
he M 147 Tube is a vacuum tube condenser microphone with cardioid characteristic. At the heart of this microphone is the K 47/49 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 selfnoise level. Note: This innovative combination of current
tube technology with the most advanced solid-state circuitry
was decisive in awarding the 1997 TEC Award to the
related M 149 Tube mic.
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 highquality aluminum case. Included with the microphone are
a microphone cable, a metal swivel mount for a mic stand,
and a compact universal power supply for standard mains
sockets. Our modern manufacturing methods makes it possible to offer this complete set at a very attractive price.
Applications
Features
• Universal tube microphone
• Pressure gradient transducer with the large diaphragm capsule
from the legendary U 47 and M 49
• Transformerless circuitry
• Low self noise level
• Comes with swivel stand mount made of metal, universal power
supply, and cable in an attractive aluminium case
Application Hints
• Vocalist mic: its warm and yet transparent sound gives volume
and presence
• Announcer’s mic for broadcasting/voice over
• Spot mic for close miking of solo instruments, especially strings,
wind instruments, and piano
These are just some of the most common applications. We
recommend additional experimentation to gain maximum use
from this microphone.
The famous capsule, together with complimenting tube
characteristics, makes the M 147 Tube especially well suited as a vocal mic. In addition, it is a superb spot mic for all
types of musical instruments.
The extremely low self-noise of its tube circuitry makes the
mic perfectly suited for use in modern recording chains,
analog and digital.
Acoustic Features
The M 147 Tube is addressed from the side where the
microphone body has the diamond-shaped Neumann company logo. The black color identifies tube microphones.
The capsule is equivalent to the one used in the U 47, and
is the deciding factor in determining the sound characteristic. It has a flat frequency response to the upper midrange,
and a boost of up to 3 dB above 2 kHz.
The headgrille design is a smaller version of the U 47. It protects the capsule effectively against popping and wind noise.
Polar Pattern
The M 147 Tube has a cardioid characteristic, leaning more
toward super-cardioid due to its distinctive capsule design.
At higher frequencies the pattern becomes more directional. This is very similar to the model after which this new
tube microphone was patterned, the U 47 and the successor, the U 47 fet.
Delivery Range
M 147 Tube microphone,
N 149 A power supply incl. power cable, SG 1 swivel mount,
KT 8 microphone cable, dust cover, aluminium case
Catalog No.
M 147 Tube (230 Volt, EU) ...................................ni ............... 008435
M 147 Tube (117 Volt, US) ................................... ni ............... 008434
M 147 Tube (230 Volt, UK) ................................... ni ............... 008436
Selection of Accessories
Elastic suspension, EA 1 ............................................ ni ............... 008449
Elastic suspension, EA 1 mt ....................................blk ............ 008450
Auditorium hanger, MNV 87 .................................. ni ............... 006804
Auditorium hanger, MNV 87 mt .......................... blk ............ 006806
Table stand, MF 3 .......................................................... blk ............ 007321
Table stand, MF 4 .......................................................... blk ............ 007337
Stand extension, STV 4 ............................................... blk ............ 006190
Stand extension, STV 20 ............................................ blk ............ 006187
Stand extension, STV 40 ............................................ blk ............ 006188
Stand extension, STV 60 ............................................ blk ............ 006189
Popscreen, PS 15 ............................................................ blk ............ 008472
Popscreen, PS 20 a ....................................................... blk ............ 008488
Windscreen, WS 87 ...................................................... blk ............ 006753
Microphone cable, IC 3 mt ....................................... blk ............ 006543
A complete survey and detailed descriptions of all accessories
are contained in the accessories catalog
Meaning of color codes: blk = black, ni = nickel

M 147 Tube
Electrical Features
When compared to other microphones, the impedance converter used in the M 147 Tube is distinguished by its extremely low self-noise level of only 12 dB-A / 24 dB CCIR
weighted.
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 and 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.
Filter
The 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.
N 149 A Power Supply
The N 149 A universal power supply works with all mains
AC voltages from 100 V to 240 V, 50 or 60 Hz. Mains
power is connected through a standard IEC 320
mains socket. The only difference between the
three versions of the M 147 Tube set is the
power cord supplied. Note: The N 149 V
power supply is fully compatible
with the M 147 Tube microphone.
Operational Stability
Both, the capsule and the
entire circuitry are
shock mounted to
prevent any structure-borne
noise.
Because of
its wide operating range, the
M 147 Tube
can reproduce
extremely low
frequency signals
without distortion.
This implies that the microphone may also be sensitive to unwanted LF interference by structure-borne noise, or wind
noise. To avoid possible signal degradation, we offer the EA 1
elastic suspension and the WS 87 windscreen as accessories.
During close miking of vocals we recommend using the PS 15
or PS 20 a pop screen. You will find detailed information in
our accessory catalog.

Technical Data
measured in free-field conditions (IEC 60268-4)
M 147 Tube
Acoustical operating principle ................................ Pressure gradient transducer
Directional pattern .................................................................................................... Cardioid
Frequency range ..................................................................................... 20 Hz...20 kHz
Sensitivity at 1 kHz into 1 kohm .............................................................. 20 mV/Pa
Rated impedance ................................................................................................... 50 ohms
Rated load impedance .................................................................................. 1000 ohms
Signal-to-noise ratio, CCIR1) (rel. 94 dB SPL) .............................................. 70 dB
Signal-to-noise ratio, A-weighted1) (rel. 94 dB SPL) ................................ 8 2 dB
Equivalent noise level, CCIR1)................................................................................. 24 dB
Equivalent noise level, A-weighted1)............................................................ 12 dB-A
Typical SPL (tube characteristic)2):
for < 0.5% THD (for < 5% THD) .................................................. 114 (134) dB
Selection of Accessories
Elastic suspension,
EA 1 (mt)
Table stand, MF 3 (in
connection with stand extension)Auditorium hanger, MNV 87 (mt)
Maximum output voltage ........................................................................................8 dBu
Dynamic range of the microphone amplifier:
(A-weighted) for < 0.5% THD (for < 5% THD) ................. 102 (122) dB
Powering..................................................................................... Power supply N 149 A
Matching connector microphone .................................................................... D IN 8 F
Matching connector power supply ................................................................. XLR3F
Weight.................................................................................................................................460 g
Diameter ......................................................................................................................... 57 mm
Length........................................................................................................................... 142 mm
1)
according to IEC 60268-1; CCIR-weighting acccording to CCIR 468-3,
quasi peak; A-weighting according to IEC 61672-1, RMS
2)
measured as equivalent el. input signal
Table stand, MF 4 (in
connection with stand extension)
Stand extensions,
STV 4 /20 / 40 / 60
Windscreen, WS 87Popscreen, PS 20 aPopscreen, PS 15 Microphone Cable, IC 3 mt
Adapter Cable, AC 25