517:

Based on the Portico 5017 Mobile Pre, the 517 provides world class, transformer-coupled preamp, compressor and DI circuitry, with Vari-phase, Silk and DI/mic blending capabilities in a 500 series model. As the first 500 series module designed by Mr. Rupert Neve, the 517 incorporates outstanding sonic quality with an indispensable feature set.

543:

The Portico 543 Mono Compressor delivers the unobtrusive, musical-sounding dynamic control and brick-wall limiting made famous in the Portico 5043 to the 500 series format. The 543 features a fully controllable compressor-limiter with feed-forward / feedback modes, Peak / RMS detection and a built in side chain high pass filter. With an unrivaled heritage and a tremendous feature set, the 543 yields a combination of rich warmth, flexibility and precision that is sure to resonate in the ears of sound engineers the world over.