JDS Labs Atom Amp 2 vs Schiit Vali 2+

Both are desktop amplifiers, $129 against $149. This page puts them side by side on the only three things a maker can be held to — power, output impedance and noise — and then asks the question that actually matters: which headphones do they treat differently?

On raw power they are level: each reaches 100 dB on 567 of the 567 non-electrostatic models here.

A figure marked not published is missing from the maker’s own material, which is not the same as being good or bad. Where one of these two publishes a number and the other does not, the comparison on that axis cannot be made at all — and saying so is more useful than guessing.

Both makers publish a power rating, which is less common than the table above makes it look: of the 280 sources here, 209 publish a figure at at least one load and only 2 publish one at all four. 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. Every other row is worked out from those — between two published loads, or beyond them holding voltage constant, which understates rather than flatters.

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.

What each of these labels means, and why a derived figure is still worth printing, is set out in how this data was built.

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. That is a power count and nothing more; whether either source suits a given headphone also depends on the two lines above.

The counts above say how many models the two treat differently. This says by how much. The same 8 headphones appear on every page of this kind, ordered from the easiest to drive to the hardest, so a row can be read across pages as well as across columns. 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. That is a gap in the specification, not a quiet amplifier, and it is left blank here rather than filled with a plausible number.

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.

Everything in this paragraph counts only figures the two makers published. An advantage on an axis one of them leaves blank cannot be counted, and is not counted — how often that happens is its own page.

Each has a page of its own with every power figure traced to what the maker published and a full headphone list: JDS Labs Atom Amp 2 and Schiit Vali 2+. Or put either against your own headphones in the source comparison tool.