Aune A17

Sonic Compass does not grade gear. We plot gear and listeners on the same seven axes, so a review tells you where a product sits and you can see how far that is from where you sit.

The Aune A17 is the maker's flagship Class-A headphone amplifier and preamplifier. The unit was sent by Aune for review. I ran it from a Gustard R30 DAC and used my HiFiMAN HE6se V2 for the amp comparisons.

I have not tried the HiFiMAN Susvara on it, so everything below comes from the headphones I own.

Where the A17 sits — Linear, resolving and transparent. It is Class-A, but I did not hear it as smooth or warm the way some Class-A amps are. It adds a sense of realistic weight to notes. Strongest axes are Texture and Detail, Dynamics, and Space.

Bass — Deep, tight and weighty, without bloat or bleed.

Treble — Very detailed, close to analytical, without going anywhere near sibilance. I can hear micro detail, such as the squeak of fingers on frets.

Stage — Instrument separation is so clear it feels holographic, and I can place where a guitar is tracking.

Build, heat and handling — Heavy. It has dual toroidal transformers (a 100 W linear setup), separate power supplies for the digital control circuits and the analogue path, and a fully discrete Class-A circuit with a twin JFET input stage. The Muses R2R volume control gives 99 steps. There are four gain settings and two bias current modes. Outputs are 6.3mm single-ended, 4.4mm balanced and 4-pin XLR balanced, with headphone and preamp outputs usable at the same time. It has a small remote and the display can be turned off. It runs warm, not hot: about 39 C at idle and up to the high 40s or about 50 C on high current. I keep my DAC on a stand about an inch above it.

Current modes — I switched between high and low current many times and could not hear a difference on the A17. On the Aune S17 Pro Evo I could hear one.

Against the Aune S17 Pro Evo (with S18 Evo DAC, my reference stack) — The S17 Pro Evo is no slouch, at 7.5 W into 32 ohms. The A17 has more bass presence, not necessarily deeper but fuller and more noticeable. Staging is not necessarily wider but more 3D and holographic. On Metallica's One the chopper starts at about the same distance, then goes around behind my head on the A17 and more through my head on the S17. The S17 has a slightly smoother treble. The A17 is punchier, and on a violin and bells piece it is cleaner with more resolution. On another track the claps are sharper, the bass deeper and the staging wider. The A17 wins here for me, though the S17 does a good job for the money.

Against the Erzetich Bacillus II+ (my previous top amp) — Bass is similar and both go deep and punch hard. The Bacillus II+ is a little smoother and warmer. Resolution is better on the A17, with more micro detail, particularly up top. Stage width is about the same, but the A17 is more holographic and 3D, and on Metallica's One it puts the sound out behind my head where the Bacillus II+ keeps it nearer the back of my head. The Bacillus II+ drives the HE6se V2 beautifully with no distortion even at maximum volume, but it distorted around the 3:30 to 4:00 position on the Genesis One, while the A17 had none at full volume. Both handle frenetic metal without getting muddy or congested.

Read this against your own profile — I like a transparent, resolving amp with weight and a big stage, and I own hard-to-drive flagship headphones. If that is you and you want one amp for planars, high-impedance dynamics and IEMs, this fits. It is a big, heavy and expensive desktop amp that runs warm.

Honest limits — The unit was supplied by the maker. By ear only, with no measurements, from one DAC. The comparisons are against my own S17 Pro Evo and Bacillus II+ and are level-matched only by ear. I found no cons other than size, weight and price. I made no remark about timing or fatigue, so Timing and Comfort are placed modestly and carry little evidence. The maker's own figures are used for specs.