The Neutrik TT402 and its predecessors Neutrik TP401 and MJS 401D were amazingly complex but easy-to-use instruments designed to measure signal degradation in studio and broadcast equipment. They are also suitable for measuring distorsion (THD+N) in most audio gear. While not as common and well-known as comparable Audio Precision instruments, they perform very well and are often available at a lower price point. However, there is a general lack of information about them and these pages aim to rectify that gap.

Use the left-hand menu to find out more about their history and downloadable manuals.