Performance and Sound Quality
I was keen to look at the A90 through the lens of the would-be customer who might be considering purchasing the A90 as a ‘do-all’ headphone amplifier, capable of powering all different kinds of headphones. And, there’s no point being able to power something with authority if you ain’t feeling the music – I’m holding the A90 up to very high standards indeed. I’ve been super-impressed by two solid-state headphone amplifiers already this year: the $289 SMSL SP200 THX AAA, and the $199 Schiit Asgard 3. In fact, they both made it to our Recommended Amplifier list. With this in mind, the A90 would need to impress sonically, as well as prove its quality and versatility to earn a ‘nod’ over these two amps which are $210 and $300 cheaper respectively.
It can be a little intangible when trying to impart the nominal differences between the sonic qualities of excellently implemented solid-state amplifiers, but the Topping A90 impresses immediately straight out of the box. In terms of its sonic characteristic, the A90 an utterly transparent, dynamic, and uncoloured presentation. Using my Sennheiser HD600’s which are both honest to a fault in terms of neutrality, as well as highly revealing of an amplifier’s characteristics (both good and bad), the A90 steps right-up and grips your music by the ears. Staging is wide-open, and there isn’t a hint of compression. The bass in Tool’s ‘Invincible’ is felt rather than simply heard – it’s taut, tight, and bloody enjoyable on the HD600’s, which can tend to turn flaccid without proper powering. Danny’s snare and tom hits land with dynamic authority, and Adam’s chugging guitar crunch is vivid and utterly electrifying.
It’s terrific to have the ability to use the A90’s fully balanced configuration, utilising the superior noise-rejection of XLR cables (especially over long cable runs), and to take full advantage of the A90’s power via the balanced headphone outs. However, the A90 also happened to perform perfectly-well with both single-ended inputs via the RCA-in, and via the single-ended headphone-out when tested. The A90 is a terrific-match with its much smaller and more affordable digital cousin, the $129 USD E30 DAC which received a thumbs-up from yours truly earlier this year. If you’re on a firm budget and you have harder-to-drive headphones, or need a dedicated pre-amp in your set-up but still require a capable digital decoder, then the A90/E30 is a superbly-capable $628 stack.
The A90 presents no hint of peak or dip at any frequency – it’s an absolutely achromatic playback experience, yet it isn’t at all devoid of musical enjoyment. Some cheaper solid-state amplifiers can tend to add a sense of ‘glare’ or sterileness to the treble department, but nope – nothing to report here. I had similar feelings when assessing the SMSL SP200 – after a while, you realise you’re simply able to describe the nuances of your headphones themselves. The Topping A90 provides a flawless peek into all the details of a piece of music, good or bad. If it’s there, it will reveal it. If the transducers of your headphones are capable of reproducing it, it’ll do it for them.
Versus my usual desktop amplifier, the Questsyle CMA600i, the A90 was nigh-impossible to tell apart in a back-to-back comparison. Very close listening revealed a shade more treble energy above10kHz in the Topping, which was akin to a mild layer of haze being blown away from the Questyle’s top-end. The CMA600i does have a DAC built-in and is much more substantially built and packaged. But, it was both much more expensive when it was built, and no longer available for sale so it’s not an entirely apples-for-apples comparison. But, the fact that the A90 can play in its ballpark says something about its capabilities.
The Schiit Asgard 3 had a slightly coloured presentation compared to the Topping, with a slight forwardness in the presence region combined with a slightly more congested treble region, without the same sense of ‘air’ as the A90. Now, while the Schiit is considerably more affordable than the A90, it is also only a single-ended unit with the one 6.3mm output. That might be the only connection you need, and if simplicity is your goal, then it may well be for you. However, the A90 is a more versatile all-rounder in terms of its balanced inputs/outputs, and it does present a more vivid, neutral picture than the slightly coloured Asgard 3, which has a more laid-back presentation by comparison. I must note that the Asgard does run quite hot during operation whereas the A90 barely warms up at all, so that might be of consideration when planning a desktop stack/configuration.
Sonically the A90 is line-ball with the SMSL SP200 THX 888, to my ears at least, when volume-matched and played back-to-back. While the SP200 features XLR inputs and a 4-pin headphone output, it’s not a truly balanced topology – these facilities are for convenience only. The SMSL also eschews pre-amplifier functionality to deliver a more bare-bones product. If you’re on a tight budget and $210 difference could be better spent on headphones, than the SP200 will happily give you perfect solid-state headphone performance. But, if you’re likely to upgrade headphones, or like the idea of using it as a preamp, or as part of a fully balanced system than the A90 is certainly worth the upgrade. I think it’s definitely worth it for the upgrade in finish and quality alone – the SP200 feels toy-like when sitting next door to the A90.
Sensitive IEMs: Craft Ears Craft FOUR.
With multiple gain settings and an incredibly-low advertised noise floor, how does the A90 handle sensitive IEMs? Switching the A90’s gain to ‘Low’ and turning the volume down to zero, I plugged in the 10-ohm Polish CIEMs via a 2.5mm to XLR adapter, and didn’t hear so much as a hint of noise. In fact, I had to turn the volume dial up to about 3pm on high-gain before I started to hear the faintest whisper of a noise-floor (with my hand well and truly away from the ‘play’ button…). Back on low gain, I popped-on a CD of Radiohead’s Hail to the Thief from my Nakamichi MB-8 CD-player, and did notice that volume was slightly audible with the volume set to zero. Slowly turning it up, there was a slight patch of volume imbalance before reaching ‘loud enough’ at around 8:30 on the volume pot. Swapping-out the Craft FOUR for the new Final A8000 (keep an eye out for a review around here in the near future!), the less-sensitive flagship universal IEMs from the Japanese manufacturer turned-out to be far more usable on low-gain on the A90, with plenty of usable volume control and less problematic imbalance at the lowest setting.
In short, the A90 is definitely a viable option for IEM users. But, if they are your primary source of sound then you may need to consider either an impedance-raising adapter or perhaps another amplifier altogether if you have more sensitive IEMs.
Head over to page 4 to read more about the A90’s performance.