On power: 50 of the 51 USB dongles here reach 100 dB SPL on the Abyss AB-1266 Phi TC. It needs 16 mW at its 50Ω, and 1 of them do not get there.
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 1 that fall short are Apple USB-C dongle (EU). The closest of them, the Apple USB-C dongle (EU), delivers 9.9 mW into 50Ω against the 16 mW needed — 2.0 dB short.
The cheapest one that does reach it is the Apple USB-C dongle (US) at $9, which delivers 20 mW into 50Ω — 1 dB of headroom over the 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 0.50 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 Abyss AB-1266 Phi TC wants a source below 6.25Ω. Of the 18 USB dongles here that publish an output impedance, 18 are under it and 0 are not.
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 88.0 dB/mW and 50Ω, the Abyss AB-1266 Phi TC turns one microvolt of source noise into about -19 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 50 Ω | Headroom | Output impedance | Hiss in these |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 19 mW | 0.8 dB | 0.5 Ω | -14 dB SPL |
| FiiO KA11 | $29 | 128 mW | 9.1 dB | 0.7 Ω | -14 dB SPL |
| iBasso DC03 Pro | $69 | 63 mW | 6.0 dB | 0.12 Ω | -20 dB SPL |
8 of the 51 USB dongles here publish all three figures. 8 of those clear all three for the Abyss AB-1266 Phi TC, and the cheapest is the JadeAudio JA11 at $20.
It delivers 19 mW into 50 Ω where this headphone needs 16 mW for 100 dB — 0.8 dB of headroom — its output impedance of 0.5 Ω sits under the one-eighth ceiling of 6.25 Ω, and its 1.7 µV of noise leaves the hiss 34 dB under the 20 dB SPL threshold this site uses.
Cheapest that satisfies three published numbers is not the same as best, and the sources left out of this count are left out for want of a published figure, not for failing one. How often that happens is its own page.
| Source | Price | Into 50Ω | Output impedance | Hiss in these | Power verdict |
|---|---|---|---|---|---|
| Tempotec Sonata BHD Pro | $60 | 179 mW | not published | not published | Comfortable |
| ddHiFi TC44 Pro E2 | $99 | 160 mW | not published | not published | Comfortable |
| Tanchjim LUNA | $140 | 191 mW | not published | -17 dB SPL | Comfortable |
| Moondrop Moonriver 2 Ti | $190 | 187 mW | not published | -15 dB SPL | Comfortable |
| Qudelix T71 | $229 | 320 mW | not published | not published | Comfortable |
| Questyle M15 | $250 | 211 mW | not published | not published | Comfortable |
| Generic CX31993 dongles | $12 | 41 mW | not published | not published | Enough |
| FiiO KA11 | $29 | 128 mW | 0.7 Ω | -14 dB SPL | Enough |
| Tanchjim Stargate II | $40 | 48 mW | not published | not published | Enough |
| ddHiFi TC35AL | $46 | 134 mW | not published | not published | Enough |
| ddHiFi TC35Air | $46 | 134 mW | not published | not published | Enough |
| Hidizs SD2 | $50 | 45 mW | not published | not published | Enough |
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 Abyss AB-1266 Phi TC on other categories: portable players · desktop amplifiers · desktop DAC/amps · audio interfaces.
The Abyss AB-1266 Phi TC page has every source in the database against this headphone, and the matcher takes your own numbers.