Short answer
Both are desktop amplifiers, $1995 against $2499.
The iFi Pro iCAN Signature reaches 100 dB on 567 of the 567 models here, the Ferrum OOR on 566.
| Specification | Ferrum OOR | iFi Pro iCAN Signature |
|---|---|---|
| Power into 32Ω | 1.1 W | 2.4 W |
| Power into 150Ω | 800 mW | 512 mW |
| Power into 300Ω | 400 mW | 256 mW |
| Power into 600Ω | 200 mW | 128 mW |
| Output impedance | 0.3 Ω | not published |
| Output noise | 1.5 µV unverified | not published |
| Price | $1995 | $2499 |
| Headphones it reaches 100 dB on out of 567 | 566 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | Ferrum OOR | iFi Pro iCAN Signature |
|---|---|---|
| Socket | XLR4 | XLR4 + 4.4mm + dual XLR3 |
| Power into 32Ω | 4.3 W derived | 7.0 W derived |
| Power into 300Ω | 1.6 W | 747 mW derived |
| Output impedance | 0.3 Ω | not published |
| Output noise | not published | not published |
| Headphones it reaches 100 dB on out of 567 | 567 | 567 |
Through the balanced sockets the two are level on the same test: each reaches 100 dB on 567 of the 567 models here. Derived figures are worked out from the loads the maker did publish.
| Load | Ferrum OOR | iFi Pro iCAN Signature |
|---|---|---|
| 32 Ω | Derived | Derived |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Derived |
| 600 Ω | Derived | Derived |
Only one of these two columns starts from a power rating. Ferrum OOR publishes one at 300 Ω; iFi Pro iCAN Signature publishes none at any of these four loads, so its column is worked out from power it published at other loads. Both are arithmetic on a maker’s own figures rather than guesses, and the method used for the iFi Pro iCAN Signature understates rather than flatters — but at 300 Ω is the only load here at which its maker can be held to a figure.
1 headphone reaches 100 dB on the iFi Pro iCAN Signature but not on the Ferrum OOR — Symphonium Titan.
566 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 Shure SE846: iFi Pro iCAN Signature has +48 dB of headroom there against +39 dB. 10 dB is about 9 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Ferrum OOR and iFi Pro iCAN Signature because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Ferrum OOR headroom | iFi Pro iCAN Signature headroom | Ferrum OOR hiss | iFi Pro iCAN Signature hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +39 dB | +48 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +19 dB | +28 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +33 dB | +31 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +29 dB | +27 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +20 dB | +26 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +22 dB | +20 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +18 dB | +16 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +16 dB | +14 dB | not published | not published |
The iFi Pro iCAN Signature costs $504 more than the Ferrum OOR. Out of the 567 models here, that difference buys 1 more model driven to 100 dB.
Nothing runs the other way: there is no axis here on which the cheaper of the two does better.
Only published figures count here; blank axes are counted separately.
Each in full: Ferrum OOR and iFi Pro iCAN Signature.