Interesting. I’ve been using a Cayin n6ii as my main for just about a year and a half now so I don’t have experience with a wide variety of sources with any of my more recent IEMs. Cayin uses Campfire IEMs when they tune their daps so there is likely a pre-existing synergy there. My favourite source for my CFA IEMs, though, is my PAW S1-- crystal clear, just a touch of warmth and an inky black background. The detail and resolution of my Solaris and both versions of the Andromeda I have tried get elevated through the S1. Conversely, the MEST was practically interdimensional through the E02 board on my n6ii but sounded flat and dead through the S1. The importance of good synergy with any gear has been one of the big lessons of 2020 for me.
In general,
based on my experience, I would say that in-ears are far more sensitive to DAC / AMP combinations than headphones.
If I had to compare my Andro’s to headphones, I might consider the focal series:
MV10 in the direction of Utopia
The “golden” in the direction of Clear
The “originals” in the direction of Stellia
The comparison is of course nonsense, but it roughly represents the tonal alignment.
PS.: I love mine too 
I get what you mean. I find the Utopia comparison interesting. I have very limited (as in next to no) experience with full size but I have been very curious about Focal headphones for a while, in particular the Utopia and the Clear. My favourite headphone I’ve demoed so far is the Verite C, which sounded to me like something of a Solaris SE in headphone form (not literally, but with some similarities).
Edit: Have you heard the 2020? It’s the most similar to the MW10 to my ears. I haven’t been able to compare the two directly but my gut and impressions of others suggest to me that the MW10 is the 2020 with improved technicalities as well as more sub-bass and top end sparkle.
It’s interesting to see such variations in sound from all of those sources with the CA IEMs, especially among the ifi ones. I think there’s a risk of concentrating on output impedance when it comes to pairing sources with Campfire Audio’s BA IEMs, since this gets discussed so much on the forums, and of forgetting that other factors are also at play.
I got my Andro 2020 back in the summer and picked up an Astell and Kern Jr. to pair with them as its OI, at around 1.5 - 2.0 ohms, I believe, is well-suited to my listening preferences. (The Andro 2020, already a darker IEM, gets far too bassy and dark out of low OI sources for my tastes; the original, less so, because of its treble sparkle). The sound signature was just right for me, making the Andro 2020 a little less dark and closer to neutral, but the macrodynamics were really lacking, so the overall sound was too soft and dull.
I read the highly laudatory impressions of the Sony ZX2 with the original Andros and picked up one of these DAPs for the 2020 and it’s likewise a wonderful, synergistic pairing.
Weirdly, though, the ZX2 was a hot mess with the Solaris 2020. I couldn’t put my finger on the problem. Here are impressions of the pairing, which I posted on another forum:
I have no idea about what was going on with the ZX2 but the Solaris 2020 sounded all kinds of wrong with it (and I had all the sound adjustments disabled). The bass could be inconsistent, disappearing on some tracks but being strong on others. At times this oddness seemed to go beyond changes to frequency response with a higher Zout source (I realize the dynamic driver isn’t affected by output impedance). Electric guitars and vocals, for instance, could also become too faint at times. My sense is that the ZX2 and Solaris 2020 somehow made the mids—or perhaps the upper-mids, more specifically—sound recessed. Perhaps. I don’t know, it was weird (or my perception of it was).
I completely agree with @jrockwell about the Lotoo Paw S1 being an excellent, synergistic pairing with the CA IEMs - and I owe him many thanks for giving me some great advice before I picked up my Paw S1 a few weeks ago. I can’t find its OI listed anywhere but my sense is that it’s probably somewhere in the 1 - 2 ohm region since my Andro 2020 doesn’t sound overly dark with it. Rather, it’s quite neutral, and it has the qualities jrockwell describes. I’ve not had the chance to listen to it properly yet - or, at least, critically and studiously - but I will say I’ve noticed that its sound varies according to whether it is being connected to a MacBook Air vs. an iPad or iPhone (it sounds worse out of the latter).
Once the holidays arrive and I can devote some time to listening properly, I’m looking forward to doing a comparison between the ZX2 and the S1. Thanks again for the advice @jrockwell!
I can’t find its OI listed anywhere but my sense is that it’s probably somewhere in the 1 - 2 ohm region
Not sure if you’ve compared the 3.5mm and 4.4mm outputs of the S1, but, to my ears, the 4.4mm doesn’t sound as good with the Andro 2020. To me, it sounds a bit darker and there’s a little drop in resolution. Could be explained with lower OI, but who knows !
I’m pretty sure the OI of the 4.4 on the S1 is 1.2 and .6 or .9 on the 3.5…I don’t remember where I got this from as I can’t seem to find it now to verify.
Interesting ! I don’t really know why Lotoo wouldn’t release that specification anywhere.
They must have…I know I’ve seen it somewhere. I remember comparing at the time and finding out that the OI for the 3.5/4.4 on the S1 is the same as it is on the P6K.
I don’t know why Lotoo hasn’t released the OI details, it’s not as if they’re shy about providing other specs! I searched pretty thoroughly for it a couple of months ago - I was leery about buying it if the OI was too low - so it’s possible that information has been released since then. I also asked on head-fi and no one could provide an answer. I ended up taking a risk on a used S1 from Musicteck assuming that I could sell it on without too much of a hit it if it didn’t work out. But it’s fine for my tastes.
That’s interesting @Titienne about the difference between the 3.5/4.4 outputs and is well worth noting, thank you.
I’ve compared my S1 against the iPhone with dongle, the Fulla 2, and the Magni 3, and all have an OI below an ohm and closer to zero, IIRC, and all sounded much darker than the S1. (This is without using any of the preset EQ settings on the S1).
I was somewhat late to the Andro club but the 2020 (and later the MW10) made me a member.
I’m late to the party, too, but my excuse if that I’d been saving up to get my Andro 2020 since 2018. Now I want to save up again either for an OG version or the Gold or @jrockwell’s MW10 when he decides to sell it in a couple of years’ time 
(I’m just joking). Too many Andro choices, too few of the right lottery numbers!
Christmas came a day early-- I received the Canadian VE tour package and also a Leonidas for my MW10. Canada Post exceeded expectations for me today.
Edit: I reserve the right to reverse this statement later but holy balls if this cable isn’t doing it’s best to make me a believer…I’ve gone between cables a few times and I’ll be damned if the Leo doesn’t clean up the highs and improve perception of micro-details and textures.