The MP 5.12 is based on one discrete Op-Amp, one Cinemag input transformer and one Cinemag 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 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' format of API.
The MP 599 is based on one SK99 discrete Op-Amp, one Lundahl input transformer and one Lundahl output transformer.
