Short answer
Both are desktop amplifiers, $129 against $149.
On raw power they are level: each reaches 100 dB on 567 of the 567 non-electrostatic models here.
| Specification | JDS Labs Atom Amp 2 | Schiit Vali 2+ |
|---|---|---|
| Power into 32Ω | 2.6 W | 1.5 W |
| Power into 150Ω | 567 mW | 496 mW |
| Power into 300Ω | 284 mW | 400 mW |
| Power into 600Ω | 143 mW | 200 mW |
| Output impedance | 0.7 Ω | 1.8 Ω |
| Output noise | 1.33 µV | 25 µV unverified |
| Price | $129 | $149 |
| Headphones it reaches 100 dB on out of 567 | 567 | 567 |
| Load | JDS Labs Atom Amp 2 | Schiit Vali 2+ |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Published |
| 600 Ω | Published | Published |
Both makers publish a power rating. JDS Labs Atom Amp 2 publishes at 32 Ω and at 600 Ω; Schiit Vali 2+ 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 300 Ω only the Schiit Vali 2+ figure is the maker’s own. On those rows the derived number is the one to doubt first.
On power they are interchangeable across this whole database: there is no headphone here that one reaches 100 dB on and the other does not.
68 headphones are left alone by the JDS Labs Atom Amp 2 under the one-eighth rule but coloured by the Schiit Vali 2+ (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 65 more).
567 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 HiFiMAN HE400se: JDS Labs Atom Amp 2 has +24 dB of headroom there against +22 dB. 2 dB is about 1.8 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Schiit Vali 2+ because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | JDS Labs Atom Amp 2 headroom | Schiit Vali 2+ headroom | JDS Labs Atom Amp 2 hiss | Schiit Vali 2+ hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +43 dB | +40 dB damping | 17 dB | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +23 dB | +20 dB damping | -3 dB | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +32 dB | +30 dB | -5 dB | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +27 dB | +28 dB | -10 dB | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +24 dB | +22 dB | -11 dB | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +21 dB | +22 dB | -16 dB | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +16 dB | +18 dB | -20 dB | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +15 dB | +12 dB | -22 dB | not published |
The Schiit Vali 2+ costs $20 more than the JDS Labs Atom Amp 2, and on these three axes the money buys nothing: among the 567 models here there is not one that the Schiit Vali 2+ handles and the JDS Labs Atom Amp 2 does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper JDS Labs Atom Amp 2 leaves 68 models alone under the one-eighth rule that the Schiit Vali 2+ does not.
Only published figures count here; blank axes are counted separately.
Each in full: JDS Labs Atom Amp 2 and Schiit Vali 2+.