Topping A90 Review: sonic transparency and power to spare

Topping produces a wide range of devices for hi-fi enthusiasts, some of which—such as the A90 under review here, or the D90SE, a DAC often paired with the A90 in mid-to-high-end systems—are extremely popular among enthusiasts thanks to their excellent value for money. The A90 is a headphone amplifier that also functions as a preamplifier, a switchable option at any time via a toggle located on the front panel, which also controls the power on/off of the unit.

This versatility represents an interesting opportunity, as it makes the A90 suitable both as a headphone amplifier and as a preamplifier in a speaker system, by connecting the A90 to a power amplifier.

On the front panel, the amp also features a toggle for input selection (RCA or XLR), a gain selector (low, medium, high), as well as an XLR headphone output, a balanced 4.4 mm Pentaconn output, and the traditional 6.35 mm jack output, along with a very well-made volume knob that allows smooth and gradual volume adjustments.

On the rear, the Topping A90 features the power input (cable included in the package), a power switch (also present on the front via the toggle), and input/output connections: two XLR inputs and two XLR outputs, as well as RCA inputs and outputs.

The amplifier comes in an elegant black box with foam cutouts inside and includes, in addition to the amplifier itself, a 6.35 mm adapter, the power cable, the user manual, and a warranty leaflet that also serves as a catalog of the company’s other devices.

Functions, Features and Technology

Before moving on to the actual review of the Topping A90, let’s take a look at the declared technical specifications:

• Noise: <0.2uVrms
• THD+N: <0.00006%
• Dynamic range: 145 decibels
• Preamplifier function
• Output impedance: <0.1 ohm
• Maximum output power: 7600mWx2
• Dimensions: 22cm x 16cm x 4.5cm
• Weight: 2.5 kg

The A90 features a technology called NFCA (Nested Feedback Composite Amplifier), modules capable of achieving outstanding laboratory results, with extremely low noise levels and a remarkable dynamic range. Build quality is very satisfying: dimensions are relatively compact, the device is fully metal, very solid and well-finished, with a minimal yet appealing design. The front panel (black or silver depending on the variant) is enhanced by a colored LED (green or orange depending on whether it is set to headphone amplifier (HPA) or preamplifier (PRE)).

Power

It’s no coincidence that the full name of the A90 is “A90 Ultra-High Performance Headphone Amplifier”: this Topping device has power to spare and can handle virtually any headphone. We tested it with various models, including the latest HE1000 v3 from Hifiman, and we can confidently say that the A90 drives even the most power-hungry headphones with ease. You won’t hear any buzz or background noise, even at very high and potentially dangerous volume levels.

Sound Performance

The A90 does not impose a warm coloration or particular effects on recordings: the device works to reproduce tracks in a faithful, clear, clean, and natural way. The overall impression is that of a sound signature leaning toward neutrality and even transparency, capable of pushing good headphones toward an even more detailed, clean, defined, and energetic reproduction, always characterized by strong dynamics.

We appreciated the amplifier’s performance with a balanced XLR cable as well as with a traditional unbalanced one, and we recommend opting for the former whenever possible. It goes without saying that with an amp so focused on transparency, high-quality recordings will shine, while flaws in poor recordings will also become evident. Clarity, detail, and naturalness make the A90 appealing to most enthusiasts and very versatile in pairings; on the other hand, those seeking a warmer or more colored sound signature are likely already considering high-end gear, often tube-based rather than solid-state.

Paired with headphones also oriented toward a neutral/natural and highly detailed sound like the Arya v3, the A90 brings out all its qualities, maximizing definition, cleanliness, and clarity. The A90 does not fear pairing with high or even very high-end headphones and DACs: it performs a “silent” job, adapting and enhancing the other components in the system. Added to this is the already mentioned power, allowing the Topping amp to drive virtually anything without issue.

Pairings

As many enthusiasts know, the most recommended pairing is with the Topping D90SE DAC, a powerhouse DAC with excellent performance and a price of around €900. The A90 and D90SE form a duo, costing around €1500, capable of delivering outstanding performance for headphone enthusiasts (as well as those using them in speaker systems). To achieve significantly better performance, one must look into the high-end market at much higher prices.

That said, the A90 can still be paired with your preferred DAC without issues, naturally achieving better results with mid-range or higher DACs. Even when connected to a budget DAC such as the iFi Zen DAC v3, the jump in quality from a modest amplifier (say under €300) to the A90 is significant. Therefore, the A90 can also be purchased as a first step in upgrading a headphone system and appreciated even with non-top-tier DACs, perhaps in anticipation of a future upgrade.

Conclusions

The A90 offers a value for money that leads us to strongly recommend it to a wide range of users: first of all, to those looking for a mid-to-high-end headphone amplifier at a barely mid-range price; and also to those who want an amp capable of driving any headphones, with the added benefit of a preamplifier function that can be very useful in speaker systems.

Technical measurements from independent reviewers as well as the manufacturer (see tests from Audio Science Review) confirm the excellent work done in terms of noise (or lack thereof), dynamic range, and total harmonic distortion. Our tests with DACs and headphones across various price ranges (€250 to €2400) highlighted the excellent and thoughtful work by the Chinese company, which managed to create a high-performance product at a highly competitive price, with features that meet the diverse needs of audiophiles: if your budget is around €500, it will be hard to find something better than the A90.