Short answer
Both are audio interfaces, both at $299.
The Apogee BOOM reaches 100 dB on 565 of the 567 models here, the Universal Audio Volt 276 on 558.
| Specification | Apogee BOOM | Universal Audio Volt 276 |
|---|---|---|
| Power into 32Ω | 240 mW | 84 mW |
| Power into 150Ω | 51 mW | 28 mW |
| Power into 300Ω | 26 mW | 22 mW |
| Power into 600Ω | 13 mW | 12 mW |
| Output impedance | 0.5 Ω | not published |
| Output noise | not published | not published |
| Price | $299 | $299 |
| Headphones it reaches 100 dB on out of 567 | 565 | 558 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Apogee BOOM | Universal Audio Volt 276 |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Published |
| 600 Ω | Derived | Published |
Both makers publish a power rating. Apogee BOOM publishes at 32 Ω; Universal Audio Volt 276 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 and at 600 Ω only the Universal Audio Volt 276 figure is the maker’s own. On those rows the derived number is the one to doubt first.
7 headphones reach 100 dB on the Apogee BOOM but not on the Universal Audio Volt 276 — Moondrop COSMO, Moondrop PARA 2, Moondrop VENUS, 4 more.
558 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: Apogee BOOM has +32 dB of headroom there against +28 dB. 5 dB is about 2.9 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Apogee BOOM and Universal Audio Volt 276 because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Apogee BOOM headroom | Universal Audio Volt 276 headroom | Apogee BOOM hiss | Universal Audio Volt 276 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +32 dB | +28 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +12 dB | +8 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +21 dB | +18 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +17 dB | +16 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +14 dB | +9 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +10 dB | +10 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +6 dB | +5 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +4 dB | +0 dB | not published | not published |
These two cost the same, $299, so price settles nothing. Out of the 567 models here, the Apogee BOOM drives 7 models to 100 dB — and on the other side there is no such advantage at all.
Only published figures count here; blank axes are counted separately.
Each in full: Apogee BOOM and Universal Audio Volt 276.