The most gorgeous headphone amp ever?
I’ve recently written in our sister magazine Australian Hi-Fi about the output impedance of headphone amplifiers — about how this can affect the frequency performance of headphones, and how difficult it is to even find out what the figure might be.
Well, the Audio-Technica AT-HA5050H Hybrid Headphone Amplifier and DAC hides nothing on that front. Indeed, I’d have to say that you’ll probably be unable to find a set of headphones for which this unit isn’t an ideal fit.
Equipment
The first hint about that are the eight 6.5mm headphone sockets in a slightly recessed section of the front panel. These are grouped into four pairs. Each pair is labelled with its output impedance: 120 ohms, 82 ohms, 33 ohms and 0.1 ohms. Audio-Technica says of this: “All headphones are not the same. Each model has its own character, its own sonic signature. That’s why we’ve created a headphone amp that lets you choose from four different output impedances... to experience a sound that best suits you and your headphones.”
I am of the view that the ‘correct’ output impedance for a headphone amplifier is 0.1 ohms, or otherwise as low as possible. Very few headphone makers publish their models’ impedance curves, so how significant output impedance affects their performance
