Neumann U47 Vintage
Microphone
Why Neumann
is the unquestionable best in microphone
history
Built by
Telefunken as a special tube for field radios during World War
II, George Neumann decided that this tube was perfect to use as
the amp in a high quality condenser microphone. However, the
number of VF14's was very limited. This tube disappeared from
the market completely by the seventies. Since about 1980 it has
been nearly impossible to find a VF14 for sale unless you’re
prepared to pay massive quantities of money. Only a handful of
unused spare ones world-wide are available, and these are
generally held onto by their owners.
Some modification alternatives came up to replace the original
tube with other types, the first suggestion coming from Neumann
in June 1968 for replacing a Nuvistor tube 13CW4. However, this
and most of the other ideas have never caught on in popularity
because the output transformer of the U47 was actually designed
for the low output impedance and the enormous high output level
of the VF14. As a result, most replacement modifications
seriously compromised the performance of the U47 resulting in
significant loss of bass amongst other things. The
modifications very often turn the classic U47 into a decorative
item instead of a great microphone, prioritizing form over
function.
The Capsule
The M7 type is the capsule used for the original early U47.
This was also used in the U48 and the M49. It has a slightly
different sound quality than the K47 Neumann used in later
models of the U47. While Neumann's later K47 capsules have a
flat ring with many tiny screws to mount the diaphragm, the M7
capsule does not have this because the diaphragms are glued
directly onto the body.
Made of brass, the body of the capsule contains more than 100
tiny holes per side, located with precision. Removing the grill
won’t help you see these holes, since they are hidden behind
the diaphragms. Do not touch the diaphragms. The diaphragms are
made of polyester and fit over the body with just a few microns
to spare. The diaphragms have a thin circular layer of gold
evaporated onto the surface to create the "moving" conductive
part of the condenser. The tension and strength of the
polyester change through the passing of years. The diaphragms
in worst cases may become perforated, or the thin film might
crack, losing all flexibility. These problems might cause
bottom and top end, crackling noises and sometimes even total
cut-outs at high sound pressure levels.
The mains voltage for the U47/U48 was designed for exact 220V
or 110V mains supply. If you use this microphone or in one of
the countries with different mains voltage (UK, AU) make sure
that your power supply has been properly
modified.
Wunder CM7 Tube Microphone CM-7 Neumann U47 Clone
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Telefunken Neumann U47 BLUE MOD EF 86 Microphone Mint
NEUMANN K47/ K49 CAPSULE for U47/ M49 etc. MICROPHONES
The Neumann U47, one of the finest microphones of all
time!
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