, EDM, Rock, Alternative to Jazz and Pop.
The HA-2 had no problem driving the Alpha Prime while using the high gain setting. The Alpha Prime sounded good. The HA-2 tamed the somewhat peaky highs, the mids were present and somewhat forward, and there was plenty of bass but it did not encroach into the mids. The Alpha Prime isolates very well, but the price for the isolation is a small soundstage.
The T5p is obviously very easy to drive and the low gain setting was more than enough. The T5p sounded great out of the HA-2. There were no surprises. It has the great soundstage (for closed headphones), the clear vocals and the impressive highs that are never sibilant. On the negative side, the bass is missing and they do leak sound and do not isolate that well. Interestingly, using the HA-2's bass boost, the low end wakes up and makes the T5p's much more enjoyable while listening to Hip-Hop. Overall, the bass did not intrude into the mids much. However, I'd use the bass boost selectively for Hip-Hop and EDM and would probably leave it off for other genres.
One last thing, if you wanted to order the Alpha Primes, MrSpeakers ships worlwide, so you're covered there.
Here are a couple of pictures that may be helpful for comparing how the Alpha Prime will look like with the HA-2 versus the T5p.