Short answer
Both are desktop amplifiers, $350 against $296.
The SMSL H300 reaches 100 dB on 567 of the 567 models here, the Lake People G103-S Mk II on 566.
| Specification | Lake People G103-S Mk II | SMSL H300 |
|---|---|---|
| Power into 32Ω | 1.0 W | 5.0 W |
| Power into 150Ω | 804 mW | 1.1 W |
| Power into 300Ω | 580 mW | 533 mW |
| Power into 600Ω | 340 mW | 267 mW |
| Output impedance | 0.1 Ω | <0.1 Ω |
| Output noise | 6.15 µV | not published |
| Price | $350 | $296 |
| Headphones it reaches 100 dB on out of 567 | 566 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Lake People G103-S Mk II | SMSL H300 |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Derived |
| 600 Ω | Published | Derived |
Both makers publish a power rating. Lake People G103-S Mk II publishes at 32 Ω, at 300 Ω and at 600 Ω; SMSL H300 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 Lake People G103-S Mk II figure is the maker’s own. On those rows the derived number is the one to doubt first.
1 headphone reaches 100 dB on the SMSL H300 but not on the Lake People G103-S Mk II — 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 Campfire Audio Andromeda 2020: SMSL H300 has +32 dB of headroom there against +18 dB. 13 dB is about 20 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for SMSL H300 because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | Lake People G103-S Mk II headroom | SMSL H300 headroom | Lake People G103-S Mk II hiss | SMSL H300 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +38 dB | +52 dB | 30 dB | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +18 dB | +32 dB | 10 dB | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +32 dB | +35 dB | 8 dB | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +30 dB | +30 dB | 4 dB | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +20 dB | +29 dB | 3 dB | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +24 dB | +23 dB | -3 dB | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +19 dB | +19 dB | -7 dB | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +14 dB | +17 dB | -9 dB | not published |
The Lake People G103-S Mk II costs $54 more than the SMSL H300, and on these three axes the money buys nothing: among the 567 models here there is not one that the Lake People G103-S Mk II handles and the SMSL H300 does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper SMSL H300 drives one model to 100 dB that the Lake People G103-S Mk II does not.
Only published figures count here; blank axes are counted separately.
Each in full: Lake People G103-S Mk II and SMSL H300.