Product Data Preamplifier–BNC adapter Nor1447/L The adapter Nor1447/L consist of a self noise of a preamplifier or a sound screened capacitor for connecting a ships with a coupling capacitance of level meter, as specified in international signal to a 1/2” microphone preamplifier standards for sound level meters IEC like Nor1201. A BNC socket is used as capacitance of most 1/2” microphones. 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 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 celerometer to the high impedance input serve as a microphone cartridge equiv- and is mainly used to measure the input alent (“dummy microphone”) to test the capacitance of a microphone preamplifier. with other capacitance values. The 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: Inner shield is insulated from the casing Capacitor