The HCM16 microphone heating module for the CM16/CMPA
microphone can increase the temperature of the microphone
capsule by about 10 Kelvin above the ambient temperature, which
should prevent condensation under difficult environmental
conditions, such as dew or rain.
The USB B connector can be connected either to a free USB port of
the PC that is running the UltraSoundGate unit or alternatively to a
separate USB power supply unit or battery.
Installation
Mount the heating module to the CM16 microphone capsule in such
a way that the resistor chips on it face outwards (see picture).
The protective grid might be still inserted between the microphone
capsule and the heating module. However, the efficiency (the
thermal contact) would be better without the grid.
Under some circumstances, the USB cable connection between the
heating module and the computer might cause electrical
interferences that are caused by a ground loop. In this case, the
ground connection to the heating module through the USB
connector should be removed (USB pin 4). This can be achieved for
instance by using a modified USB cable whose ground wire (USB
pin #4, black) has been cut. The required ground connnection to the
computer would then be established exclusively through the
microphone and the UltraSoundGate ground rail.
Specifications
Electric power requirements : 0.9 W (180 mA @ 5V)
Absolute maximum power: 3.0 W (330 mA @ 9V)
Maximum supply voltage: 9 V
Electrical impedance: 27 ohm
USB-powered microphone heating HCM16