Short answer
Both are desktop amplifiers, $370 against $349.
The Geshelli Archel 3S Pro reaches 100 dB on 567 of the 567 models here, the Schiit Valhalla 2 on 561.
| Specification | Geshelli Archel 3S Pro | Schiit Valhalla 2 |
|---|---|---|
| Power into 32Ω | 1.0 W | 115 mW |
| Power into 150Ω | 213 mW | 426 mW |
| Power into 300Ω | 107 mW | 800 mW |
| Power into 600Ω | 53 mW | 450 mW |
| Output impedance | not published | 14.0 Ω |
| Output noise | not published | not published |
| Price | $370 | $349 |
| Headphones it reaches 100 dB on out of 567 | 567 | 561 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Geshelli Archel 3S Pro | Schiit Valhalla 2 |
|---|---|---|
| 32 Ω | Derived | Derived |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Published |
| 600 Ω | Derived | Published |
Only one of these two columns starts from a power rating. Schiit Valhalla 2 publishes one at 300 Ω and at 600 Ω; Geshelli Archel 3S Pro publishes none at any of these four loads, so its column is worked out from power it published at other loads. Both are arithmetic on a maker’s own figures rather than guesses, and the method used for the Geshelli Archel 3S Pro understates rather than flatters — but at 300 Ω and at 600 Ω are the only loads here at which its maker can be held to a figure.
6 headphones reach 100 dB on the Geshelli Archel 3S Pro but not on the Schiit Valhalla 2 — Moondrop COSMO, Moondrop PARA, Symphonium Crimson, 3 more.
561 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 Campfire Audio Andromeda 2020: Geshelli Archel 3S Pro has +25 dB of headroom there against +9 dB. 15 dB is about 35 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Geshelli Archel 3S Pro and Schiit Valhalla 2 because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Geshelli Archel 3S Pro headroom | Schiit Valhalla 2 headroom | Geshelli Archel 3S Pro hiss | Schiit Valhalla 2 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +45 dB | +29 dB damping | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +25 dB | +9 dB damping | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +28 dB | +25 dB damping | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +23 dB | +30 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +22 dB | +11 dB damping | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +16 dB | +25 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +12 dB | +21 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +10 dB | +6 dB damping | not published | not published |
The Geshelli Archel 3S Pro costs $21 more than the Schiit Valhalla 2. Out of the 567 models here, that difference buys 6 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: Geshelli Archel 3S Pro and Schiit Valhalla 2.