Short answer
Both are dongles, $179 against $259.
The Shanling UA5 reaches 100 dB on 562 of the 567 models here, the Astell&Kern HC3 on 561.
| Specification | Astell&Kern HC3 | Shanling UA5 |
|---|---|---|
| Power into 32Ω | 125 mW | 137 mW |
| Power into 150Ω | 27 mW | 29 mW |
| Power into 300Ω | 13 mW | 15 mW |
| Power into 600Ω | 6.7 mW | 7.3 mW |
| Output impedance | 2.0 Ω | 0.8 Ω |
| Output noise | not published | 3.5 µV unverified |
| Price | $179 | $259 |
| Headphones it reaches 100 dB on out of 567 | 561 | 562 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | Astell&Kern HC3 | Shanling UA5 |
|---|---|---|
| Socket | no separate rating | 4.4mm |
| Power into 32Ω | — | 211 mW |
| Power into 300Ω | — | 22 mW derived |
| Output impedance | — | 1.6 Ω |
| Output noise | — | not published |
| Headphones it reaches 100 dB on out of 567 | — | 564 |
Only the Shanling UA5 has a separate balanced rating from its maker; through it, it reaches 100 dB on 564 of the 567 models here. The Astell&Kern HC3 may still have a balanced socket — its spec sheet simply gives no figure for one, so there is nothing to put beside it. Derived figures are worked out from the loads the maker did publish.
| Load | Astell&Kern HC3 | Shanling UA5 |
|---|---|---|
| 32 Ω | Upper bound | Published |
| 150 Ω | Upper bound | Derived |
| 300 Ω | Upper bound | Derived |
| 600 Ω | Upper bound | Derived |
These two columns are not the same kind of number, and that matters more than the gap between them. Shanling UA5 publishes a power rating (at 32 Ω); Astell&Kern HC3 publishes no power figure at any load, only a maximum output voltage, so every milliwatt in its column is a ceiling worked out from that voltage.
A ceiling assumes the amplifier holds that voltage into the load, and nothing on Astell&Kern HC3’s own sheet says it does. It is the most flattering reading available, and it is used here only because the alternative is a blank. Where the Astell&Kern HC3 column looks the stronger of the two, treat the difference as unproven rather than measured. 24 of the 280 sources here are in that position, with no published power rating at any load.
1 headphone reaches 100 dB on the Shanling UA5 but not on the Astell&Kern HC3 — Symphonium Zenith.
77 headphones are left alone by the Shanling UA5 under the one-eighth rule but coloured by the Astell&Kern HC3 (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Ocean, 74 more).
561 of the 567 models here reach 100 dB on both.
Headroom is at a 100 dB SPL peak.
Across all eight the two stay within half a decibel of each other, which is a way of saying that on power this pair is one product.
The hiss columns are empty for Astell&Kern HC3 and Shanling UA5 because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Astell&Kern HC3 headroom | Shanling UA5 headroom | Astell&Kern HC3 hiss | Shanling UA5 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +29 dB damping | +30 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +9 dB damping | +10 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +19 dB | +19 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +14 dB | +14 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +11 dB | +11 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +7 dB | +8 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +3 dB | +3 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +1 dB | +2 dB | not published | not published |
The Shanling UA5 costs $80 more than the Astell&Kern HC3. Out of the 567 models here, that difference buys 1 more model driven to 100 dB and 77 more models left alone under the one-eighth rule.
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: Astell&Kern HC3 and Shanling UA5.