Form Factor
Headphone Amplifier Form Factor describes the amplifier’s physical format, such as desktop, portable, USB dongle or rack-mount.
The format helps identify how the amplifier is intended to fit into a listening setup. It is separate from its circuit technology, output power and audio connections. Products in the same format can differ substantially in power supply, controls and supported headphones.
Form Factor — Headphone Amp
A desktop unit sits beside other equipment, while a portable unit is intended to travel with the source. A USB dongle is compact and connects directly or through a short lead; a rack-mount unit fits a supported rack arrangement. Check actual dimensions and mounting requirements rather than relying on the label.
Portable does not necessarily mean battery-powered, and a small USB device can depend on power from the connected source. Likewise, a large enclosure does not establish higher output capability. Compare the required power source, input support and headphone compatibility alongside the physical format when planning the system.