Neumann M 147 Tube microphone
The M 147 Tube is a vacuum tube condenser microphone with cardioid characteristic. At the heart of this microphone is the K 47 dual diaphragm capsule, inherited from this model’s now legendary predecessors, the U 47 and the M 49.
Following the capsule is a tube that functions as an impedance converter. The next stage is an efficient, transformerless output circuit, that guarantees an extremely low self-
The M 147 Tube can feed extremely long microphone cables without affecting the quality of the audio signal. Like all Neumann tube microphones, the M 147 Tube comes with an elegant satin nickel finish.
The microphone is delivered as a complete set in a high-
Similar to the recently introduced M 149 Tube, the new M 147 Tube combines a specifically selected vacuum tube (triode) with modern circuitry. This technique takes full advantage of the special transfer characteristics of the tube and passes the processed audio signal of the capsule to the microphone output, without any coloration or unwanted side effects.
The tube amplifies the capsule’s signal by approximately 10 dB, thus preventing any possible influences from subsequent electronics. The M 147 Tube delivers a high output voltage, and therefore can feed microphone cables up to 300 m length without signal degradation.
The ideal operating conditions (anode current, heater voltage) of the tube are maintained throughout its life expectancy. A sensor lead detects any voltage drop that occurs through the microphone cable and compensates for it in the N 149 A power supply. The tube warms up gradually using inverse current limiting to guarantee long life. FilterThe electronic circuitry of the M 147 Tube mic has a flat frequency response from 20 Hz to well above 20 kHz. Only the attributes of the capsule determine the typical sound characteristics of the microphone. Operational StabilityBoth, the capsule and the entire circuitry are shock mounted to prevent any structure-
This implies that the microphone may also be sensitive to unwanted LF interference by structure-