Preamplifier cables are an important part of a measuring system. Broken cables or low quality connectors cause many problems. It is therefore important that the microphone preamplifier cables and connectors are made of high quality material that withstand rain, extreme temperatures and mechanical stress. Norsonic has a therfore developed a wide range of microphone preamplifier cables and adaptors well suited for all applications.
The Norsonic ”blue” preamplifier cable is a high performance, yet thin and flexible cable for use with Norsonic range of preamplifiers as well as other leading manufactures of acoustical instrumentation, following the 7 pin Lemo 1B standard, once developed by Norsonic, and later adopted by almost all manufactures.
The Norsonic microphone cable is made of high flexible copper wires coated with silver, each conductor insulated with Teflon, a material that has an extremely low absorption of water. This ensures high insulation under all environmental conditions and therefore no risk of leakage of the 200V polarisation voltage when cables are used in the field. The tinned copper braided screen give a high shielding effect to high frequency electromagnetic fields as well as low frequency fields such as the mains frequency.
The outer insulation is made of Polyurethane, a strong and flexible material even at low temperatures. The Norsonic microphone cable is also special treated with a material doped into the Polyurethane to ensure a low friction and highest possible flexibility.
Polyurethane is superior too PVC and silicone. Although PVC is attractive since it is a low-cost material, it has the disadvantage of becoming non-flexible at low temperatures and being unacceptably weak when it comes to mechanical stress. Silicone is a more flexible material than Polyurethane; the main drawback is its sensitivity to mechanical stress. It is therefore not considered suitable for field use.
The capacitance is kept at a minimum, and is typically 80pF/m. Suitable operating temperature range is -40 to +105 oC. Cable diameter is 4.8mm.
The Norsonic preamplifier extension cable comes in several versions. Common for all are the use of high quality cable and connectors with gold plated contact pins and the connector housing is protected with a special rubber sleeve (Nor1408A only). This protects the connectors in use from moisture, dirt and bumps.
A waterproof version of the cable system is also available (Nor1485). This enables the use of the cables down to a water depth of 100m. The waterproof cable systems require use of adaptors (Nor1475 and Nor1476) in both ends of the Nor1485 cable in order to enable a connection of waterproof connectors to standard Lemo connectors.
The Nor1408A cable are delivered in several lengths. Standard lengths are 5, 10, 20, 30 and 50 metres. Other lengths available on request. The Nor1440 comes with a Brüel & Kjær male plug (B&K type JP0715) in the one end and a Lemo female connector in the other end. This cable is used for adapting the Norsonic preamplifier to measuring equipment with B&K socket. Standard length is 10m. Other lengths upon request. Frequently, a 2m cable is sufficient. Hence both 1408A and 1440 are available in 2m versions, but under separate names and without the special rubber sleeve. A 2m Lemo/Lemo cable is referred to as Nor1410A while a 2m B&K/Lemo cable is referred to as Nor1406
Microphone attenuators are placed between the microphone and the preamplifier in order to extend the maximum sound pressure level a Sound Level Meter can measure. The maximum sound pressure level a Sound Level Meter can measure is either determined by the microphone or the electrical performance of the Sound Level Meter. In the latter case a microphone attenuator will prove useful, as it will prevent the microphone output voltage from overloading the microphone preamplifier or the input amplifier stage of the Sound Level Meter.
The microphone attenuator will not change the maximum sound pressure level the microphone cartridge itself can measure.
The microphone attenuator Nor1260 provides about 20dB attenuation when used with a ½” microphone. All attenuators are individually calibrated.
The adaptor has not an integral guard ring. Hence, the adaptor adds a small attenuation to the microphone sensitivity. The Nor1280 adaptor has the same function as the Nor1276, but with guard ring to ensure a minimum attenuation added to the microphone sensitivity.
The Nor1276 adaptor is included as a part of the Nor1204, 1/4″ preamplifier kit.
This adaptor has a true 1/2″ preamplifier configuration. This ensures that you can connect a 1/2″ microphone to a 1/4″ preamplifier with negliable loss in sensitivity. The unique construction of the adaptor extend the guard ring from the 1/4″ preamplifier to a true 1/2″ preamplifier with guard ring.
It is mainly used in application that requires a high degree of accuration, such as calibration laboratories and intensity probes etc.
For use with Preamplifier Nor1201 and Nor1206.
Special lengths may be ordered. See Nor1440.
Preamplifier extension cable Nor1408A comes with Lemo connectors to fit directly in the measurement chain. The contact pins are gold plated and the connector housing is protected with a special rubber sleeve. This protects the connectors in use from moisture, dirt and bumps. The Nor1408A replaces the Nor1408. The A version is similar to the 1408 but has in addition added threads on the outer shell of the female connector to fix the lock ring on a Nor1206 and Nor1209 preamplifier. The cable is a general purpose cable suited for all preamplifiers following the Lemo 1B standard developed by Norsonic, such as Nor1201, Nor1203, Nor1204, Nor1206 and Nor1209 as well as preamplifiers of other brands.
Standard lengths are 5, 10, 20, 30 and 50 metre. Special lengths on request. The /xx in the order code denotes the lenght of the cable.
This cable is designed for fixed installations in test chambers. It has the same pinout as a standard Nor1408 cable.
Norsonic cable drums are available in two different sizes. Both drums have a small reel attached to the main reel that holds one end of the cable, approximately 2 metres, needed for attaching the cable from the drum to the measuring equipment. The cable can easily be removed from the drum without disassembling it.
Norsonic cable drums are available in two different sizes. Both drums have a small reel attached to the main reel, that holds one end of the cable, approximately 2 metres, needed for attaching the cable from the drum to the measuring equipment. The cable can easily be removed from the drum without disassembling it.
Preamplifier cable Nor1410A comes with Lemo connectors to fit directly in the measurement chain. It features high quality connectors with gold plated contact pins. The Nor1410A replaces the Nor1410. The A version is similar to the 1410 but has in addition added threads on the outer shell of the female connector to fix the lock ring on a Nor1206 or Nor1209 preamplifier. The cable is a general purpose cable suited for all preamplifiers following the Lemo 1B standard developed by Norsonic, such as Nor1201, Nor1203, Nor1204, Nor1206 and Nor1209 as well as preamplifiers of other brands.
Standard length is 2 metre. For special length see Nor1408A.
Flat tape extension cable (0.5m) for door or window passage of preamplifier cables with Lemo connectors.
The cable is suited for all preamplifiers following the Lemo 1B standard developed by Norsonic, such as Nor1201, Nor1203, Nor1204, Nor1206 and Nor1209 as well as preamplifiers of other brands.
Having a length of 2 metres, this cable is a 3 mm thin and flexible cable with BNC connector in one end and a Lemo male in the other end. For connection of an electrical signal to a measuring instrument using Norsonic Lemo system.
The line input adaptor Nor1447 provides a BNC line connection to a ½” preamplifier such as Nor1201. The main application is for connecting an electrical signal to a microphone preamplifier. But it may also be used to connect a transducer like an accelerometer to the high impedance input of a microphone preamplifier or as a ”dummy microphone”. A built in screened capacitor in series with the line signal prevents the polarisation voltage from damaging the line signal source (Except from the Nor1447/S). The attenuation of the signal is small due to the design with use of a screened capacitor that is connected to the preamplifiers guard ring. The most popular version is the Nor1447/2 that has a capacitance equal to a ½” microphone. Other versions with other capacitance are available. Please note that all versions are for connection to a 1/2″ preamplifier. Each unit is individual calibrated with calibration certificate for the capacitance (Except from Nor1447/S).
The following versions are available:
Nor1447/S – Direct connetion without serial capacitor
Nor1447/L – Low input capacity version C=2pF or C=6.8pF
Nor1447/2 – Replaces a 1/2″ microphone load. C=18pF
Using the Nor1447 as Microphone Equivalent – ”Dummy microphone”
A microphone equivalent is mainly used to determine the electrical self noise of a sound level meter. The microphone is replaced by the microphone equivalent. As the microphone equivalent has impedance similar to that of the microphone cartridge, but no sensitivity to the acoustic field, the level displayed on the sound level meter will be the electrical self noise of the sound level meter including the preamplifier.
The capacitor used in the Nor1447 is a high quality type to minimise the microphone effect of the capacitor.
All units (except from /S and /L) are delivered with a BNC shortage plug included. The 1447/x with a BNC shortage plug connected equals to a microphone equivalent.
The method is not usable for measurement of the thermodynamic noise of the microphone cartridge.