On power, yes — all of them. Every one of the 51 USB dongles in this database reaches 100 dB SPL on the 64 Audio U12t, which needs 0.16 mW at its 12.6Ω.
Power is one of three questions and the one that goes wrong least often. The other two — whether the source’s output impedance leaves the frequency response alone, and whether you will hear its noise floor — are answered further down, separately, because a source can pass one and fail another.
The cheapest one that does reach it is the Apple USB-C dongle (EU) at $9, which delivers 5.9 mW into 12.6Ω — 16 dB of headroom over the 0.16 mW this headphone needs for 100 dB SPL.
100 dB SPL is a peak level, not a listening level. If you listen at 85 dB the same headphone needs 0.01 mW, which is 15 dB less, and the answer above changes for most of the category. The model page has the full ladder.
Under the one-eighth rule the 64 Audio U12t wants a source below 1.57Ω. Of the 18 USB dongles here that publish an output impedance, 16 are under it and 2 are not.
The furthest over is the Astell&Kern HC3 at 2Ω, which is 1× the ceiling. Above that threshold the source stops being a volume control and starts being part of the frequency response. The simulator shows what that looks like.
The other 33 publish nothing at all on this, so they are not on either side of that count. This site leaves them blank rather than assuming a figure.
Hiss depends on the source’s own noise floor and on how sensitive the headphone is. At 108.0 dB/mW and 12.6Ω, the 64 Audio U12t turns one microvolt of source noise into about 7 dB SPL — and the threshold where that stops being noticeable in a quiet room is around 20 dB SPL.
Of the 16 USB dongles here that publish a noise figure, 16 stay below that threshold with this headphone and 0 cross it.
The remaining 35 publish no noise figure, so they cannot be placed on either side.
| Source | Price | Into 12.6Ω | Output impedance | Hiss in these | Power verdict |
|---|---|---|---|---|---|
| Apple USB-C dongle (EU) | $9 | 5.9 mW | not published | not published | Comfortable |
| Apple USB-C dongle (US) | $9 | 12 mW | not published | not published | Comfortable |
| Generic CX31993 dongles | $12 | 24 mW | not published | not published | Comfortable |
| JadeAudio JA11 | $20 | 12 mW | 0.5 Ω | 12 dB SPL | Comfortable |
| FiiO SnowSky Tiny A | $22 | 35 mW | 0.5 Ω | not published | Comfortable |
| FiiO SnowSky Tiny B | $22 | 54 mW | 1 Ω | not published | Comfortable |
| Kiwi Ears Allegro Mini | $24 | 12 mW | not published | 17 dB SPL | Comfortable |
| FiiO KA11 | $29 | 193 mW | 0.7 Ω | 12 dB SPL | Comfortable |
| Tanchjim Stargate II | $40 | 65 mW | not published | not published | Comfortable |
| ddHiFi TC35AL | $46 | 83 mW | not published | not published | Comfortable |
| ddHiFi TC35Air | $46 | 83 mW | not published | not published | Comfortable |
| Hidizs SD2 | $50 | 28 mW | not published | not published | Comfortable |
Sorted by how many of the three questions the source answers well, then by price. A blank in a column is a blank in the manufacturer’s own documentation, not a zero.
The 64 Audio U12t on other categories: Bluetooth receivers · portable players · desktop amplifiers · desktop DAC/amps · audio interfaces.
The 64 Audio U12t page has every source in the database against this headphone, and the matcher takes your own numbers.