Both are desktop amplifiers, $1800 against $1995. This page puts them side by side on the only three things a maker can be held to — power, output impedance and noise — and then asks the question that actually matters: which headphones do they treat differently?
The Cayin HA-6A reaches 100 dB on 567 of the 567 models here, the Ferrum OOR on 566.
| Specification | Cayin HA-6A | Ferrum OOR |
|---|---|---|
| Power into 32Ω | 3.0 W | 1.1 W |
| Power into 150Ω | 1.5 W | 800 mW |
| Power into 300Ω | 900 mW | 400 mW |
| Power into 600Ω | 450 mW | 200 mW |
| Output impedance | 2 Ω unverified | 0.3 Ω |
| Output noise | 25 µV unverified | 1.5 µV unverified |
| Price | $1800 | $1995 |
| Headphones it reaches 100 dB on out of 567 | 567 | 566 |
A figure marked not published is missing from the maker’s own material, which is not the same as being good or bad. Where one of these two publishes a number and the other does not, the comparison on that axis cannot be made at all — and saying so is more useful than guessing.
1 headphone reaches 100 dB on the Cayin HA-6A but not on the Ferrum OOR — Symphonium Titan.
566 of the 567 models here reach 100 dB on both. That is a power count and nothing more; whether either source suits a given headphone also depends on the two lines above.
Each has a page of its own with a full headphone list and the provenance of every figure — worth opening here, because Cayin HA-6A has published no electrical specification at all and everything above comes from independent measurement: Cayin HA-6A and Ferrum OOR. Or put either against your own headphones in the source comparison tool.