(TM) Precision Microphone System User`s Manual
Contents
1. ACO Pacific Inc 2604 Read Ave Belmont CA 94002 USA Tel 650 595 8588 FAX 650 591 2891 e mail acopac acopacific com ACOustics Begins With ACO k u n KKKKAKKKKKKKKAKAKKAAKKKKKAKKKAAKAKKKAKKAKAKAKAKKKKKAAKKAKKAKKKKAKAKAAKKAKKAKKAKAKANAKAAKKAKKKAKAKAKKKKAKKKKKAKAAAKKAKKAKKKKKKKKAAKKAKKAKKAKKAKKAAKKAKKKKKAAKAKKKAKKAKKAAKAAN The ACOustical Interface PRECISION MICROPHONE SYSTEM User s Manual Figure 1 ACOustical Interface System SYSTEM OPERATION USERS MANUAL This manual describes the basic operaton of the ACOustical Interface System Installation system controls and the actual operation of the ACOustical Interface tm system are included The ACOustical Interface system has four major components a measurement microphone 1 4 1 2 and 1 Inch versions are available the companion microphone preamplifier the power supply and the optional G gain stage windscreen and optional PS9 110 VAC or PS29 220VAC AC adaptors Use of the SPL Calibrator may be found in the 511E manual INSTALLATION The microphone system has three main components the microphone capsule the preamplifier cable and microphone adaptor where applicable Preamplifier The 4012 preamplifier has two components The preamplifier body with end cap EC2 and the companion cable with mating connectors XLR or Lemo The CA4012 5 is terminated in a 5 pin Male XLR This2. Acoustic Signal Polarity A Reminder In some measurement applications such as loudspeaker testing knowing the absolute polarity of the acoustic wave is important The traditional polarized measurement microphone has a positive polarization voltage on the back plate This is an artifact of the positive plate anode voltage found in tube valve designs The output of the traditional measurement microphone preamplifier both tube and solid state is non inverting These designs are usually a cathode tubes or JFET source followers As a result of the positive polarization voltage positive going acoustical waves result in a negative going electrical signals from the microphone and preamplifier This does not affect the accuracy of the measurements but does need to be taken into account in some applications On the other hand Electret prepolarized microphones have a negative polarization voltage electrons stored in the electret material Positive going acoustic waves result in the electron charge being reduced on the backplate thus a positive going output voltage is seen Again the measurement accuracy is not affected It is convention for POLARIZED MEASUREMENT MICROPHONES on Non Inverting Preamps to output NEGATIVE GOING SIGNALS FOR POSITIVE GOING SOUND PRESSURE For ELECTRET MICROPHONES on Non Inverting Preamps POSITIVE GOING SOUND PRESSURE RESULTS IN POSITIVE GOING SIGNALS The preamps of ACO Pacific Bruel and Kjaer and others
3. 8588 Fax 650 591 2891 e mail acopac acopacific com ACOustics Begins With ACO 1998 ACO Pacific Inc All Rights Reserved
4. inch adaptor DO NOT OVERTIGHTEN 1 INCH MICROPHONES An AD0122 1 inch to 1 2 inch adaptor is required Slide the AD0122 1 Inch Mic to 1 2 inch preamp adaptor over the preamplifier from the microphone end and thread in place This is the ACO Pacific 4022 Preamp combination Mount the mic capsule on the adaptor preamp combination DO NOT OVERTIGHTEN The dust cap must be removed when making measurements MICROPHONE GRIDS DO NOT REMOVE It Is Not Necessary The grids of most ACO Pacific microphones are removable This is not necessary for most measurements The microphone is designed for use with the grid Removal will not give you better or higher or lower readings The FREE FIELD response curve supplied with Free Field capsules assumes the grid is on the microphone capsule Removing the grid does change the high frequency response If you must remove the grid do so with care It is very easy to crease the 2u thick diaphragm or even tear it In ALL cases DO NOT OVERTIGHTEN the grid or the microphone The fine threads of both make this very easy PS9200 OPERATION The PS9200 utilizes a standard L1604 9 Vdc Alkaline Transistor Radio Battery The Battery Compartment is located on the bottom of the case below the BNC cable connectors The Power Switchis located on the bottom front of the unit below the Preamp input connectors The Power Switch is a LOCKING TOGGLE TO Turn ON or to Turn OFF GENTLY PULL OUT ON THE HANDLE BEFORE TOGGLI
5. 4L7 has only A amp B markings Designate the remaining two channels C and D as you wish The Power Switchis located on the bottom front of the unit below the Preamp input connectors The Power Switch has a LOCKING TOGGLE TO Turn On GENTLY PULL OUT ON THE HANDLE BEFORE TOGGLING THE SWITCH UPWARDS ON A Flashing LED indicates power is applied FLASHING also indicates the battery or supply voltage is above 6 2 Vdc A STEADY LED indicates the battery voltage is low You will have about 1 2 hours with 1 preamp of useful battery life left when the LED is on STEADY Replace the battery as soon as possible You should not see a steady LED during normal AC Adaptor PS9 or PS29 operation TURN ON TIME 2 4 minutes The extended low frequency response of the microphones and the preamplifier result in long turn on times for the ACOustical Interface System Typically this will be about 2 4 minutes IMPORTANT THE PS9200 HAS BEEN DESIGNED TO REDUCE THE 200 Vdc POLARIZATION VOLTAGE WHEN NO PREAMPS ARE PLUGGED IN TO THE SUPPLY IT WILL TAKE AT LEAST1 2 MINUTES TO STABILIZE AFTER THE PREAMP IS INSTALLED YOU WILL NOT READ 200 Vdc ON PIN 3 OF THE SPARE XLR CONNECTOR THE OUTPUT RESISTANCE OF THE CIRCUIT IS 11 MEGOHMS THIS IS TO PROTECT YOU THE USER The typical DVM Digital Voltmeter has 10 MegOhms of input resistance creating a voltage divider You may read about 60 to 100 Vdc This is not an accurate reading CAUTION W
6. NG THE SWITCH Up is ON and Down is OFF INSTALLING BATTERY Not required for AC operation First TURN OFF the PS9200 Turn over the unit Slide open the compartment door and connect the battery to the polarized connector in the compartment Use caution DO NOT Reverse the Battery Connections If you have accidently left the unit turned on you will blow the 250 mA fast blow fuse inside the PS9200 Replace the door BATTERY LIFE FOR A SINGLE PREAMP OPERATION IS 50 HOURS TYPICAL As with all battery powered devices temperature type of battery and age of the battery effect operational battery life Battery life with the 4012HP higher current version is much less about 10 12 hours Battery life for the PS9250 is similarly reduced AC OPERATION 110 Vac PS9 220 Vac PS29 Plugging your PS9 or PS29 into the external power connection on the side of the PS9200 disconnects the battery removal of the battery is not necessary The PS9200 automatically disconnects the battery when external DC is supplied You do not need to install a battery for AC Only operation OPERATION With a 9 Vdc battery installed or an AC Adaptor PS9 or PS29 connected you are now ready to connect the microphone preamplifier and output BNC cables ATTACHING THE 4012 or similar Preamp Your BNC signal cable should then be attached to the BNC connector directly inline with the preamp cable The label designates these channels A and B Note the PS920
7. are Non Inverting Optional Eguipment SCI and SC2 Custom Storage Cases The SCI non locking and SC2 locking storage cases have die cut foam inserts designed specifically for the storage and transport of the PS9200 Microphones Preamps and their cables WSI windscreen PS9 or PS29 Adaptors Microphone Adaptors Spare Batteries and the 511E calibrator The SC1 is provided as part of the PS9200KIT The SC2 may be specified as an option WS1 3 Windscreen The WSI windscreen is designed to reduce wind noise in outdoor applications The material was selected to minimize attenuation of sound to beyond 20 kHz The WSI may also be used additional mechanical protection for the microphone It will protect the microphone diaphragm from stray particles oils and other materials and act as a bumber in the case of a mishap The WSI is included in the PS9200KIT WS7 7 Windscreen The WS7 windscreen was designed for higher velocity wind environments like thjose found in the desert of the Southwest US The WS1 is adequate for most applications DM2 Series of Dummy Microphones The DM2 Series of dummy microphones permits the connection of electrical signals to the input of the 4012 preamplifier The DM2 22 dummy microphone has a 22 pF coupling capacitor to simulate a typical 1 2 inch mic capsule For more information read the Dummy Microphone Users Manual Return to Home Page ACO Pacific Inc 2604 Read Ave Belmont CA 94002 USA 650 595
8. e is supplied in a reusable storage box 1 inch and 1 2 inch condenser microphones are supplied with a plastic protective cap 1 4 inch microphones may have a storage stand Save these accessories All ACO Pacific measurement microphones have an individual Birth Certificate The certificate provides actual measured sensitivity data and freguency response curves for the specific capsule RETAIN THIS CHART The plastic cap provided on some capsules protects the stored microphone from accumulation of dust and dirt on the diaphragm The cap should be stored in the microphone box as may the 1 4 inch mic stand INSTALLING THE MICROPHONE CAPSULE The microphone end of the 4012 preamplifier is protected by a machined metal cap EC2 This cap protects the preamplifier input from dust oil and physical damage when the microphone is not installed To remove simply unscrew the cap from the preamp body Save the preamp cap The cap may be stored in the microphone box with the microphone cap 1 2 INCH MICROPHONES Carefully install the selected microphone capsule on the face of the preamplifier DO NOT OVERTIGHTEN YOU MAY PERMANENTLY DAMAGE ANY PRECISION MIC BY EXCESSIVE FORCE FINGER TIGHT IS ADEQUATE 1 4 INCH MICROPHONES An AD0016 1 4 to 1 2 inch adaptor is required Place the AD0016 preamp adaptor on the face of the preamp The ACO Pacific 4016 Preamp is this combination Carefully place the 1 4 inch mic capsule on the end of the 1 4
9. hile the input to the 4012 Preamp is protected against electrical discharge use care when installing and removing the microphone If you accidently touch the center pin of the preamp to the shield or ground the 200 Vdc polarization charge will be removed and take about 2 minutes to restabilize A slow increase in the sensitivity will be noticed as the voltage returns G Gain Option The G option provides two independent fixed gain or buffer stages Factory installed the gain is preset to order by the factory Standard gains are 20 dB and 40 dB Switches for each channel are located on the back of the PS9200 next to the BNC signal output connectors A color dot or label next to the switch indicates the preset gain of the individual channel In the Direct position signals from the 4012 or other preamp are directly fed to the BNC through the internal decoupling cap The maximum signal limits in this mode are determined by the preamplifier and the preamp 28 Vdc operating voltage 50 Vdc with the PS9250 The maximum output voltage swing of the G option is determined by the DC supply voltage of the PS9 PS29 This is typically 3 3 Vrms for a 13 5 Vdc source NOTE Operation from the internal 9Vdc battery is not recommended The ACOustical Interface and microphones are precision measurement equipment Designed for the rigors of field use they will last for many years of accurate stable measurements if properly treated and maintained
10. is mates with the standard PS9200 family of power supplies The CA4012 7L is terminated in a 7 pin Male Lemo connector The CA4012 L7 pinout is compatible with the PS9200L7 2 channel and PS9204L7 channel power supplies It is also compatible with Hewlett Packard Norsonic and Bruel and Kjaer instruments equipped with the mating connector 4016 1 4 Inch preamplifier consists of the 4012 and companion cable and the AD0016 1 4 to 1 2 Inch adaptor 4022 1 Inch preamplifier consists of the 4012 and companion cable and the AD0122 1 Inch to 1 2 Inch adaptor Prepolarized Electret Microphones CAUTION ELECTRET Prepolarized MIC CAPSULES e g ACO Pacific s MK224 7052S 7051S or B amp K 4155 require the special CA4012 5E CA4012L7E cable designated by yellow or black marking on the XLR Lemo end This cable has the 200 Vdc polarization conection removed and is the polarizaton connection at the preamp is grounded Never place an Electret Capsule on a standard preamp cable This will cause temporary and possibly permanent loss of sensitivity The preamplifier body is detachable from the CA4012XX cable This makes for easier installation of cables and allows the preamp cable to be permanently installed The preamplifier body may be detached for safe storage testing or replacement Longer CA4012 cables or CE4012 extension cables are available on special order ATTACH THE CA4012 XX TO THE PREAMP Microphone Installation The microphon
Download Pdf Manuals
Related Search