Short answer
Both are dongles, $59 against $60.
The Tempotec Sonata BHD Pro reaches 100 dB on 565 of the 567 models here, the iFi GO link on 556.
| Specification | iFi GO link | Tempotec Sonata BHD Pro |
|---|---|---|
| Power into 32Ω | 70 mW | 280 mW |
| Power into 150Ω | 20 mW | 60 mW |
| Power into 300Ω | 14 mW | 30 mW |
| Power into 600Ω | 7.0 mW | 15 mW |
| Output impedance | 0.4 Ω | 0.6 Ω unverified |
| Output noise | not published | 4 µV unverified |
| Price | $59 | $60 |
| Headphones it reaches 100 dB on out of 567 | 556 | 565 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | iFi GO link | Tempotec Sonata BHD Pro |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Derived |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. iFi GO link publishes at 32 Ω and at 300 Ω; Tempotec Sonata BHD Pro 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 iFi GO link figure is the maker’s own. On those rows the derived number is the one to doubt first.
9 headphones reach 100 dB on the Tempotec Sonata BHD Pro but not on the iFi GO link — HiFiMAN Susvara, Moondrop COSMO, Moondrop PARA 2, 6 more.
556 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: Tempotec Sonata BHD Pro has +13 dB of headroom there against +7 dB. 6 dB is about 4 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for iFi GO link and Tempotec Sonata BHD Pro because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | iFi GO link headroom | Tempotec Sonata BHD Pro headroom | iFi GO link hiss | Tempotec Sonata BHD Pro hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +27 dB | +33 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +7 dB | +13 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +16 dB | +22 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +14 dB | +18 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +8 dB | +14 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +8 dB | +11 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +3 dB | +7 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | -1 dB | +5 dB | not published | not published |
The Tempotec Sonata BHD Pro costs $1 more than the iFi GO link. Out of the 567 models here, that difference buys 9 more models 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: iFi GO link and Tempotec Sonata BHD Pro.