Three numbers decide whether a source suits a headphone: how much power it makes at a stated load, how low its output impedance is, and how quiet it is. These 70 sources are the ones whose makers published all three. Every other entry in this database is missing at least one of them, and on those axes this site can only say so.
It is not a ranking and it is not a recommendation. A product gets on this list by filling in its own spec sheet, which costs nothing and which 210 of the 280 products here still do not do. What it buys the reader is the one thing no review provides: the ability to check the claim before buying, and to work out the match for a specific pair of headphones rather than trusting an impression.
The cheapest of them is the JadeAudio JA11 at $20, which is worth sitting with: publishing the full sheet is not a thing only expensive makers can afford.
Sorted by price. What the rest leave out is counted on its own page.
| Source | Price | Type | Output impedance | Output noise |
|---|---|---|---|---|
| JadeAudio JA11 | $20 | USB dongle | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | USB dongle | 0.7 Ω | 1.7 µV |
| FiiO BTR11 | $36 | Bluetooth receiver | 0.5 Ω | 8 µV |
| FiiO BTR13 | $59 | Bluetooth receiver | 0.6 Ω | 1 µV |
| iBasso DC03 Pro | $69 | USB dongle | 0.12 Ω | 0.9 µV |
| FiiO KA13 | $79 | USB dongle | 1.7 Ω | 2.5 µV |
| FiiO KA3 | $79 | USB dongle | 0.5 Ω | 1.7 µV |
| FiiO KA5 | $99 | USB dongle | 0.3 Ω | 1.6 µV |
| JDS Labs Atom+ (2nd gen) | $99 | desktop amplifier | 0.7 Ω | 1.99 µV |
| FiiO BTR15 | $109 | Bluetooth receiver | 1 Ω | 2 µV |
| FiiO BTR5 2021 | $109 | Bluetooth receiver | 1 Ω | 2 µV |
| FiiO KA15 | $109 | USB dongle | 0.8 Ω | 1.7 µV |
| Schiit Magni Unity | $119 | desktop amplifier | 0.1 Ω | 1.59 µV |
| JDS Labs Atom Amp 2 | $129 | desktop amplifier | 0.7 Ω | 1.33 µV |
| FiiO K11 | $143 | desktop DAC/amp | 1.2 Ω | 2.8 µV |
| FiiO KA17 | $149 | USB dongle | 1 Ω | 2 µV |
| Schiit Vali 3 | $149 | desktop amplifier | 0.5 Ω | 2.83 µV |
| Topping L30 II | $149 | desktop amplifier | 0.1 Ω | 0.3 µV |
| SMSL HO100 | $160 | desktop amplifier | <0.1 Ω | 1.3 µV |
| FiiO K11 R2R | $176 | desktop DAC/amp | 1 Ω | 7.2 µV |
The table shows the first 20 of 70. The rest are in the full source list, where every figure is labelled with where it came from.
210 of the 280 sources in this database are not on this list because their makers did not publish all three figures. That is the only test here, and it is not a judgement on how the products sound or measure — it is a statement about what their own documentation contains. Most of the absences are a missing noise figure.
This is not a ranking of sound quality and cannot be. It is ordered by price and selected on numbers that manufacturers printed, and manufacturers do not print anything about how their products sound. Every row links to that product’s own page, where each figure is labelled with the document it came from.
Quietest sources for sensitive in-ears · Lowest published output impedance · Most power into 300 Ω · Ranges printed with a tolerance · Sources nothing cheaper replaces · Sources that drive everything here · Audio interfaces as headphone amplifiers · Sources under $100 · Hardest headphones to drive · Most sensitive in-ears · Quietest desktop sources · What balanced actually gains · Portable players by power · Most power per dollar · High-impedance headphones