This classical pattern control unit contains a mains transformer. It automatically switches between the 100-120 V and 220-240 V ac mains voltage ranges.
In the OFF position the NM V draws no current.
To ensure a long life, the tube is heated up gently, with current limiting. A very effective filtering inside the NM V ensures very high-quality operating voltages, with a minimum of residual noise voltages.
Note: The new NM V is suitable in principle for operating all vintage Neumann microphones utilizing the AC 701 tube, such as the older M 49 and M 249.
Older devices as N 52 (a, h) and NN 48 (a, b, h) are not suitable for operating the M 49 V, due to their current and voltage limitations.
Operation with Unbalanced Inputs
At the pattern control unit, the audio signal isavailable at a balanced, floating XLR 3 output. The output is wired as per IEC 60268-12 and IEC 61938:
Pin 1: 0 V/ground
Pin 2: audio signal (+phase)
Pin 3: audio signal (–phase)
So pin 2 is the “hot phase”, pin 3 must be connected to ground when used with unbalanced inputs