Mic Archive
Neumann U 47
Photo: Neumann, from its history, p. 1.

Neumann

Neumann U 47

Large-diaphragm tube condenser, cardioid or omni (switch on the body), VF 14 tube; made 1949 to 1965, discontinued

Approximate Some readings for this mic are uncertain; see the graphs.

Type
Condenser
Pattern
Cardioid / omni
Sensitivity
−32 dBV/Pa computed
Max SPL
110 dB SPL
Impedance
200 Ω
Rated range
35 – 15k Hz

Frequency response

Angle
Distance

Frequency response: from the brochure 1958, p. 1. 1958 brochure, strip "Stellung" cardioid symbol (U 47 and U 48); no title or measuring conditions printed. dB relative; the strip is drawn from +10 to -5 dB.

Dashed: outside the rated range, or simulated (other angles and distances). Hover or tap the graphs for values.

Polar pattern

Polar pattern: from the brochure 1958, p. 1. 1958 brochure, the middle plot, cardioid (shared by U 47 and U 48); no title or measuring conditions. Rings every 5 dB to -25 dB, centre -30 dB. Both halves drawn; the two are averaged here. Approximate reading error up to about 1 dB.

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All specs

From the manual
Sensitivity−32 dBV/Pa (25 mV/Pa), cardioid, 1 kHz, into 1000 ohm; also −37.1 dBV/Pa, omni, 1.4 mV/µbar (1958 brochure); also −30 dBV/Pa, 1949 brochure: "Sensitivity (reference level 1 Volt / µb) -50 db" (pattern not stated). Not stated by the manufacturer: From 2.5 mV/µbar = 25 mV/Pa: 20·log10(0.025).p. 1
Max SPL110 dB SPL, less than 0.8% THD at 1 kHz; also 120 dB SPL, less than 1% THD (undated brochure: "Klirrfaktor bis 120 phon < 1%"). "Total Harmonic Distortion less than 0.8% (at 1000 cps) up to a sound pressure level of 110 db". The 1958 brochure: "< 0,8% bis zu einer Lautstärke von 110 phon (1000 Hz)".
Output impedance200 ohm, or 50 ohm, strapped on the output transformer; also 50 ohm, strapped for a 250 ohm load (marked with a red dot on the type tag). "Source Impedance 200 or 50 ohms". Re-strapping is done on the terminal board inside the housing.
Rated load impedance1000 ohm, for the 200 ohm setting; 250 ohm for 50 ohm. "designed to work into a load impedance (input impedance of console preamplifier) of 250 respectively 1000 ohms, or even higher"; the source impedance is about one fifth of the load.
Rated frequency range35 Hz to 15 kHz; also [30, 15000], undated brochure ("30-15 000 Hz"); 1949 brochure: "up to 30 cycles ± 2 db up to 16 000 cycles ± 3 db" (re 1000 cycles). "Useable Range of Frequencies 35 to 15,000 cps". The 1958 brochure: "35 ... 15000 Hz".
PoweringNG mains power supply: 105 V DC, 40 mA, one voltage for anode and heater. "Operating Voltage 105 volts D.C. (40 ma) (the heater voltage is taken from the 105 volt supply)"; NG for 110/220 V mains, 50-60 cps. The brochures say 100 V, 40 mA.
Current draw40 mA. From the NG power supply, at 105 V DC.
Connector6-pin Tuchel plug in the base. "special 6-pin plugs in their base, the No. 5 pin carrying the D.C. supply voltage ... purposely shortened". The undated brochure names it "6poligen Tuchelkontakt (T. 2045)" (p. 2).
Supplied accessoriesNG power supply; UC 4 cable (10 m) with swivel stand mount. "Interconnecting Cable UC 4: Standard Length 33 ft. (other lengths on request); Stand Mount ½" right-hand thread (5/8-27 thread on request)".
TubeVF 14 M (Telefunken), selected for low noise; a pentode run as a triode
Warm-up timesomewhat over one minute
U 48Sibling model (1957): identical except for cardioid and figure-8 patterns; a U 47 head fits a U 48 but not the other way round
SuspensionZ 37 full-elastic suspension for film and TV booms
From the brochure 1958
Weight700 g; also 800 g, 1949 brochure and Telefunken U 47 M sheet 1952 ("0,8 kg"). "Gewicht: 0,7 kg".p. 1
Dimensions63 × 240 mm. "Abmessungen: 240 mm lang; 63 mm Ø": diameter x length. The product page: the housing was shortened by 23 mm towards the end of the 1950s ("long body" and "short body").
Equivalent loudness (DIN 5045)cardioid about 15 phon, omni about 20 phon
Dynamic rangeabout 100 dBp. 2
Low-frequency roll-offThe output transformer is designed to fall off steadily below 35 Hz, against structure-borne noise
Power supply NG110/220 V mains, 15 W; 105 V DC at 40 mA; hum voltage about 5 µV; 220 x 100 x 120 mm, 2 kgp. 1
From the product page
CapsuleDual-diaphragm large-diaphragm capsule (M 7, later K 47). "The transducer chosen for the U 47 was the M7 dual diaphragm condenser capsule"; towards the end of the 1950s it was replaced by the K 47, "a re-engineered version using same capsule acoustics" with polyester instead of PVC diaphragms. The brochures say "Doppelmembransystem".p. 1
VersionsLong body and short body (housing 23 mm shorter from the late 1950s); M 7 capsule, later K 47 with polyester diaphragms; basket polished, later satin nickel
ProductionIntroduced 1949, discontinued 1965; the transistor U 47 fet followed in 1972
From the brochure undated
Noise voltage at the outputabout 1.5 µVp. 2
Pattern switchSlide switch at the base of the mesh head; the symbol in the oval window shows the pattern and the front of the mic
From the nuvistor 1968
Nuvistor conversionFrom 1967 Neumann offered a conversion to the 13 CW 4 nuvistor after Telefunken stopped making the VF 14; output 2 to 3 dB lowerp. 1
From the brochure 1952
TelefunkenAlso sold by Telefunken with its logo, as the U 47 M ("Telly")p. 1

Documents

Copies kept by Mic Archive, because manufacturers move and drop their documents. Each is © Neumann, unchanged, with its original address.

Product page on neumann.comRecording Hacks

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