  We discuss first results from hidden photon dark matter searches made with a
prototype of the Broadband Radiometric Axion/ALPs Search Setup (BRASS-p) in the
range of particle mass of 49.63-74.44 $\mu$eV (frequency range of 12-18 GHz).
The conceptual design of BRASS and a detailed description of its present
prototype, BRASS-p, are given, with a view of the potential application of such
setups to hidden photon, axion, and axion-like particle (ALP) dark matter
searches using heterodyne detectors in the range of particle mass from
40$\mu$eV to 4000$\mu$eV (10 GHz to 1 THz). Pioneering measurements made with
BRASS-p achieve the record sensitivity of (0.3--1.0)$\times$$10^{-13}$ to the
kinetic mixing between the normal and hidden photons, assuming the dark matter
is made entirely of unpolarized hidden photons. Based on these results, a
discussion of further prospects for dark matter searches using the BRASS-p
apparatus is presented.
