Short answer
Both are desktop amplifiers, $375 against $399.
The SMSL HO200 reaches 100 dB on 567 of the 567 models here, the Bottlehead Crack (OTL kit) on 565.
| Specification | Bottlehead Crack (OTL kit) | SMSL HO200 |
|---|---|---|
| Power into 32Ω | 271 mW | 3.0 W |
| Power into 150Ω | 403 mW | 640 mW |
| Power into 300Ω | 333 mW | 320 mW |
| Power into 600Ω | 227 mW | 160 mW |
| Output impedance | 120.0 Ω | <0.1 Ω |
| Output noise | not published | 1.0 µV |
| Price | $375 | $399 |
| Headphones it reaches 100 dB on out of 567 | 565 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Bottlehead Crack (OTL kit) | SMSL HO200 |
|---|---|---|
| 32 Ω | Derived | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Derived |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. Bottlehead Crack (OTL kit) publishes at 300 Ω; SMSL HO200 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 only the Bottlehead Crack (OTL kit) figure is the maker’s own and at 32 Ω only the SMSL HO200 figure is the maker’s own. On those rows the derived number is the one to doubt first.
2 headphones reach 100 dB on the SMSL HO200 but not on the Bottlehead Crack (OTL kit) — Moondrop PARA, Symphonium Titan.
567 headphones are left alone by the SMSL HO200 under the one-eighth rule but coloured by the Bottlehead Crack (OTL kit) (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 564 more).
565 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: SMSL HO200 has +49 dB of headroom there against +33 dB. 16 dB is about 44 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Bottlehead Crack (OTL kit) because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | Bottlehead Crack (OTL kit) headroom | SMSL HO200 headroom | Bottlehead Crack (OTL kit) hiss | SMSL HO200 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +33 dB damping | +49 dB | not published | 14 dB |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +13 dB damping | +29 dB | not published | -6 dB |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +26 dB damping | +32 dB | not published | -7 dB |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +27 dB damping | +28 dB | not published | -12 dB |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +14 dB damping | +27 dB | not published | -13 dB |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +22 dB damping | +21 dB | not published | -19 dB |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +17 dB damping | +17 dB | not published | -23 dB |
| HiFiMAN Susvara | 60 Ω | 50 mW | +7 dB damping | +15 dB | not published | -25 dB |
The SMSL HO200 costs $24 more than the Bottlehead Crack (OTL kit). Out of the 567 models here, that difference buys 2 more models driven to 100 dB and 567 more models left alone under the one-eighth rule.
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: Bottlehead Crack (OTL kit) and SMSL HO200.