Shure m268n owners manual

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Extracted text from shure m268n owners manual (Ocr-read)

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2 Outputs IMPEDANCE OUTPUT Designed for Use W ith Actual (Internal) Output Clipping Level Low Imp Mic Any low imp (19 to 600 ) mic circuit 120 ±22 dB (10 0 m V) High Imp Mic Unbal 10 to 50 k mic circuit 5 k +4.5 dBV (1.7 V) Aux 10 k or greater unbalanced high-level cir- cuits 2.5 k 18 dBV (7.9 V) Mix Bus 3.3 k 3.3 k ±8 dBV (0.4 V) Noise Equivalent Input Noise: ±128 dBV (low impedance mic 150 - 300-20,000 Hz) at full gain Equivalent Input Hum and Noise: ±125 dBV (low impedance mic 150 - 20-20,000 Hz) at full gain Output Noise: ±90 dBV (master control down). ±65 dBV (maste r u p), (inpu t control s d own , 3 00-20,00 0 H z) Output Hum a nd N oise : ±8 2 d BV ( maste r d own) , ± 60 dBV (master up) (inpu t c ontrol s d own , 2 0-20,00 0 H z) Common Mode Rejection 65 dB minimum with 100 mV input at 100 Hz Control Interaction Less than 1 dB with any control combination Phase All microphone inputs and outputs in phase; tips of high-impedance inputs and mix bus jack in phase with pin 3; aux input in phase with aux outputs and pin 2 Phantom Power 30 Vdc open circuit, 3.3 k series resistance Operating V oltage 120 or 240 volts +10%, 50/60 Hz, 5W , supplied wired for 120 V ac operation (see Service section for 240 V ac operation) Temperature Range Operating: ±18 o to 57 o C (0 o to 135 o F) Storage: ±29 o to 74 oC (±20 o to 165 o F)Dimensions See Figure 1. 309 mm (12 5/32 in.) 68.8mm(2 23/32 in.) 6.3 mm(1/4 in. ) 229 mm(9 in.) FIGURE 1 Weight Net: 1.8 kg (4 lb 1 oz) Packaged: 2.8 kg (6 lb 1 oz) Certifications Listed by Underwriters' Laboratories, Inc., and listed by Canadian Standards Association as Certified CONTROLS AND CONNECT ORS WARNING This apparatus must be earthed (grounded)! The M268 power supply is energized when the unit is connected to an ac source; disconnect mains (power) plug from supply when not in use. Inputs A maximu m o f fou r low - a nd fou r h igh-impedanc e d ynamic, ribbon or condense r m icrophone s c an b e c onnecte d to r ecep- tacles marked INPUT 1, INPUT 2, INPUT 3, and INPUT 4. The input s a re d esigne d for low-impedanc e m icrophone s w ith 19 to 600 impedance, or high-impedance microphones. Both low - a nd h igh-impedance m icrophone s c an b e u sed s i- multaneously. Crysta l or cerami c m icrophone s a re n ot recom- mended. The input receptacles are professional three-pin XLR Audio-typ e c onnectors , a nd 1/4 phon e jacks . S ee Fig- ure 2 for low- and high-impedance connections to inputs. Note that some condenser microphones produce very high output signal s w hic h m ay o verloa d the input s o f m an y m ixers; the M268's feedback-type active gain controls virtually elimi- nate the n eed for in-lin e a ttenuator s to c ompensat e f or these ªhotº microphones. 1 2 3 MICROPHONEMIXER INPUT SHIELD LOW IMPEDANCE(BALANCED LINE) MICROPHONE MIXER INPUT SHIELD HIGH IMPEDANCE SHIELD SHIELD LOW IMPEDANCE OUTPUT (BALANCED LINE) HIGH IMPEDANCE OUTPUT MICROPHONE INPUT CONNECTIONS MICROPHONE OUTPUT PLUG CONNECTIONS 1 23 FIGURE 2

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3 The rear-panel phone jack marked AUX IN will accept output from a high-impedance, high-level source such as a tape recorder or am-fm tuner. Outputs The connectors marked LOW IMP OUTPUT and HI IMP OUTPUT are the ªmixedº output of all the input sources and are designed to work into a balanced (low impedance only) or unbalanced 150- to 600- microphone line or into a high-impedance unbalanced amplifier or tape recorder microphone input. The output connectors are a profes- sional three-pin XLR audio connector and a 1/4phone jack. See Figure 2 for output connector configurations. The phone and phono jacks marked AUX OUT are high- impedance, high-level, unbalanced outputs designed pri - marily to feed a power amplifier requiring 0.1 to 2 volts in - put, or the auxiliary or tuner input of an amplifier or tape recorder. Interconnecting cables should be limited to a maximum length of about 25m (75 ft). Controls In additio n t o the p owe r O N/OF F s witc h ( an a djacen t LED indicates power-on in a c o peration) , the f ron t p ane l contains five individua l inpu t gain c ontrol s d esignate d 1 t hroug h 4 a nd AUX, and a M ASTE R g ain c ontrol for the t ota l progra m o ut- put. N ote t ha t the i npu t c onnectors are l ocate d o n t he r ear panel directl y b ehin d t heir correspondin g g ain c ontrols. The M268 has feedback-type active gain controls for lower noise and greater dynamic range. In general, the in - dividual gain control should be set to 5 or higher (clock- wise), and the MASTER control adjusted for the required output. If overload distortion (clipping) occurs when using high-level sources, reduce the individual gain control set - tings. Unused individual gain controls should be kept at the minimum setting (counterclockwise). Mix Bus The rea r p ane l M IX B US p hon o jac k facilitate s the ª stack- ingº of mixers to obtain additional inputs without using any of the M 26 8 inputs . C onnectin g the m ix b uses of two M 268s, for instance , d irectl y c onnect s t hei r m ixin g s ystems , p rovid- ing two independen t m aste r control s a nd two isolate d o utput amplifiers with 1 0 individuall y c ontrolle d inputs . Note tha t the gain will be r educe d b y 6 d B, but nois e s pecification s a re n ot adversely affecte d b y this interconnection . M ix b us intercon- nections can a lso b e m ad e w ith o the r S hur e m ixer s s uc h a s the M26 7 a nd t he M 67. Phantom Power The M268 provides power for condenser microphones such as the Shure SM81 and SM85. The rear-panel PHANTOM OFF/ON switch controls the application of phantom voltage to all low-impedance inputs. With the PHANTOM switch on, +30 Vdc is applied to pins 2 and 3 of each LO IMP connector. Series current-limiting resis- tance is 3.3 k for each input. When using other condens - er microphones with the M268, verify that the voltage and resistance are compatible. Balanced low-impedance microphones (dynamic, rib- bon, self-powered condensers) can be used in combina - tion with phantom-powered condenser microphones. IMPORTANT: Do not turn on the PHANT OM switch when using unbalanced low-impedance microphones: objec- tionable hum will result. Turn off the PHANTOM switch when condenser microphones are not being used. Use only high-quality cable, as intermittent shorts be- tween broken shied wires and balanced conductors will cause of fensive noise transients in the system. ACCESSORIES The Model A268R Rack Panel Kit consists of a 483 mm x 89 mm (19 in. x 3 1/2 in.) precut rack panel and necessary hardware for rack mounting the M268 in a standard 483 mm (19 in.) rack panel. The Model RKC169 Rack Panel Bracket Kit enables users of the Shure A68R Rack Panel Kit (originally de- signed for the Shure M67 and M68 Mixers) to rack-mount the M268 with the A68R. SERVICE WARNING Voltages in this equipment are hazardous. Refer servicing to qualified service personnel. Operation at 210-250 V ac The M268 is supplied wired for operation at 105-125 Vac. To rewire the M268 for operation at 210-250 V ac, pro - ceed as follows: 1. Disconnect the M268 from the ac line 2. Remove end caps and cover . 3. Locate Power Transformer T106 at right center of printed circuit board. Remove two jumpers between holes marked ª120V ONL Y.º Add jumper between holes marked ª230V ONL Yº at right of T206. 4. Replace ac connector with one designed for 210-250 Va c source. If M268 is to be used outside U.S. and Can - ada, local regulations may require replacing line cord with one having wire insulation colors as follows: ªLiveº or ªHotºNeutral Earth or Ground U.S., Canada Black White Green Europe Brown Blue Green/ Yellow 5. Replace Fuse F 10 1 ( presentl y 0 .1A , 2 50V , slow-blow ) w ith 0.05A, 250V, time lag unit (Shure 80C380, Schurter 034.3104) using supplied fuse clips (Shure 80A8008, Schurter O G 7 51.0052). 6. Replace cover and end caps. Affix new label to rear panel to reflect new operating voltage range.