Neumann.Berlin fet 80R (i) User manual

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

;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

2. Microphone and power supply may be converted to unbalanced

Operation

in

the field

through a minor

alteration.

This Change is

recommebded if the

microphone is to be used exclusively with unbalanced inputs such as

semi-professional

or

home equipment. Fig. 2...5

Switchcraft

A3M

t-

.-

(DIN L152t 1

Standard, balanced

configuration

of Neumann

microphone Outputs.

Fiq* 2

Switchcroft

A3M I DIN L 152t)

1

f-*-

(2)

Fiq. 3

Unbalanced

connections.

1. Wire heretofore

connected to pin 2

(+), remains

connected to pin 2

(now modulation alone).

2. Wire heretofore

connected to pin 3

(-> is to

be

resoldered

to pin 1

without removing the

wire already

connected

there.

3. Remove the Phantom

powering resistors

(2 x 6.8 kohm).

4.

Move the

wire previously

connected to the junction of these

resistors

to pin 3.

The

circuit

then

conforms to IEC 268-12.

Far

microphones

equipped with connectors per

DIN

41524

(Binder,

Mini-

Tuchel), the following changes

are necessary:

1.

Wire heretofore soldered to pin 3 (-1 is to

be

resoldered to pin. 2

without

removing

the

wire already

connected

there.

2.

Wire

heretofore

connected to pin 1

(+> is to bt-: resoldered to

pin 3.

3. Remove the Phantom pawering

resistors.

4. Install a

new

wire

from the

junction

of these

resistors

to pin 1.

The

circuit

then

corresponds to DIN 45594

Type L.

The

IC 3, IC 4,

KT

1 tiicrophone Cables require

no changes.

Conversion

of the N 452 i, BS 945 i etc. Power Supplies:

+L8V-

.-

+4--

6k8

J

Switchcraft

A3F

1-

6k8

T

I

1

x

/

-t:

I

ov

T

1

i’-

A3M

.-

#

.

3 ov

.

+

2 w Modulation

-&=l OV, Schirm

L,-

Shield

i

Fig. 4

11)

12 1

11)

131

(2)

1. Remove and

discard

the 6.8 kohm

resistor soldered

to pin 2.

2. Remove and

discard

the

wire heretofore

connected to pin 3 (output

side).

3. Strap

pin 1 and pin

3 together

(output

side).

For microphones

equipped with

connectors per

DIN 41524, the following

applies :

The pin numbers

of

Figs, 1, 2, 3 correspond

to the pin numbers 2, 3, 1

in this

order

(sec also the schematic

supplied

with

your

equipment) .

Audio Modulation cable to the amplifier, tape recorder etc. equipped

with unbalanced input:

i DIN‘L152L 1 Switchcraft

w Modulation

Schirm

Shield

Fig. 5

3. Should the use of a transformer

as recommeded

in example #l not be desi-

rable or the microphone put out’modulation voltages beyond those permis-

sable for the AT 8/‘l (i) transformer, then you may block the 48 Vdt phan-

tom power from your

input through the use of blocking capacitors:

Switchcroft

-iz3L-dbfF

‘6k8 6k8

I I

‘< 2 ‘< 2

6k8 6k8

. .

1 1

2x + 2x + ; ;

+L8V- +L8V-

lOOp163V lOOp163V

T

I

Fig. 6

( DIN L152L 1

(3)

11)

(2)

;

(3)

Pin numbers in

parentheses refer to microphones equipped with connectors

according to DIN 41524 (Binder or

Amphenol-Tuchel).

Errors excepted.

Subject to changes.

Neumann.Berlin fet 80R (i) User manual

Neumann.Berlin fet 80R (i) User manual

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