General Information

The A90 is an ultra-high-performance headphone amp that can also work as a pre-amp. It comes with three gain settings and has great performance numbers including <0.00006% THD+N, 145dB DNR, <0.2uVrms Noise, < 0.1-ohm output impedance, and 7200mW x 2 max output power.

The A90 comes equipped with NFCA modules (Nested Feedback Composite Amplifier), which along with ultra high-gain feedback technology provide excellent AC and DC performance. High output current capability of the A90 allows it to drive low impedance headphones with ease. Furthermore, ultra-low noise of 0.2uV and high dynamic range of 145dB drive the most sensitive IEMs without producing any audible noise or dark background.

For outputs, the A90 comes with a 4-pin XLR, a 4.4mm Balanced, and a 6.35mm Single Ended port. The Single-Ended 25V pp with Balanced 49V pp high output voltage along with high output current and less than 0.1-ohm output impedance, A90 is compatible with a wide range of headphones. It also comes with the three-step gain setting and a wide variety of sensitivity settings that allow the amp to drive sensitive IEMs to power demanding headphones.

Being equipped with NFCA modules, A90 can also work as a pre-amp. In pre-amp mode, the 20ohm single-ended output and the 40-ohm balanced output impedance make it easily compatible with various power amps. You can also connect the A90 with the D90 DAC in pre-amp mode to drive active speakers and create a high-performing sound system.

Latest reviews


New Head-Fier
Pros: Loads of Power and Current, Drives everything, Value, Transparency, Details, Subtle smoothness
Cons: Transparency, Slightly soft sounding, Might make you buy more headphones and iems
To me topping propelled themselves into the market out of nowhere and claimed their place to the throne with the A90. From all the praise I heard about it to hearing it for myself and realizing why there was all the praise, it was exciting. You flick the switch on and it responds with a green LED light, or well orange depending on if you switch to pre-amp mode.

The unit feels in a word: solid. Feels heavy when picked up and the rubber feet on the bottom don’t feel like they’ll move out of place or come off like on the schiit magni 2. The knob is smooth and gives a feeling of ease to turn. Speaking of turning volumes, you’ll get the full range here. From sensitive iems to full size behemoths like the Abyss 1266 phi TC, and it’ll all be driven well. That is something of no small feat.

Now finally on to the sound:
I wish I had a lot to say but I don’t. It’s clean, extended, exciting yet soft and ever so slightly mid-centric. It delivers a lot of detail and good air up top too while at it. But that all gets hard to determine because it’s just so damn transparent. It has those sonic qualities I talked about but it injects itself into your chain so subtly. It takes the characteristics of your DAC, source and just tends to disappear. You eventually forget you are listening to an a90. Highlighting all the other components in your chain. One thing I will say about it though is it’s best when used through the balanced jacks for harder to drive HPs or even higher end iems. The difference in overall impact and involvement of the sound will make you want to plug shut the single ended jack for good. I’d best recommend pairing a warmer or darker sounding DAC to go with the A90 for best results, otherwise if your DAC is strident or bright like a lot of DACs can be, the A90 will not hide it in the slightest. But depends on you if you like that or not really. For me personally, I prefer a smoother sound over a brighter one.


Reviewer at Sound Perfection Reviews
Formerly affiliated with HiFi Headphones
Top performing amp for a midrange price
Pros: Clean, linear, versatile, powerful
Cons: Some users have reported noise when using RCA inputs
Firstly I would like to thank Topping for sending me this sample to review.

*disclaimer: This sample was provided for the purpose of writing a review, no incentive was given to write a favourable review. All opinions expressed are my own subjective findings

Gear Used:
Keces S3 / Topping D90 > A90 > HiFiMAN HE6 SE / German Maestro GMP400 / Various IEM


Tech Specs:

MSRP: $499

Packaging, Accessories and Build Quality:
The A90 comes in a similar box as the D90, it's a simple black affair with very good foam padding inside to keep the unit safe during shipping. It really is as simple as it gets, but the box feels sturdy and does the job of being nice to open whilst offering excellent protection during shipping.

Accessory wise the A90 comes with a jack adapter and the power cable. To be fair though the A90 is just a headphone amp so there aren't really any accessories needed.

The A90 is similar in build to the DX7 Pro and the D90, with smooth edges and a good size chassis for desktop use. There are 3 switches on the front along with 4.4mm and 4-pin XLR balanced outputs, 6.3mm single ended output and a volume knob. On the back you have RCA and XLR inputs and outputs, the power cable socket and a power switch. On my unit everything feels very well put together and solid, the inputs and outputs are all tight and the switches have no play in them.

The A90's main function is as a headphone amplifier, and there are few frills to the amplifier stage. You get 3 gain settings, a switch for balanced/single ended inputs and a switch for the power (Off/HPA/PRE). There are both balanced inputs and outputs, which allows you to use the A90 as a pre-amp for desktop speakers.

To benefit from the full power ouput of the A90 you should use a suitable balanced source along with the balanced output into your headphones. The gain settings and low noise floor, along with low output impedance mean the A90 is also very capable when using IEM's, just be careful with all that power on tap.


Subjectively the A90 is very clean and linear with a hint of warmth. The great thing about the A90 is that you can pretty much power most headphones on the market with it, and it serves as a great amp to listen to but also as a great benchmark. For it's price range I am really impressed at how detailed and clean the A90 is, it amplifies the sound without altering it or adding much of its own flavour.

Using my GMP 400 which are quite a neutral reference for me, the bass is tight and articulate, the midrange is controlled and balanced, and the highs have tons of sparkle and great extension without sounding hot or too bright. Yes I tend to prefer these with an OTL amp to add a little body, but the fact the A90 can drive them in low gain is really impressive.

Switching to the HE6SE, apart from the V281 I don't think I've had another headphone amp come through that drives them as well as the A90. Medium gain is all that's needed for my listening levels, and they come across beautifully balanced yet with more than enough impact (I'm used to them being used with a speaker amp). The A90 in my personal opinion drives the HE6SE really well.

Moving to IEM's on low gain the A90 has a very black background with no noticeable noise, again the clean nature of the amp really shines through here. I have more than enough control over the volume knob without imbalance at low volumes with sensitive IEM's which is great.

One place where the A90 doesn't necessarily add anything is the soundstaging, overall the sound is tight and controlled but it's not what I would call expansive. It doesn't throw the sound overly wide, but then again it does a great job at just amplifying the source material. There really is only a hint of warmth from the A90, but luckily it steers clear of muddying any of the detail.


Topping, as I have said before, have been on a bit of a roll lately. The D90 is a top performing DAC at a midrange price, the A90 adds tons of amplifying power with a neutral yet slightly warm sound. The D90/A90 stack will suffice for 99% of headphones on the market, even the most hard to drive, and sounds superb doing so. For reviewers like me, it also serves as a superb reference stack and a great benchmark. Like the D90, I cannot recommend the A90 highly enough for the price point.

Sound Perfection Rating: 10/10 (versatile, tons of power that is cleanly delivered)
Hey can you compare the a90 vs v281 ?
Can you tell me how to switch on and off the A90, First the backside where is the power cord, and after the flaceplate to turn on?
And to switch off first turn off the faceplate then after the backside ?
John Massaria
John Massaria
since my comment above ... I actually bought another A90 and kept it for another while and then wound up selling for same reasons- I compared it to my RSA Apache with upgraded 4 SS2590 Sparkos OPAs- and this combo provides me with all the resolution holographic pin point image + stage with gobs of accurate deep bass impact that the A90 for long listening sessions- the A90 is a a top amp for accuracy but a hair boring overall... over all if I had a place for another amp I would keep A90 for dead neutral reference - it surely is just that...



100+ Head-Fier
Yes. I have been using 3 different headphones at the same time. It doesn't change any sound quality.
With me i need to switch power off before i plugin multiple headphones. If I don't usually, not always the sound cuts off from left or right channel on one or both headphones.