Short answer
Both are desktop amplifiers, $349 against $289.
The SMSL SH-9 reaches 100 dB on 567 of the 567 models here, the Schiit Valhalla 2 on 561.
| Specification | Schiit Valhalla 2 | SMSL SH-9 |
|---|---|---|
| Power into 32Ω | 115 mW | 3.0 W |
| Power into 150Ω | 426 mW | 741 mW |
| Power into 300Ω | 800 mW | 440 mW |
| Power into 600Ω | 450 mW | 220 mW |
| Output impedance | 14.0 Ω | <0.1 Ω |
| Output noise | not published | 1.5 µV unverified |
| Price | $349 | $289 |
| Headphones it reaches 100 dB on out of 567 | 561 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Schiit Valhalla 2 | SMSL SH-9 |
|---|---|---|
| 32 Ω | Derived | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Published |
| 600 Ω | Published | Published |
Both makers publish a power rating. Schiit Valhalla 2 publishes at 300 Ω and at 600 Ω; SMSL SH-9 at 32 Ω, at 300 Ω and at 600 Ω. The other rows are worked out from those.
So the two columns are not equally firm row by row: at 32 Ω only the SMSL SH-9 figure is the maker’s own. On those rows the derived number is the one to doubt first.
6 headphones reach 100 dB on the SMSL SH-9 but not on the Schiit Valhalla 2 — Moondrop COSMO, Moondrop PARA, Symphonium Crimson, 3 more.
522 headphones are left alone by the SMSL SH-9 under the one-eighth rule but coloured by the Schiit Valhalla 2 (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 519 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 Shure SE846: SMSL SH-9 has +49 dB of headroom there against +29 dB. 20 dB is about 104 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Schiit Valhalla 2 and SMSL SH-9 because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Schiit Valhalla 2 headroom | SMSL SH-9 headroom | Schiit Valhalla 2 hiss | SMSL SH-9 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +29 dB damping | +49 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +9 dB damping | +29 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +25 dB damping | +33 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +30 dB | +29 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +11 dB damping | +27 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +25 dB | +22 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +21 dB | +18 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +6 dB damping | +15 dB | not published | not published |
The Schiit Valhalla 2 costs $60 more than the SMSL SH-9, and on these three axes the money buys nothing: among the 567 models here there is not one that the Schiit Valhalla 2 handles and the SMSL SH-9 does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper SMSL SH-9 drives 6 models to 100 dB and leaves 522 alone under the one-eighth rule that the Schiit Valhalla 2 does not.
Only published figures count here; blank axes are counted separately.
Each in full: Schiit Valhalla 2 and SMSL SH-9.