A90/E30 stack with either the Ath R70x or Sundara (both balanced) is perhaps the ultimate midfi. I let ROON play and choose Jazz from Tidal while I work on my desk and it is awesome!!
I got the A90 to replace the Schiit Jot and I can say it is definitely an upgrade when it comes to clarity and neutrality. A90 is clear as glass. But there is something about the Schiit Jot that makes me want to keep it along side the A90. I don't have audiophile vocabularies to describe the A90. However, I can confirm that the expert reviews are true and I do understand why they all claim that A90 is the best amp out there in the sub-1000 dollar category.
With A90/E30 the pianist, the drummer, the guitarist, the fiddler are all in the same room with me as I do my work.
Some people complain about noise when connecting from the RCA. Thankfully I have not faced such issues. The background is a total and absolute blank.

I have used Focal clear Mg with these DAC/AMPs. My observations and usage may not be that of a sound engineer or that of an audiophile, but will benefit a normal listener looking for sound quality who is willing to spend that extra bit. This can is definitely a neutral one which tends to lean over a warm tonality. What I liked the most (a feature that stands out ) is its bass that sounds so natural as if the drummer is right in front of you and the mixer did not add his extra bit while recording. You can even distinguish the second drummer. Bass has reasonable extension to the sub level, and does not bleed into the mids. Mids are good and Diana Kralls and Natalie Merchant will sound so good that one can hear their whispers. Coming back to bass, it is fast and has good slam. Listen to Batshit by Sofi Tukker, Billie Jean by M.Jackson or Mellow my man by Roots in MQA to feel the bass of this can. Treble timbre is questionable and has something lacking in a specific range of frequency. Guitars of the blues are forward and close to the ear. However there is no distortion or sibilance and is smooth.
Sound stage is wide (180 deg and forward) and I felt it has more depth than width. Imaging is excellent where you can pin point the instrument . Instrument layering, separation and details are excellent. Listen to AR Rahman - Khwaja mere Khwaja in tidal masters to experience it. Focal provides you good 1/8” tangle free SE cables with ¼” adaptor and also with a 4 pin balanced cable. It comes with a nice hard case with pockets to store the cables.
The D70s sound is neutral and warm and A90 is transparent . A90 is quiet powerful with three distinct gain switches (L/M/H). Treble becomes much smoother at low gain, but at H adds colour to the timbre. It drives focal clear mg (55 ohms impedance) at 9 O clock at M Gain and at one O clock with L gain for a 24 bit/96-192 khz songs using balanced input and output cables. Balanced 3 pin topping TCX 1 cable is a good accessory (Unfortunately topping does not supply this with DAC or Amp ) to consider though pricy. Dac as well as amp can also be used as a pre-amp should you drive an external speaker . A90 can drive 7.6 W @ 16 Ohms and 1 W @ 300 Ohms per side. .
D70s / A 90
Pros : 1. D 70S Clear, smooth with no distortion 2. Variety of Input – output options 3. A90-Amp Power.
Cons : 1. MQA increases price.

I am using a90 +d90 stack with Beyerdynamic T1. Absolutely stunning transparency and clarity. I was using chord mojo but I felt it did not deliver enough power to my T1s.

I use this amp with the Lcd 3 . Its a treat. My headphones are breathing again. Why i say breathing again because with the earlier amp I thought that’s the best sound i can get from my headphones. My only wish was if i could have got the option of the silver one .

This is one of the better headphone amps out there at given price point and more. It has all kind of inputs and output options too. Also it has oodles of power that can drive almost any headphones out there except some planars or vintage ones.

This amp pairs very well with ESS based DAC's like Gustard X16 or similar ones. especially planar HP. the details / micro-dynamics / bass rumble everything is so engaging that it is difficult to put down the HP.

Only gripe is that this is very picky of DACs. Does not pair that well with R2R or multibit DACs as good as ESS ones. So choose the partner wisely if you are planning to pick this one up. It just kicks the bottom with the right combo.