Definition and guide
Output Impedance Without the Folklore
Why source impedance affects damping, level, and tonal balance—and when the difference is likely to matter.
The simple model
The source and headphone form a voltage divider. When headphone impedance varies with frequency, a higher source impedance can alter the delivered response.
The ratio
A low source-to-load ratio usually keeps changes small, but a nominal impedance alone may hide large frequency variation.
Damping language
Electrical damping is relevant, though broad claims about “control” should be tied to measured system behaviour.
Conclusion
Report the amplifier output impedance, inspect the headphone curve, and avoid treating either figure in isolation.