Short answer
Both are dongles, $79 against $59.
The iFi GO link reaches 100 dB on 556 of the 567 models here, the FiiO KA13 on 555.
| Specification | FiiO KA13 | iFi GO link |
|---|---|---|
| Power into 32Ω | 50 mW | 70 mW |
| Power into 150Ω | 10 mW | 20 mW |
| Power into 300Ω | 5.0 mW | 14 mW |
| Power into 600Ω | 2.5 mW | 7.0 mW |
| Output impedance | 1.7 Ω | 0.4 Ω |
| Output noise | 2.5 µV | not published |
| Price | $79 | $59 |
| Headphones it reaches 100 dB on out of 567 | 555 | 556 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | FiiO KA13 | iFi GO link |
|---|---|---|
| Socket | 4.4mm | no separate rating |
| Power into 32Ω | 260 mW | — |
| Power into 300Ω | 20 mW | — |
| Output impedance | 1.8 Ω | — |
| Output noise | 4.6 µV | — |
| Headphones it reaches 100 dB on out of 567 | 565 | — |
Only the FiiO KA13 has a separate balanced rating from its maker; through it, it reaches 100 dB on 565 of the 567 models here. The iFi GO link may still have a balanced socket — its spec sheet simply gives no figure for one, so there is nothing to put beside it.
| Load | FiiO KA13 | iFi GO link |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Published |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. FiiO KA13 publishes at 32 Ω and at 300 Ω; iFi GO link at 32 Ω and at 300 Ω. The other rows are worked out from those.
The two publish at the same loads, which is the one case where the rows of this table can be read straight across.
4 headphones reach 100 dB on the FiiO KA13 but not on the iFi GO link — Moondrop PARA 2, Moondrop VENUS, Symphonium Triton, 1 more.
5 headphones reach 100 dB on the iFi GO link but not on the FiiO KA13 — Beyerdynamic DT 880 Edition (600Ω), Beyerdynamic DT 990 Edition (600Ω), HiFiMAN HE-6se V2, 2 more.
66 headphones are left alone by the iFi GO link under the one-eighth rule but coloured by the FiiO KA13 (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 63 more).
551 of the 567 models here reach 100 dB on both.
Headroom is at a 100 dB SPL peak.
The widest gap on the list is the Sennheiser HD 600: iFi GO link has +3 dB of headroom there against -1 dB. 4 dB is about 2.8 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for iFi GO link because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | FiiO KA13 headroom | iFi GO link headroom | FiiO KA13 hiss | iFi GO link hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +30 dB damping | +27 dB | 22 dB | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +10 dB damping | +7 dB | 2 dB | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +15 dB | +16 dB | 1 dB | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +10 dB | +14 dB | -4 dB | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +8 dB | +8 dB | -5 dB | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +3 dB | +8 dB | -11 dB | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | -1 dB | +3 dB | -15 dB | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | -3 dB | -1 dB | -17 dB | not published |
The FiiO KA13 costs $20 more than the iFi GO link. Out of the 567 models here, that difference buys 4 more models driven to 100 dB.
It does not run one way only: the cheaper iFi GO link drives 5 models to 100 dB and leaves 66 alone under the one-eighth rule that the FiiO KA13 does not, which is the part worth checking against your own headphones before paying the difference.
Only published figures count here; blank axes are counted separately.
Each in full: FiiO KA13 and iFi GO link.