The main features of the TEAC A-400 are: 2 heads, mechanical 3 digit tape counter, manual tape type selection and capable of handling normal and chrome tapes with additional manual equalization selection, belt driven single-capstan transport.

Typical front loading cassette deck with the cassette compartiment located on the left side of the deck. Tape eject is operated mechanically and the cassette needs to be placed sideways in the cassette well.

Level meters used on the A-400 are analog needle VU reading meters with peak indicator for easy adjustment of optimum recording level. Mechanical transport controls for reliable A-400 transport function selection.

The Dolby-B system reduces tape hiss on tapes recorded on the A-400 by as much as 10 dB at the highest frequencies.

To make live recordings this deck has 2 microphone inputs to connect microphones with a jack connector. For undisturbed listening a jack connector for a pair of stereo headphones is supplied. Connection to other audio components for plaback can be achieved by a RCA cable and recording from a source by a RCA cable.