Short answer
Both are desktop amplifiers, $499 against $600.
On raw power they are level: each reaches 100 dB on 566 of the 567 non-electrostatic models here.
| Specification | Schiit Valhalla 3 | Soncoz SGA1 |
|---|---|---|
| Power into 32Ω | 750 mW | 407 mW |
| Power into 150Ω | 286 mW | 207 mW |
| Power into 300Ω | 250 mW | 210 mW |
| Power into 600Ω | 125 mW | 105 mW |
| Output impedance | 25 Ω | 0.1 Ω |
| Output noise | 6.32 µV | 1.8 µV |
| Price | $499 | $600 |
| Headphones it reaches 100 dB on out of 567 | 566 | 566 |
| Balanced | Schiit Valhalla 3 | Soncoz SGA1 |
|---|---|---|
| Socket | no separate rating | 4-Pin XLR + 4.4mm |
| Power into 32Ω | — | 407 mW derived |
| Power into 300Ω | — | 840 mW |
| Output impedance | — | 0.05 Ω |
| Output noise | — | 3.6 µV |
| Headphones it reaches 100 dB on out of 567 | — | 566 |
Only the Soncoz SGA1 has a separate balanced rating from its maker; through it, it reaches 100 dB on 566 of the 567 models here. The Schiit Valhalla 3 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 | Schiit Valhalla 3 | Soncoz SGA1 |
|---|---|---|
| 32 Ω | Published | Derived |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Published |
| 600 Ω | Derived | Published |
Both makers publish a power rating. Schiit Valhalla 3 publishes at 32 Ω and at 300 Ω; Soncoz SGA1 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 32 Ω only the Schiit Valhalla 3 figure is the maker’s own and at 600 Ω only the Soncoz SGA1 figure is the maker’s own. On those rows the derived number is the one to doubt first.
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.
535 headphones are left alone by the Soncoz SGA1 under the one-eighth rule but coloured by the Schiit Valhalla 3 (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 532 more).
100 headphones stay below the audible-hiss threshold on the Soncoz SGA1 but cross it on the Schiit Valhalla 3 (64 Audio Fourte, 64 Audio Nio, 64 Audio U12t, 97 more).
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 Shure SE846: Schiit Valhalla 3 has +37 dB of headroom there against +35 dB. 3 dB is about 1.8 times the power, which matters for peaks rather than for how loud the music sits.
Hiss below about 20 dB SPL is inaudible in a quiet room.
| Headphone | Impedance | Needs | Schiit Valhalla 3 headroom | Soncoz SGA1 headroom | Schiit Valhalla 3 hiss | Soncoz SGA1 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +37 dB damping | +35 dB | 30 dB | 20 dB |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +17 dB damping | +15 dB | 10 dB | -0 dB |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +27 dB damping | +25 dB | 9 dB | -2 dB |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +26 dB | +25 dB | 4 dB | -7 dB |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +19 dB damping | +16 dB | 3 dB | -8 dB |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +20 dB | +19 dB | -3 dB | -14 dB |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +16 dB | +15 dB | -7 dB | -18 dB |
| HiFiMAN Susvara | 60 Ω | 50 mW | +10 dB damping | +8 dB | -9 dB | -20 dB |
The Soncoz SGA1 costs $101 more than the Schiit Valhalla 3. Out of the 567 models here, that difference buys 535 more models left alone under the one-eighth rule and 100 more models kept below the audible-hiss threshold.
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: Schiit Valhalla 3 and Soncoz SGA1.