Olina 
If you wanna stay on single DD for the timbre and coherency.
I had the NW-A105 and I can’t recomend it. Take a look at the Hiby R5 Gen2 if you have the budget!
Yes, the best. I was going to sugest it but you can’t the need the IEM isolation, as they are open.
NW-A105 especially in EU is probably the most spectacularly bad Sony DAP. It had very limited power output due to the regulations (the limit which you could not take down) + terrible battery (which you could potentially get better by heavy debloating).
NW-A55 is a different story, especially modded with Mr. Walkman FW. I am currently in hospital rocking some new 2022 albums I bought (new Big Thief album is amazingly mastered record!) with it and MEST/Rider 1 alternatively and haven’t charge it for almost a week (I never turn it off as well). The usability and portability is on top level. The Sony “mood” playlists are also something surprisingly great. I always missed with non-streaming players those Discover weekly/daily mix playlists from spotify and shuffling the whole library where I have every single genre on earth was never a good idea. Now the moods proposed by Sony’s algorithm are really fitting and there are just a few mistakes if any that I found.
Now I am not saying R5 II would not be a better DAP (as I haven’t heard that at all), but it is 3,5x times more expensive + the size is making it less usable than I would wish (I 3d printed the shell when I was deciding on what DAP I would like to go with). R5 Saber was much better in that category, but unfortunately it is discontinued and nowhere to be found in EU
That will depend on what he wants to power + the need for Android. I should try to get a55 and use the fw one day 
Our latest YT video and first look of the Audeze Euclid In-Ear is live!
We also announced with the support of Audeze we will be giving away one Euclid to one lucky winner! The Contest link is in the video description. Good luck!
Thanks for the tip!
That’s what I read on many forums. I’m a Canadian and everything is so pricey and that’s why I was looking at the NW-A55 with Mr.Walkman mod! I have a large FLAC music library and don’t really need Android. I prefer a good sounding DAP and a long lasting battery.
Does it have enough to power Olinas? 
What’s the next single DD on your list as an Olina improvement? (no matter the budget)
I prefer isolation. When commuting or working, music is a way to get in my own world, disconnected from my environment. I’ve been using openback headphones and earbuds for a while now and they don’t offer the same experience as IEMs.
How much is the rikubuds?
In my opinion A55 would drive every IEM fine apart from maybe some very hungry planars like P1. I would check S12 when I would be back home, to confirm how it handles that, but it played ok straight of my 3,5mm phone jack as well, so I can’t imagine that being a problem.
Then there is “scaling with power” concept, but I never experienced that myself, so cannot tell. If you calculate the raw power needed for some SPL you would see that most of IEMs do require only a fraction of PO that most DAPs and dongles can provide.
You have stuff like this Questyle M15 with rated 80mW@32Ohm which supposedly powers Sundara, but it costs 250$, so it could be taken more lightly by some reviewers/user because of that fact 
Dark Magician, Zen Pro. IE600 if you want that more V-Shaped, but I doubt it with your library.
With your library I would go Zen Pro + R2R (like Cayin RU6 dongle) and call it a day. Or earbuds.
Fiio FD7 might be a consideration but I’ve yet to hear it.
I wonder how the Elixir or Vortex would compare to the options you listed.
Short impression - Elysian Diva
I wish this was a tribrid, but then I probably can’t afford it. Briefly compared it to Monarch MK2 and the latter doesn’t have the wow factor to entice me - all around good/“safe”
The A55 with the aftermarket firmware is pretty nice imo. Not a bad pic! 
There are many choices and since it single dd are not real costly on the average. You read reviewers and as you try iems they like you can decide if your taste in sound is similar. I have a tendency to wait for Chris to review because we may not agree all the time I am confident if he recs it I will like it. NYMZ appears to be very good but I have to try one of his top recs to evaluate how we evaluate sound.
It’s been a long time since I had the DM in ear… but I’m pretty sure the Vortex pulls off much of the same magic from my memory. Different focus to the Vernus, and I prefer it to the Vernus. So it’s officially the best single DD I have any useful memory of.
Very strong magnets, solid driver material, very skillful tuning. Full of energy (bite) and detail, but yet hasn’t been sibilant once for me, whether that be with vocals, cymbals, etc. I can’t actually say that for the DM, but then I never got a super good reliable fit with them. Vortex has one of the best fits for me because of the small shell and the nozzle length being just right.
As you know, I don’t shill Penon for Penon’s sake. I’ve found their thread uncomfortable lately for how much praise the Globes have been getting as for me they have a few compromises.
Edit: I haven’t listened to the Serials since I got the Vortex because I want to build up a clear idea of the Vortex, and because I’m enjoying the way it handles my library - maybe more of my library than the Serial is truly strong for. When I do listen to them again I’m expecting them to be on par, just with better sub bass and a more laid back tuning. Complementary giants, that can both be owned for less than many EST tribrids.
I probably won’t get my Vortex for another week so would love your thoughts on the Serial and Vortex. My gut tells me they will be very complimentary.
I find the praise on the globes a bit odd too. In the price range I think there is so much better stuff.
It wasn’t bad per se but it only jived with like 10% of my library.
+1 about head-fi. Its a great resource for information but new releases are always crazy hype trains. I only started looking into the Vortex after your review cause I trust your opinion.
What shell design/colours did you go for? Can’t really tell what the darker version looks like from the crap images on Penon’s website.
There are better pictures of the head-fi Penon thread.
Yeah probably - but I can’t tolerate half the shilling crap that contaminates the thread, so I’d rather avoid it as much as I can tbh. No reflection on Penon’s IEMs though, bought the Serial because the driver config had me curious to see how it would differ from the UM 3DTs and really like it for a fair bit of my library. And the Vortex definitely has my interest.
That means an awful lot. I hope it meets your expectations!