  Metallic magnetic micro-calorimeters (MMCs) operated at millikelvin
temperature offer the possibility to achieve eV-scale energy resolution with
high stopping power for X-rays and massive particles in an energy range up to
several tens of keV. This motivates their use in a wide range of applications
in fields as particle physics, atomic and molecular physics. Present detector
systems consist of MMC arrays read out by 32 two-stage SQUID read-out channels.
In contrast to the design of the detector array and consequently the design of
the front-end SQUIDs, which need to be optimised for the physics case and the
particles to be detected in a given experiment, the read-out chain can be
standardised. We present our new standardised 32-channel parallel read-out for
the operation of MMC arrays to be operated in a dilution refrigerator. The
read-out system consists of a detector module, whose design depends on the
particular application, an amplifier module, ribbon cables from room
temperature to the millikelvin platform and a data acquisition system. In
particular, we describe the realisation of the read-out system prepared for the
ECHo-1k experiment for the operation of two 64-pixel arrays. The same read-out
concept is also used for the maXs detector systems, developed for the study of
the de-excitation of highly charged heavy ions by X-rays, as well as for the
MOCCA system, developed for the energy and position sensitive detection of
neutral molecular fragments for the study of fragmentation when molecular ions
recombine with electrons. The choice of standard modular components for the
operation of 32-channel MMC arrays offer the flexibility to upgrade detector
modules without the need of any changes in the read-out system and the
possibility to individually exchange parts in case of damages or failures.
