The MP573 is a two stages, single ended class A preamp, based on the design that was originally used in the Neve 1290/1073 modules, that has been adapted to the 500 series of API.

The MP 512 is based on one discrete Op-Amp, one Cinemag input transformer and one Cinemag output transformer.

The MP 599 is based on one SK99 discrete Op-Amp, one Lundahl input transformer and one Lundahl output transformer.

The MP566 is a dual-triode vacuum tube circuit preamplifier based on a design that has been used in several famous devices from the 50's, which has been adapted to the '500' format of API*.

The DI503J is a triple mode Direct Box for instrument and a Re-Amp unit for the '500' format of API*.

The AB528 is a transformers coupled, class A mic preamp. The design, from the late 60's, is inspired by a legendary console, that was used at the most famous London studio by the greatest artists, such as the Beatles or Pink Floyd.