Audio interfaces are the most common headphone amplifier in the world, because anyone who records anything already owns one. They are also the category where output impedance goes wrong most often: a headphone output designed around 250 Ω studio monitors can sit at 50 Ω, which is fine for what it was built for and wrong for a multi-driver in-ear.
This lists every interface in the database by price, with what it delivers into 32 Ω and the output impedance its maker published — where one was published at all.
| Interface | Price | Into 32 Ω | Output impedance |
|---|---|---|---|
| Zoom AMS-22 | $100 | 20 mW | 10 Ω |
| Steinberg IXO22 | $119 | 32 mW | not published |
| Audient EVO 4 | $129 | 22 mW | 50 Ω |
| IK Multimedia AXE I/O ONE | $130 | 26 mW | <0.1 Ω |
| Focusrite Scarlett Solo 4th gen | $139 | 31 mW | 50 Ω |
| Arturia MiniFuse 1 | $149 | 139 mW | 10 Ω |
| Arturia MiniFuse 2 | $149 | 139 mW | 10 Ω |
| PreSonus Studio 24c | $149 | 27 mW | not published |
| Universal Audio Volt 1 | $149 | 84 mW | not published |
| Zoom AMS-24 | $150 | 30 mW | 10 Ω |
| Steinberg UR24C | $194 | 80 mW | not published |
| Audient iD4 MkII | $199 | 112 mW | not published |
| Focusrite Scarlett 2i2 4th gen | $199 | 31 mW | 50 Ω |
| PreSonus Quantum ES 2 | $199 | 106 mW | not published |
| Steinberg UR22C | $199 | 12 mW | not published |
The table shows the first 15 of 65. The rest are in the full source list, where every figure is labelled with where it came from.
215 of the 280 sources in this database are not on this list because they are not audio interfaces. This one is a category, not a ranking threshold.
This is not a ranking of sound quality and cannot be. It sorts one number 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 · Sources that drive everything here · 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