What does “Zero-Ohm Headphone Outputs” mean?

“Zero-Ohm” refers to the impedance of the headphone output circuit, which is not exactly 0 ohms, but really close (0.5 ohms).

More importantly, why is this an important feature?

The Zero-ohm headphone output is important for these two reasons;

  1. The performance of your headphones (even frequency response, maximum output level) is highly dependent on the ratio between its impedance and the source impedance of the headphone output.
  2. The impedance and sensitivity of headphones available today varies (maybe even wildly!).

The best way to ensure the ideal impedance ratio between your headphones and our headphone output, regardless of your headphone make and model, is to make the output impedance as low as possible. The only possible issue is with output power - if the headphone output is powerful enough to drive high impedance headphones, it could overload low impedance headphones and earbuds.