Short answer
Both are desktop amplifiers, $1795 against $1600.
The Headamp GS-X Mini reaches 100 dB on 567 of the 567 models here, the SPL Phonitor se on 566.
| Specification | Headamp GS-X Mini | SPL Phonitor se |
|---|---|---|
| Power into 32Ω | 1.3 W | 1.0 W |
| Power into 150Ω | 333 mW | 3.1 W |
| Power into 300Ω | 167 mW | 4.2 W |
| Power into 600Ω | 83 mW | 2.1 W |
| Output impedance | 0.05 Ω unverified | 0.18 Ω |
| Output noise | 1.5 µV unverified | 5.48 µV |
| Price | $1795 | $1600 |
| Headphones it reaches 100 dB on out of 567 | 567 | 566 |
| Balanced | Headamp GS-X Mini | SPL Phonitor se |
|---|---|---|
| Socket | XLR4 | no separate rating |
| Power into 32Ω | 5.1 W derived | — |
| Power into 300Ω | 667 mW derived | — |
| Output impedance | not published | — |
| Output noise | not published | — |
| Headphones it reaches 100 dB on out of 567 | 567 | — |
Only the Headamp GS-X Mini has a separate balanced rating from its maker; through it, it reaches 100 dB on 567 of the 567 models here. The SPL Phonitor se may still have a balanced socket — its spec sheet simply gives no figure for one, so there is nothing to put beside it. Derived figures are worked out from the loads the maker did publish.
| Load | Headamp GS-X Mini | SPL Phonitor se |
|---|---|---|
| 32 Ω | Derived | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Derived |
| 600 Ω | Derived | Derived |
Only one of these two columns starts from a power rating. SPL Phonitor se publishes one at 32 Ω; Headamp GS-X Mini publishes none at any of these four loads, so its column is worked out from power it published at other loads. Both are arithmetic on a maker’s own figures rather than guesses, and the method used for the Headamp GS-X Mini understates rather than flatters — but at 32 Ω is the only load here at which its maker can be held to a figure.
1 headphone reaches 100 dB on the Headamp GS-X Mini but not on the SPL Phonitor se — Symphonium Titan.
566 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: SPL Phonitor se has +32 dB of headroom there against +18 dB. 14 dB is about 25 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Headamp GS-X Mini because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | Headamp GS-X Mini headroom | SPL Phonitor se headroom | Headamp GS-X Mini hiss | SPL Phonitor se hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +41 dB | +38 dB | not published | 29 dB |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +21 dB | +18 dB | not published | 9 dB |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +30 dB | +33 dB | not published | 7 dB |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +25 dB | +39 dB | not published | 3 dB |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +23 dB | +20 dB | not published | 2 dB |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +18 dB | +32 dB | not published | -4 dB |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +14 dB | +28 dB | not published | -8 dB |
| HiFiMAN Susvara | 60 Ω | 50 mW | +12 dB | +15 dB | not published | -10 dB |
The Headamp GS-X Mini costs $195 more than the SPL Phonitor se. Out of the 567 models here, that difference buys 1 more model 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: Headamp GS-X Mini and SPL Phonitor se.