Short answer
Both are desktop DAC/amps, $319 against $459.
The HiFiMAN EF500 reaches 100 dB on 567 of the 567 models here, the Aune X1s GT on 565.
| Specification | Aune X1s GT | HiFiMAN EF500 |
|---|---|---|
| Power into 32Ω | 320 mW | 1.3 W |
| Power into 150Ω | 68 mW | 282 mW |
| Power into 300Ω | 34 mW | 141 mW |
| Power into 600Ω | 17 mW | 70 mW |
| Output impedance | not published | not published |
| Output noise | not published | not published |
| Price | $319 | $459 |
| Headphones it reaches 100 dB on out of 567 | 565 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | Aune X1s GT | HiFiMAN EF500 |
|---|---|---|
| Socket | 4.4mm | XLR4 |
| Power into 32Ω | 1.2 W | 4.5 W |
| Power into 300Ω | 128 mW derived | 480 mW derived |
| Output impedance | not published | not published |
| Output noise | not published | not published |
| Headphones it reaches 100 dB on out of 567 | 567 | 567 |
Through the balanced sockets the two are level on the same test: each reaches 100 dB on 567 of the 567 models here. Derived figures are worked out from the loads the maker did publish.
| Load | Aune X1s GT | HiFiMAN EF500 |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Derived |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. Aune X1s GT publishes at 32 Ω; HiFiMAN EF500 at 32 Ω. The other rows are worked out from those.
The two publish at the same loads, which is the one case where the rows of this table can be read straight across.
2 headphones reach 100 dB on the HiFiMAN EF500 but not on the Aune X1s GT — Moondrop PARA, Symphonium Titan.
565 of the 567 models here reach 100 dB on both.
Headroom is at a 100 dB SPL peak.
The widest gap on the list is the Sennheiser HD 600: HiFiMAN EF500 has +13 dB of headroom there against +7 dB. 6 dB is about 4.1 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Aune X1s GT and HiFiMAN EF500 because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Aune X1s GT headroom | HiFiMAN EF500 headroom | Aune X1s GT hiss | HiFiMAN EF500 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +34 dB | +40 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +14 dB | +20 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +23 dB | +29 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +18 dB | +24 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +15 dB | +21 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +11 dB | +18 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +7 dB | +13 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +5 dB | +11 dB | not published | not published |
The HiFiMAN EF500 costs $140 more than the Aune X1s GT. Out of the 567 models here, that difference buys 2 more models driven to 100 dB.
Nothing runs the other way: there is no axis here on which the cheaper of the two does better.
Only published figures count here; blank axes are counted separately.
Each in full: Aune X1s GT and HiFiMAN EF500.