Electro-Voice PL78 User's Manual
Contents
1. SPECIFICATIONS Generating Element Electret condenser Frequency Response 50 Hz 18 kHz Polar Pattern Cardioid Impedance 150 ohms balanced Output Level 49 0 dB 0 dB 1 mW 10 dynes cm 2 5 mv Pascal 1 kHz Dynamic Range 122 dB Equivalent Noise Level Less than 30 dB 0 dB 0002 dynes crn A weighted Switch On off Power Supply 4 5 volt battery not included or 24 to 48 volt phantom supply Current Drain 3 5 mA Recommended Batteries Alkaline Eveready No 523 Mallory PX 21 Pop Filter Built in Acoustifoam filter Grille Screen Material Memraflex tempered spring steel Case Material Diecast zinc and aluminum Finish Snow gray and charcoal Dimensions 201 9 mm 7 95 in long 48 3 mm 1 90 in maximum diameter Weight 288 grams 10 16 oz Accessories Furnished 301 stand clamp Zippered viny carrying pouch Useable response range DESCRIPTION The Electro Voice PL78 is a Single D cardioid low impedance electret condenser microphone featuring smooth frequency response in a rugged diecast case The PL78 can be powered using an interna battery or any phantom power source be tween 24 and 48 volts An on off switch is provided to mute the microphone in either battery or phantom power and in the battery mode open the power connection to con serve battery life APPLICATIONS The PL78 is designed to provide superior gain before feedback in live entertainment2. 4 j WENN eyii Co LP are EDMEE Yall bdb AEREE a g gaasis F FFE g FREQUENCY N HERTZ FIGURE 2 Frequency Responses FIGURE 3 Polar Response bass pickup at a distance of 24 inches or more By moving the PL78 to within a few inches of the instrument bass response will be increased CAUTION NOTES With the sound source lips closer than 4 inches bass response is increased dramatically as shown in Figures 2A and The resulting signal may be beyond the input range of your mixer or amplifier which can cause distortion In these cases an in line attenuator or pad installed between the microphone and the mixer will eliminate the distortion MAINTENANCE INSTRUCTIONS You have purchased one of the finest elec tret condenser microphones available A little care will allow you continued use of this precision instrument for many years Your electret condenser microphone should not be left in the open sun or other hot environments where temperatures may approach or exceed 54 4 C 130 F for any period of time Following this sug gestion will prolong the life of the generating element lf you fee your unit is malfunctioning have it examined and repaired only by an Electro Voice authorized repair service station POWERING THE PL78 Unlike normal condenser microphones the electret condenser does not need a polariz ing voltage because a permanent charge is captured in th
3. e diaphragm material However a small voltage with low current drain is necessary to power the FET im pedance converter which must be used to lower the extremely high impedance of the electret head You may gain access to the battery compartment by unscrewing and pulling away the rear sleeve of the microphone exposing the battery clips see Figure 5 A 4 e volt alkaline battery should be inserted being sure to follow the polariza tion label With the very smali current drain of 3 5 mA it is common to have 150 hours or more of battery life An Alkaline type battery is recommended because of its much greater shelf life and less likelihood of leakage A noticeable reduction in output gradually occures well before complete failure usually allowing replacement of the battery without program interruption The PL78 may also be operated from any phantom power source between 24 and 48 volts The microphone can be operated from a phantom supply with a battery installed without any affect on microphone performance ARCHITECTS AND ENGINEERS SPECIFICATIONS The microphone shall be a Single D cardioid electret condenser type with frequency response of 50 to 18 000 Hz The microphone shall have an 150 ohm balanced output with an output level of 49 0 dB 0 dB 1 mW 10 dynes cm and 2 5 mv Pascal 1 kHz The microphone shall have an electret condenser generating element whose output shall not be appreciably affected by temperat
4. other than specified conditions Repair by other than Electro Voice or its authorized service agencies will void this guarantee For repair information and service locations please write Service Dept Electro Voice Inc 600 Cecil Street Buchanan Michigan 49107 Phone 616 695 6831 or Electro Voice West 8234 Doe Avenue P O Box 3297 Visalia CA 93277 Phone 209 651 7777 Electro Voice also maintains complete facilities for non warranty service of EV products Specifications subject to change without notice FIGURE 4 Schematic FIGURE 5 Battery Replacement RED PIN 2 3 PIN AUDIO CONNECTOR BLUE SHIELD PIN 3 PIN 1 TIP CONNECTION CONNECTION FIGURE 6 3 Pin Connector amp 14 Phone Plug Wiring Connections ELECTRO VOICE INC 600 Cecil Street Buchanan Michigan 49107 MANUFACTURING PLANTS AT E BUCHANAN MI E NEWPORT TN E SEVIERVILLE TN E REDMOND WA E GANANOQUE ONT Gulton Industries Inc 1984 w Litho In U S A e gulon ni any Part Number 530447 442
5. und reinforcement system is sustained by reflection of sound into the mircrophone As the level of the voice at the microphone increases the microphone s signa to the amplifier is in creased For a constant volume of sound from the system the amplifier gain setting must be proportionately reduced This results in a reduction of the system s sensitivity to reflected sound hence a reduction of the tendency to feedback The variable low frequency response of the PL78 provides a further feedback reducing advantage in close talking applications At Y4 inch low frequency response is greatly enhanced while response to distant sound as from sound system loudspeakers is unaf fected The result is a reduced tendency to feedback over and above that provided by the cardioid directional characteristic alone In short system sensitivity reduction because of close working added to the advantage resulting from the bass boosting low frequency characteristic of the PL78 makes this instrument an exceptionally effective tool for stage and nightclub use 3 For musical pickup the variable bass response can be utilized to achieve clean 48 3 mm 1 90 In PT SER TTT TT Enh TTT TT ET En ann TETRAN s Za TS A AA L A TLITI METALS AEAN BE a E 88x88 z E sssesss g FFF g Normal 1 4 Working Conditions COM oot COO ok Kee Comic eee eerie COTA E T COCO Alii IN
6. ure ex tremes from 17 8 C 0 F to 54 4 C 130 F and or by humidity extremes An on off switch shall be provided The case shall be zinc diecast with an aluminum battery compartment cover The finish will be non reflecting snow gray and charcoal paint Dimensions shall be 201 9 mm 7 95 in long not including cable con nector with shank diameter of 25 4 mm 1 00 in Net weight including battery but less cable shall be 288 grams 10 16 oz The Electro Voice Mode 301 stand clamp and a zippered vinyl carrying pouch shall be furnished The Electro Voice Mode PL78 is specified WARRANTY Limited Electro Voice PL78 Microphones are guaranteed unconditionally against maliunc tion from any cause for a period of two years from date of original purchase Also these microphones are guaranteed without time limit against malfunction in the acoustic system due to defects in workmanship and materials If such malfunction occurs microphone will be repaired or replaced at our option without charge for materials or labor if delivered prepaid to the proper Electro Voice service facility Unit will be returned prepaid Any active electronics in corporated in a microphone are guaranteed for three years from date of original pur chase against such malfunction Warranty does not cover finish appearance items cable cable connectors or switches Defect guarantee does not cover maliunction due to abuse or operation at
7. use where sound is reflected into the microphone The PL78 minimizes feedback by emphasizing a smooth peak free fre quency response employing a cardioid polar pattern and finally transducer element positioning The placement of the condenser element close to the front of the microphone insures the highest ratio of gain before feedback Electronic tailoring is used to con trol the suDsequent increase of bass eneray Feedback problems can be further reduced by close microphone placement to the per former that yields a significant reduction in undesirable background and reflected sound USING THE VARIABLE LOW FREQUENCY RESPONSE The PL78 low frequency response varies with the distance from the source to the microphone as shown in the resonse curve Figure 2 Maximum bass response is pro duced in close up use with the microphone Ye inch from the sound source Figure 2A Minimum bass response is experienced at distances greater than 24 inches Figure 2C Electro Voice g gultan company Model FL 8 condenser Cardioid Vocal Microphone Useful special effects can be created by an imaginative application of the variable low frequency response 1 By varying the distance between the mouth and the microphone a wide range of tonal variations are possible Generally the greater working distances provide a natural more intelligibile output while the closer pro vide a deeper more robust sound 2 Feedback in a so
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