Short answer
Both are audio interfaces, $149 against $100.
The Universal Audio Volt 1 reaches 100 dB on 558 of the 567 models here, the Zoom AMS-22 on 538.
| Specification | Universal Audio Volt 1 | Zoom AMS-22 |
|---|---|---|
| Power into 32Ω | 84 mW | 20 mW |
| Power into 150Ω | 28 mW | 6.5 mW |
| Power into 300Ω | 22 mW | 3.4 mW |
| Power into 600Ω | 12 mW | 1.8 mW |
| Output impedance | not published | 10 Ω |
| Output noise | not published | not published |
| Price | $149 | $100 |
| Headphones it reaches 100 dB on out of 567 | 558 | 538 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Universal Audio Volt 1 | Zoom AMS-22 |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Derived |
| 600 Ω | Published | Derived |
Both makers publish a power rating. Universal Audio Volt 1 publishes at 32 Ω, at 300 Ω and at 600 Ω; Zoom AMS-22 at 32 Ω. The other rows are worked out from those.
So the two columns are not equally firm row by row: at 300 Ω and at 600 Ω only the Universal Audio Volt 1 figure is the maker’s own. On those rows the derived number is the one to doubt first.
20 headphones reach 100 dB on the Universal Audio Volt 1 but not on the Zoom AMS-22 — Abyss AB-1266 Phi TC, Audeze LCD-5, Beyerdynamic DT 880 Edition (600Ω), 17 more.
538 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 Audio-Technica ATH-R70X: Universal Audio Volt 1 has +10 dB of headroom there against +2 dB. 8 dB is about 6.6 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Universal Audio Volt 1 and Zoom AMS-22 because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Universal Audio Volt 1 headroom | Zoom AMS-22 headroom | Universal Audio Volt 1 hiss | Zoom AMS-22 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +28 dB | +22 dB damping | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +8 dB | +2 dB damping | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +18 dB | +11 dB damping | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +16 dB | +8 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +9 dB | +3 dB damping | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +10 dB | +2 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +5 dB | -3 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +0 dB | -6 dB damping | not published | not published |
The Universal Audio Volt 1 costs $49 more than the Zoom AMS-22. Out of the 567 models here, that difference buys 20 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: Universal Audio Volt 1 and Zoom AMS-22.