Both are dongles, $60 against $60. This page puts them side by side on the only three things a maker can be held to — power, output impedance and noise — and then asks the question that actually matters: which headphones do they treat differently?
The Tempotec Sonata BHD Pro reaches 100 dB on 565 of the 567 models here, the Kiwi Ears Allegro Pro on 554.
| Specification | Kiwi Ears Allegro Pro | Tempotec Sonata BHD Pro |
|---|---|---|
| Power into 32Ω | 68 mW | 280 mW |
| Power into 150Ω | 15 mW | 60 mW |
| Power into 300Ω | 7.3 mW | 30 mW |
| Power into 600Ω | 3.6 mW | 15 mW |
| Output impedance | not published | 0.6 Ω unverified |
| Output noise | not published | 4 µV unverified |
| Price | $60 | $60 |
| Headphones it reaches 100 dB on out of 567 | 554 | 565 |
A figure marked not published is missing from the maker’s own material, which is not the same as being good or bad. Where one of these two publishes a number and the other does not, the comparison on that axis cannot be made at all — and saying so is more useful than guessing.
11 headphones reach 100 dB on the Tempotec Sonata BHD Pro but not on the Kiwi Ears Allegro Pro — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 8 more.
554 of the 567 models here reach 100 dB on both. That is a power count and nothing more; whether either source suits a given headphone also depends on the two lines above.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: Kiwi Ears Allegro Pro and Tempotec Sonata BHD Pro. Or put either against your own headphones in the source comparison tool.