Neumann-Information 1841
NOV.
I 984
Operation
of
NEUMANN
fet
80R(i)
microphones
in
conjunction
with
unba-
lanced
or
Center
tap
grounded
inputs
The
microphones
of
the
fet
80
R
(i)
series
are
Phantom
powered
from
48
Vdt
according
to IEC 268-15A/DIN 45, 596.
In
Phantom
powering
both
modulation
conductors
of
the
microphone cable as
-weil
as the
modulation
leaving
the
power
supply
are at the powering voltage
potential
of
+48
Vdt.
For
professional
balanced
and
floating
amplifiers
and
console
inputs
this
is
of
no consequence.
However
when
such
Phantom
powered
microphones
are
connected
to
inputs
which
have
side
or the
Center
tap
grounded,
the
powering voltage
is shorted
out
and
no
Operation
is
possible.
For Center tap grounded
equipment
with
an input
transformer
(e.g.some
NAGRA
NAGRA
recorders),
this
Center
tap
ground tan virtually
always
be
discon-
nected
without
causing
any negative
operational
results.
For
connection
af
NEUMANN
fet
80
R
microphones
to
unbalanced
inputs,
there are
the
following
possibilities:
1.
Microphone
and
power
supply
may be
operated
without
any
alterations
even
into
unbalanced
or Center
tap
grounded inputs,
if
a
high
quality
cable
transformer
(1
:l
turns
ratio)
of
the
AT 8/1
(i)
type
is
inserted
into
the
modulation
line.
Since
there
are numerous
types
of
microphone
input
connectors,
this
transformer
is
supplied
with
stripped
and
tinned
secondary
leads only.
A specific
connector
will
be
attached
to the secondary
on
special
Order
and
at
additional
price.
The maximum
input
Signal
capability
of
the
AT 8/1
(i)
is
300
mV at
40 Hz;
frequency range is
30...16,000
Hz.
Fig.
1
Bu 1
5u 1
+--20cm
4
b--
30cm
---+
INTERNATIONAL
DIN
PRIMARV
SEKUNDARV
i
.
-
MICROPHONE
(150..
250a.h)
Bu 1
Bu 1
;NTEANATIONAL
DIN
0
ty$
AT811
i
Soldering side vietq
Fiq.
1
GN7
CHARLOTTENSTRASSE
3 . D-l000
BERLIN 61 I POSTFACH
610469
. TELEGRAMM:
NEUMANNACUSTIC
TELEFON:
(030) 25993-0
. TELEFAX:
(030) 25993-108
. TELEX: 184595
NEUAK D
Printed in Germany