Short answer
Both are portable players, $1999 against $1799.
The FiiO M17 reaches 100 dB on 567 of the 567 models here, the Cayin N7 on 565.
| Specification | Cayin N7 | FiiO M17 |
|---|---|---|
| Power into 32Ω | 250 mW | 500 mW |
| Power into 150Ω | 53 mW | 115 mW |
| Power into 300Ω | 27 mW | 63 mW |
| Power into 600Ω | 13 mW | 32 mW |
| Output impedance | 0.6 Ω | 1 Ω |
| Output noise | not published | 3.5 µV |
| Price | $1999 | $1799 |
| Headphones it reaches 100 dB on out of 567 | 565 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | Cayin N7 | FiiO M17 |
|---|---|---|
| Socket | 4.4mm | 4.4mm |
| Power into 32Ω | 500 mW | 3.0 W |
| Power into 300Ω | 53 mW derived | 250 mW |
| Output impedance | 1.2 Ω | 2 Ω |
| Output noise | not published | 7 µV |
| Headphones it reaches 100 dB on out of 567 | 566 | 567 |
Through the balanced sockets the FiiO M17 reaches 100 dB on 567 of the 567 models here and the Cayin N7 on 566. Derived figures are worked out from the loads the maker did publish.
| Load | Cayin N7 | FiiO M17 |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Published |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. Cayin N7 publishes at 32 Ω; FiiO M17 at 32 Ω and at 300 Ω. The other rows are worked out from those.
So the two columns are not equally firm row by row: at 300 Ω only the FiiO M17 figure is the maker’s own. On those rows the derived number is the one to doubt first.
2 headphones reach 100 dB on the FiiO M17 but not on the Cayin N7 — Moondrop PARA, Symphonium Titan.
14 headphones are left alone by the Cayin N7 under the one-eighth rule but coloured by the FiiO M17 (64 Audio Nio, 64 Audio Volur, Campfire Audio Andromeda 2023, 11 more).
565 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 Campfire Audio Andromeda 2020: FiiO M17 has +20 dB of headroom there against +12 dB. 8 dB is about 5.9 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Cayin N7 because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | Cayin N7 headroom | FiiO M17 headroom | Cayin N7 hiss | FiiO M17 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +32 dB | +40 dB | not published | 25 dB |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +12 dB | +20 dB | not published | 5 dB |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +22 dB | +25 dB | not published | 3 dB |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +17 dB | +21 dB | not published | -1 dB |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +14 dB | +19 dB | not published | -2 dB |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +10 dB | +14 dB | not published | -8 dB |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +6 dB | +10 dB | not published | -12 dB |
| HiFiMAN Susvara | 60 Ω | 50 mW | +4 dB | +7 dB | not published | -14 dB |
The Cayin N7 costs $200 more than the FiiO M17. Out of the 567 models here, that difference buys 14 more models left alone under the one-eighth rule.
It does not run one way only: the cheaper FiiO M17 drives 2 models to 100 dB that the Cayin N7 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.