Preamplifier?BNC adapter Nor1447/ L0 pages

Product Data

Preamplifier–BNC adapter
Nor1447/L
The adapter Nor1447/L consist of a

normally

self noise of a preamplifier or a sound

screened capacitor for connecting a

ships with a coupling capacitance of

The

Nor1447

adaptor

level meter, as specified in international

signal to a 1/2” microphone preamplifier

18 – 20pF which corresponds to the

standards for sound level meters IEC

like Nor1201. A BNC socket is used as

capacitance of most 1/2” microphones.

60651 and IEC61672.

the input terminal.

The device may therefore be used to test

On order, the unit can be delivered

The main application of the adaptor is

the frequency response of a preampli-

for the testing of preamplifiers and sound

fier, but be sure to use a source imped-

level meters as described in iec 60651

ance corresponding to a microphone

the adapter with a very low attenuation

and iec 61672, but it may just as well be

cartridge. If the BNC input connector

since the stray capacitance is low. The

used to connect a transducer like an ac-

is short-circuited, the device may also

Nor1447/L has a very low capacitance

celerometer to the high impedance input

serve as a microphone cartridge equiv-

and is mainly used to measure the input

of a microphone preamplifier.

alent (“dummy microphone”) to test the

capacitance of a microphone preamplifier.

with other capacitance values.
The

screened

design

provides

Specifications:
External diameter: 12,7±0,1 mm
Internal diameter for thread:
11.7 mm
Thread: 60 UNS-2B
Maximum voltage: 200 V
Input connector: BNC
Preamplifier interface:
Preamplifiers compatible with
the mechanical requirements of
IEC61094-4: Measurement microphones, Part 4, Specifications for
working standard microphones.

The inner shield
Threads to fit
preamplifier
(to make it act
like a cartridge)
The outer shield

Inner shield is connected to
signal on the low impedance
side – this will reduce stray
capacitances drastically

Capacitance: Normally 1–3 pF,
individually calibrated. Other values
in the range 2–1000 pF on request.
Stray capacitance (BNC input –
ground): 11 pF typically
Other versions available:
1147/1: C= 40 pF (1/1” mic. equivalent)
1447/2: C= 20 pF (1/2” mic. equivalent)
1447/4: C= 6.8 pF (1/4” mic. equivalent)

Certificate of calibration
Adapter type Nor1447
Serial No.:
Capacitance:tt

pF

Sign:

PD 1447/1 Ed.2 Rev.0 English 11.09

Inner shield is insulated
from the casing
Capacitor

BNC connector
in this end