Both are desktop amplifiers, $130 against $119. 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?
The Schiit Magni Unity reaches 100 dB on 567 of the 567 models here, the ART HeadAmp 4 Pro on 561.
| Specification | ART HeadAmp 4 Pro | Schiit Magni Unity |
|---|---|---|
| Power into 32Ω | 98 mW | 2.5 W |
| Power into 150Ω | 67 mW | 622 mW |
| Power into 300Ω | 33 mW | 415 mW |
| Power into 600Ω | 17 mW | 220 mW |
| Output impedance | 47.0 Ω | 0.1 Ω |
| Output noise | not published | not published |
| Price | $130 | $119 |
| Headphones it reaches 100 dB on out of 567 | 561 | 567 |
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.
6 headphones reach 100 dB on the Schiit Magni Unity but not on the ART HeadAmp 4 Pro — Moondrop COSMO, Moondrop PARA, Symphonium Crimson, 3 more.
561 headphones are left alone by the Schiit Magni Unity under the one-eighth rule but coloured by the ART HeadAmp 4 Pro (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 558 more).
561 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.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: ART HeadAmp 4 Pro and Schiit Magni Unity. Or put either against your own headphones in the source comparison tool.