Plinth-mounted PC 4 module. Rams' revision of Wagenfeld's PC 3 module consisted in two three alterations: 1 - replacement of the organic tonearm form with one based on orthogonals, 2 - replacement of the chromed platter puck with a retractable flush-fitting disk, 3 - replacement of five rubber stabilising nubs with a continuous band of rubber. This formal emphasis on the circle and square, in place of  Wagenfeld's more complex and naturalistic references, gave the design a distinctly technical aspect. This shift was consistent with a reduction in the use of wood throughout the audio programme in the design of housings, and their replacement with lacquered or painted metal. 

Rams' revision of Wagenfeld's tonearm closely followed that proposed in Herbert Lindinger 1959 thesis proposal submitted to the Braun Company through the Gugelot Institute.

The PC 4 phono module was used in a number of devices, including the Atelier 2, Atelier 3, and SK 6/ 61. See here for PC 4 service manual.