The Abyss AB-1266 Phi TC is 50Ω at 88.0 dB/mW; the AKG K612 Pro is 120Ω at 91.8 dB/mW. This page is only about what they ask of an amplifier — not how they sound, which no specification on either sheet can tell you.
The Abyss AB-1266 Phi TC needs 3.8 dB more than the AKG K612 Pro to reach the same loudness — 16 mW against 6.6 mW.
| Specification | Abyss AB-1266 Phi TC | AKG K612 Pro |
|---|---|---|
| Impedance | 50 Ω | 120 Ω |
| Sensitivity | 88.0 dB/mW | 91.8 dB/mW |
| Sensitivity (voltage) | 101.0 dB/V | 101.0 dB/V |
| Power for 100 dB | 16 mW | 6.6 mW |
| Voltage for 100 dB | 0.89 V | 0.89 V |
| Current for 100 dB | 17.8 mA | 7.4 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 6.25 Ω | 15.00 Ω |
| Sources that reach 100 dB out of 280 | 275 | 277 |
2 of the 280 sources have the power for the AKG K612 Pro but not for the Abyss AB-1266 Phi TC — Zoom AMS-22, Tascam US-2x2HR.
17 sources are low enough in output impedance for the AKG K612 Pro under the one-eighth rule but not for the Abyss AB-1266 Phi TC (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 14 more).
275 of the 280 sources here reach 100 dB on both. That count is about power only — the output-impedance and hiss lines above are separate questions, and a source can pass this one and fail those.
Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: Abyss AB-1266 Phi TC and AKG K612 Pro. Every figure on this page comes from what Abyss and AKG published, or is derived from it — what Abyss publishes and what AKG publishes, both counted.