Bogen BOGEN M300 Stereo Amplifier User Manual
Contents
1. Ge M Class Front Panel 1 Status Indicators The Status LED is a multi purpose indicator that lights in three colors to show status One for each channel e Green Amplifier is on and operating normally e Amber Amplifier is in low power consumption Sleep Mode e Red Amplifier has protected itself due to a fault condition 2 Signal Indicators Illuminates green when signal is present at the input One for each channel 3 Clip Limit Indicators This indicator illuminates amber when there are excessive signal levels or very low impedance output loads A built in Clip Limiting circuit activates and reduces input signal levels when output distortion exceeds a few per cent or when the output load draws too much current One for each channel 4 Power Switch Circuit Breaker Controls AC power to the amplifier and also works as a circuit breaker If the circuit breaker trips push it to the OFF position O and then to the ON position 5 Fan Grilles Removable fan grilles are provided to allow access to the dust filters for cleaning 6 Volume Controls Detented 40 position knobs are recessed for protection from mechanical damage One for each channe2. 9 Output Feeds eiie etenim e di Pe EIER 9 Modes ot ron en t en a e eer eor ei ee bo end 9 10 Stereo Mode tenis tnnt ihe eia ba FRE 9 TOV Mono ModE erae tret tenes esent 10 Dual Mono Mode 10 Audio Buses arivinta iiiar iisti 10 Modules 11 Standard Input Module netten eee tette toten 11 Standard Input Module Priority Jumper 11 Standard Input Module Gain Switches 11 Other Input Modules ttt teer i 11 Module Priority meet ttt tinis 11 Module Controls anne etai ee 11 APPLICATIONS 2u 220r0200000020000000000002000000000000000000nnn0nnnnnnnssnnnsnnnsnnnsnnnssannnnne 12 13 5 1 14 SPECIFICATIONS 15 Introduction Bogen s M Class amplifiers deliver on what professional sound installers need most Flexibility Power and Reliability Flexibility Power The M Class allows for the installation of up to 2 input modules accepting inputs from microphones telephone systems stereo sources mono sources or daisy chaining of amplifiers Each M Class model comes standard with a single professional quality stereo high impedance balanced input module The M Class has three operating modes to meet diffe
3. input shorted to ground G The unbalanced signal s shield I wire is connected to the input module s ground and the signal Zu Dem 3 hot wire is connected to the terminal Since unbalanced mee connections do not provide the same amount of noise immu nity that a balanced connection does the connection distances should be made as short as possible Controls amp Connectors Level Controls The front mounted level controls act differently depending on the mode of operation In the stereo mode each level control determines the volume of the corresponding amplifier channel as in a typical amplifier the 70V Mono and Dual Mono modes the controls have a different function and determine the mix of the signal levels from the different input modules input modules can be assigned to either the A or B chan nel by the jumpers on the module The front level controls determine the mix of the two input module signals They do not control the volume level of each amplifier in these modes Essentially the volume level of both amp channels is fixed at maximum and the overall level of the mixed input module signals determine the output volume level To increase the overall volume of the ampli fier output turn up both front panel controls by the same amount This increases the signal level of each mod ule s input into the amplifier while keeping the mix the same Similarly turn down both controls to the same knob position to reduc
4. CHANNEL B assigned to their respectively labeled Sl o s a audio buses SJ PF Standard Input Module Priority Jumper B GEN The input module that comes stan O The M Class is shipped with one input module pre installed The module pro vides 2 high impedance balanced low noise inputs but can be replaced by O CHANNEL GAIN 0 dB X1 Gain Position MUTING 18 dB 8 other modules if desired input s Gain Position CHANNEDR dard and pre installed with the M Class differs in priority capability from other Bogen input modules The module has a priority jumper that can set it to be muted by any other modules installed or to never mute Since it is incapable of muting other modules it is always the lowest priority module When signaled to mute by anoth er module it will reduce the level of both channel s input signals by the amount set by the ducking control DUCK When the mute is released the module will fade the input signal levels back to the previous level When set to No Mute it does not respond to muting from other modules and is therefore always available for use in mixing applications The module is factory set to be muted by any other module The module will have to be removed to change this setting Stand
5. DC level at signal input Load impedance too low Amplifier speaker output is short circuited Amplifier too hot check for proper ventilation clearances Poor electrical connections at input Input cable routed near AC cables power transformer or other EMI radiating devices Electrically noisy devices operating on the same AC circuit Poor equipment grounding Ensure that all AC safety grounds are connected Make sure that all components in audio chain are tied to the same ground 14 Power Output 70V Mono 1200W 4 ohms 900W 5 5 ohms 600W 8 ohms 4 ohm 600W per channel 450W per channel 300W per channel 8 ohm 400W per channel 300W per channel 200W per channel Input Sensitivity At Backplane Connector or using Standard Input Module incl Module has Gain of 1 S N Ratio 20K BW 109 dB ref 8 ohms FP 106 dB ref 8 ohms 103 dB ref 8 ohms FP 1 161V for 600W 4 ohms 1 010V for 450W 4 ohms 0 840V for 300W 4 ohms Product Weight 46 Ib 44 Ib 41 Ib Connectors Power 20A line cord 15A line cord 15A line cord Input 2 new Bogen std 12 pin connector modules RCA input Output 5 pin touch proof Barrier Strip RCA Pre amp Post EQ Output Frequency Response 1 watt 20 20 kHz 0 25 dB Output Regulation 1 kHz direct 0 5 dB 8 ohms Indeators Status On Protect Sleep Clip Limit Signal RE DC Low frequency Thermal Low Impedance Circuit Breaker Short Circuit B
6. or Dual Mono modes In these modes the inputs and front panel controls form a 2 1 mixer Connect the Effects Loop Out to the input of the external signal processing equipment Connect EFFECTS LOOP OUT IN the Effects Loop In to the output of the external signal processing equipment Inserting an RCA jack into the Effects Loop In connector will automatically disconnect the input module signals from the power amp stage so it can be routed through the external equipment Removing the jack from the Effects Loop In connector will reestablish the direct connection of the input modules to the power amp stage The Effects Loop signals are quasi balanced which means that they are intended for use with unbalanced equipment but will improve the noise immunity However it is still a good practice to keep these connections as short as pos sible Output Feeds Two different output feeds are provided that can supply signal to other amplifiers and audio equipment Both outputs are designed to feed high impedance unbalanced inputs of external equipment The outputs are also quasi balanced for better noise immunity OUTPUT FEEDS PREEQ POSTEQ but connection lengths for these outputs should still be kept as short as possible The Pre EQ Output Feed provides the signal before any external signal processing affects it The Post EQ Output Feed provides a signal that has been affected by the external signal processing equipment and lo cut filter De
7. reducing channel A volume Putting the control at the center of rotation allows equal and maximum volume from both channels Lo Cut Switch CHANNEL BALANCE The M Class amplifier is a direct coupled amplifier which means that there are no out put transformers used to deliver the 70V audio to the speakers Because of this the M Class amplifier has a Flat frequency response below 20 Hz This extended low fre quency operation can be troublesome for some transformer coupled speakers typical ly used in 70V audio systems The relatively inexpensive transformers used in these speakers cannot handle frequencies much below 60 Hz When frequencies lower than this are applied to these speaker s transformers they can saturate causing distortion and high instantaneous power consumption The Lo Cut filter allows a low frequency roll off to be introduced into the output signal preventing the speak ers from receiving too much low frequency content The 65 Hz position should be used for all transformer cou pled cone type speakers The higher frequency roll off of 125 Hz provides an extra level of safety for horn speakers Some horn speakers can be adversely affected by frequencies below 120 Hz since they are designed to reproduce higher frequency signals Effects Loop The effects loop connectors act as an insertion point for outboard signal processing equipment when the M Class is operating in either the 70V Mono
8. Both outputs are designed to feed high impedance unbalanced inputs of external equipment The Pre EQ Output Feed provides a signal before any external signal processing The Post EQ Output Feed provides a signal that has been affect ed by the external signal processing equipment and the lo cut filter 7 Operational Mode Selector The M Class amplifer has 3 distinct modes of operation Stereo 70V Mono Dual Mono that are designed to provide a wide range of application coverage For a description of the different modes see the Operation sec tion of this manual 8 Fan Exhausts Two independent variable speed cooling fans respond as needed to keep the amplifier cool and reduce dust build up 9 70V Mono Speaker Output For 70V constant voltage speaker systems Provides a single channel of amplification 10 Chassis Ground Provides convenient access to earth ground 11 Lo Cut Switch Select a low frequency roll off of 65 Hz or 125 Hz for transformer coupled and horn speakers Flat position allows full low frequency performance 12 Module Bay Accepts one or two Bogen input modules one module included with amplifier Installation Front Casting Notches Snap in tab Snap Slots Installation Components 1 Rack Ears Prior to installing the amplifier you will need to attach the installation rack ears if you intend to install the ampli fier in a rack and complete the setup process Remove the 6 f
9. M Class Amplifier M300 M450 amp M600 Models Installation and Use Manual 2001 B ical Communications Inc All rights reserved 54 2037 0210 Notice Every effort was made to ensure that the information in this guide was complete and accurate at the time of printing However information is subject to change Important Safety Information WARNING To Reduce The Risk of Fire Or Electric Shock Do Not Expose This Apparatus To Rain Or Moisture Always follow these basic safety precautions when installing and using the unit Soy UT m aN 10 11 12 13 Read these instructions Keep these instructions Heed all warnings Follow all instructions Do not use this apparatus near water Clean only with dry cloth DO NOT block any ventilation openings Install in accor dance with the manufacturer s instructions Do not install near any heat sources such as radiators heat registers stoves or other apparatus including amplifiers that produce heat Do not defeat the safety purpose of the polarized or grounding type plug A polarized plug has two blades with one wider than the other A grounding type plug has two blades and a third grounding prong The wide blade or the third prong are provided for your safety If the provided plug does not fit into your outlet consult an electrician for replacement of the obsolete outlet Protect the power cord from being walked on or pinched particularly at plu
10. Priority 1 BRG1R Bus B only Priority 2 Mode of Operation 70V Mono or Dual Mono Amplifier Adjustments Volume of local departure gate MIC is adjusted by the A Level Control Global music mes sage source is adjusted by the B Level Control Set Lo Cut or Channel Balance depending on mode of operation Module Adjustments Adjust Gain to make each sources input similar Adjust Bass amp Treble where applicable to your preference Adjust Ducking on BRG1R for desired level Adjust Gate control on MIC1X for optimum paging oper ation Application 4 2 mono zones low impedance speakers telephone paging and background music Zones have significantly different volume levels Background music plays through the system when no page is being made One zone is low volume while the other is high volume During a telephone page the background music mutes to a predetermined level and the telephone page is heard at correct volume level for each zone When the page is complete the background music fades back to its previous level Module Bus Assignment Priority Setting TEL1S Bus A only Priority 1 MAX1R Bus B only Priority 2 Mode of Operation Dual Mono Amplifier Adjustments Volume of the telephone page is adjusted by the A Level Control Background music level is adjusted by the B Level Control Set the Lo Cut switch to Flat or 65 Hz Channel Balance control on rear of ampli fier adjusts the volume level of one speaker zone o
11. ace 4 Installation Ventilation The M Class was designed to be placed on a table or rack mounted When rack mounted the amplifiers can be stacked one on top of the other for maximum use of the rack An open air space of at least 4 must be provided at the front air intakes of the amplifier and the rear exhaust must have at least a 4 gap from any obstructions to ensure adequate cooling This applies to both rack and table mounted amplifiers Care should also be taken to ensure that the front intake air is not considerably warmer than the ambient air temperature Mount the amplifiers low in the rack so that heat dissipation from other equipment does not warm the amplifier s intake air Rack Mounting Rack ears are included with the amplifier to allow mounting in 19 racks Attach the rack ears as shown in the Installation Components section lf any feet have been attached to the bottom of the amplifier remove them Load the amplifier into the rack and secure it to the rack with appropriate hardware not included Rear Rack Mounting For greater rear support when rack mounting an M Class amplifier the RPK86 Rack Mounting Kit not included can be attached to the rear of the amplifier by following the steps below 1 Remove and save the three cover screws from the chassis of the amplifier Rear of Amplifier 2 Position the rack attachment as shown 3 Replace and tighten the three cover screws to secur
12. ard Input Module Gain Switches A separate gain switch for each input channel is included in the module that comes pre installed with the ampli fier The module is factory set for 0 dB gain Set each switch for the channel s desired gain either 0 dB X1 or 18 dB X8 Other Input Modules Various input modules can be installed in the M Class amplifier Refer to the instructions that come with each module for specific connection and setup information The module jumpers must be set prior to installing the module Module Priority Bogen input modules allow for up to 4 levels of priority Each module except the included input module which comes standard with the amplifier can both be muted by higher priority modules and mute lower priority mod ules The priority level of the module is set by the position of 2 jumpers on each module Note Even though 4 priority levels are available on the Bogen input modules only two levels can be used with the M Class since it only accepts 2 modules It does not matter which priority level is set on the module only that the intended higher priority module be set to some priority level that is higher than the intended lower priority module However Bogen recommends using Priority Level 1 the highest available for the higher priority module and Priority Level 2 for the lower priority module Module Controls Each input module type has a number of controls such as Gain Bass and Treble These control
13. ckage Contents ssssssscssscsscssscnscnsscnecnecsseseecsseesecnseuceusecucueenesseseueecseeueecnscneecnesneesseees 1 PANEL DESCRIPTIONS 2 1 0 21 1 4 2 enses satus sensa 2 3 M Class Front Panel 2 M Class Rear Panel UERDN ES 3 INSTALLATION 4 6 Installation COMPONENES 4 Ventilation Rack Mounting Rear Rack Mounting 5 Hep 5 Module Stal ciertas EENAA EAEE 6 lee n 7 SPEAKErS P 7 Low Impedance Speaker Connections sse 7 Earth Ground eir iie eu eese 7 70V Transformer Coupled Speakers sse 7 Standard Input 7 Balanced Input Connections tetti iie tto nie teie rie aieo ies nennt 7 Unbalanced Input Connections essent 7 OPERATION Controls Connect rs n onion Level G ntrols sense red Dn n F e EE Oe Hen cana Sleep Mode Defeat Channel Balarice decente itio esie La Cut S WIECH 8 Effects LOOP
14. des back to its previous level Bus Assignment Priority Setting MIC1X Bus A amp B Priority 1 BAL2S Not assignable MUTE Included standard with M Class amplifiers Mode of Operation Stereo Amplifier Adjustments Stereo music program wired to BAL2S inputs Each stereo channel volume is controlled by the associated front level control Microphone level is also affected by changes in these level controls but is to be main ly set by the Gain control on the MIC1X module Not applicable in stereo mode Module Adjustments Adjust Gain of MIC1X to desired paging level Adjust Bass amp Treble of MIC1X module to appro priate level Adjust Gate controls of MIC1X for optimum paging control Adjust ducking control on BAL2S for desired mute level 12 Application 3 Global music message buffered and distributed to multiple amps with local override input for each amplifier Similar to the paging situation found at airport departure gates global music messages play when no local page is present During local page from departure gate microphone music message mutes to predetermined level and page is heard only in local area When local page is complete global music message fades back to previous level During local zone page global music message mutes only in local area then fades back Buffered global music mes sage signal is unaffected by local paging condition Module Bus Assignment Priority Setting MIC1X Bus A only
15. e amount of distortion in the output signal and reduces input levels as the amplifier approaches clipping Back Slope Bogen s unique voltage stabilization circuitry regulates the AC energy supplied to the power toroid This improves both system performance and reliability despite varying AC supply conditions An energy conserving sleep mode defeatable with instant on return signal operation reduces wasted heat production in paging systems with intermittent use In addition large output heatsinks and dual independently controlled high output variable speed fans provide superior cooling and quiet operation while reducing dust accumulation Bogen s M Class amplifiers are enclosed in a heavy gauge steel chassis which prevents mechanical damage to the unit s internal components even if the unit is subjected to rough handling and excessive portable installa tions The control knobs are located in a recessed section of the cast aluminum front panel to reduce the like lihood of mishandling and damage The angled design of the amplifier s front panel allows easy finger access to the front knob cover when the amplifiers are stacked tightly in a rack Package Contents M Class Amplifier 2 Rack Ears 2 Filters and Grilles Instruction Manual Control Knob Cover Balanced Input Module pre installed 4 Rubber Feet amp Screws status signal clip limit M CLASS AMPLIFIER
16. e the overall output volume from the amplifier Sleep Mode Defeat The M Class amplifier includes a sleep mode feature that greatly reduces the power consumption of the amplifier after it has been idle for more than 3 minutes Any audio activity present at the input will wake the amplifier up instantaneously so that there is no loss of audio A sleep mode switch located in the upper right hand corner of the module bay can be set to activate or deactivate this feature using a thin flat bladed screwdriver If a module is inserted in the right bay turn off the power and remove the module before proceeding If the sleep feature is desired make sure the switch is in the down position If the sleep feature is not desired make sure the switch is in the up position 5 Sleep Mode Channel Balance Channel Balance only works in the Dual Mono mode of operation In Dual Mono mode both amplifier channels get the same audio program at the same level To provide some direct control over the amplifier volume levels Channel Balance control is provided This control allows the adjustment of one amplifier channel out put volume over the other To reduce the volume level of channel B while leaving the volume of channel A unchanged the Channel Balance control is rotated counterclockwise The diminish ing arrow with the B next to it indicates that rotating the control in that direction diminishes the B chan nel volume Likewise for
17. e the rack attachments Table Mounting v x Feet are provided with the amplifier to allow it to i be placed on a tabletop Attach the included feet rP to the bottom of the amplifier as shown Attachment of the rack ears to the unit is option al and purely aesthetic for table mounting Installation Module Installation Installation Two input module bays are available to accept various Bogen input modules thereby allowing users to customize the amplifier to suit the needs of the installation Read the instructions included with the module and make the desired jumper setting changes before installing the module The sleep switch should be set to the desired position prior to installation of the right module since it will be covered by the module see Operation Sleep Mode Defeat The input modules are installed by simply sliding them along the card guides inside the module bays until the faceplate firmly sits against the M Class chassis then use the two screws supplied with the module to secure it to the chassis Card Guides Typical Module Note The input module included with the amplifier is pre installed and factory set for 0 dB gain can also be changed to 18 dB boost and to be muted by any other module can also be set to no mute To change those settings refer to the manual included with the module Connections Speakers Low Impedance Speaker Connections When the amplifier
18. gs convenience receptacles and the point where they exit from the apparatus Only use attachments accessories specified by the manufac turer Unplug this apparatus during lightning storms or when unused for long periods of time Refer all servicing to qualified service personnel Servicing is required when the apparatus has been damaged in any way such as power supply cord or plug is damaged liquid has been spilled or objects have fallen into the apparatus the apparatus has been exposed to rain or moisture does not operate normally or has been dropped Domestic and International Listings UL and C UL Listed IMPORTANT CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN CAUTION TO PREVENT THE RISK OF ELEC TRIC SHOCK DO NOT REMOVE COVER OR BACK NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED PERSONNEL The lightning flash with arrow head symbol within an equilat eral triangle is intended to alert the user to the presence of uninsulated dangerous voltage within the products enclosure that may be of sufficient magni tude to constitute a risk of elec tric shock to persons The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance servicing instruc tions in the literature accompa nying the appliance Contents Page INTRODUCTION 1 Pa
19. he Operation section In this mode P dii ow Field both channels are bridged into a single mono channel Use only speak ers that are designed to work with 70V audio systems when con necting to these terminals The speaker terminals can accept up to a 10 ring lug and have integral clamping plates which make wiring eas ier The 70V output terminals are indicated by a yellow field above them The polarity of the output terminals is indicated for speaker phasing purposes These output terminals must float and cannot be referenced to earth ground so if they become grounded the amplifier will go into protect mode shutting down operation of the amplifier even though no damage to the amplifier will occur Standard Input Module included Balanced Input Connections Balanced input connections are used when the source device pro Source vides a balanced output signal signal and ground G This equipment Mosis type of connection is desirable when operating in electrically noisy aS z ta environments where long input cable runs are needed or to ot ensure the lowest noise operation If compatible with the source DLO device this type of connection is recommended Unbalanced Input Connections When the source device provides only an unbalanced output Source Input Module signal and ground the input module should be wired with the Equipment s
20. iagram This mode also mixes the signals from each input module into a mono pro gram Input signals of modules that are assigned to the A m 70V bus are controlled by the A level control on the front of the unit and likewise for modules whose outputs are assigned to the B bus By assigning each module to a different bus a 2 1 mixer is formed with the front mount ed level controls adjusting the mix Additionally one module can be set to mute the other when it is active thereby providing an effective paging system see the section on Module Priority It is important in this mode to set the assignment jumpers on the two input modules so that their outputs are on different audio buses see the section on Audio Buses Speakers must be correct for 70V operation See section on 70V Transformer Coupled Speakers Right most position Level Control A Level Control A Power Mono Summing Mono Lo Cut Summing Filter Bridging Speaker Circuit Output Control Control B Control B AmpB Pre EQ Effects Post EQ Ou Loop Out Effects Post EQ 70V Mono Mode Block Diagram Dual Mono Mode Block Diagram Dual Mono Mode Placing the 3 position switch to its center position puts the amplifier in the Dual Mono mode of operation This mode is similar to the 70V Mono mode except that the amplifier supplies two channels of low impedance amplification in this mode see Dual Mono Mode Block Diagram This mode s
21. is set to either the stereo mode or the Dual LC Mono mode see Operation section low impedance speakers can 4 E connected to either the A or B speaker output terminals The amplifier is designed to work into speaker load impedances as low as CRD EAD 2 3 2 ohms The speaker terminals can accept up to 10 spade lug and have inte gral clamping plates which make wiring easier The polarity of each set of speaker outputs A amp B is indicated with a and sign Use these indicators to ensure that the phasing of the speakers are correct Do not ground the output of either set of outputs Doing so will cause the amplifier to go into protect mode shut ting down operation of the affected channel Note The and indicators are mirrored A and B outputs Be sure to make the correct connections Earth Ground Terminal The earth ground terminal is provided as a convenient means to con 1 1 1 nect to the amplifier s chassis AC ground if necessary DO NOT con fel nect the earth ground terminal to the terminals of either output D D No damage will occur if this is done but the amplifier will go into pro i i tect mode and shut down the effected channel 70V Transformer Coupled Speakers The 70V speaker output terminals are only usable when the amplifier is in the 70V Mono mode see t
22. l Knob Cover not shown see 4 on page 4 Removable cover protects both volume controls from casual tampering or brushing Y lt CLASS Z RING nnnnannnananaan n Y 0 0nm nnanananna JUUUUUUVUUUUU i PLAT a lt UUUUUUUUUUUUVU I nnnnnnnnnnn BF Fa gt B u nnnnh nnnnnnan 125 2 5 STEREO 8 5 70 UUVUUUVVUVVUUUUVV 15 5 MONO UUUUVUVVUVUUVUVUUUVU nnnnnnnnnnn nnn nn nnnnnnnnn B A EFFECTS LOOP OUTPUT FEED CHANNEL CHANNEL PREEQ POSTEQ VUUUUUUUU HE Accepts up to 10 spade lugs for low impedance speaker connections M Class Rear Panel 1 Low Impedance Outputs 2 Channel Balance Only active in Dual Mono mode Allows one channel s volume to be adjusted relative to the other channel 3 4 Effects Loop In Out The effects loop connectors provide an insertion point for outboard signal processing equipment when the M Class is operating in either 70V Mono or Dual Mono mode where inputs provide a 2 1 mixer function 5 6 Output Feeds Pre Post EQ Two different output feeds are provided that can supply signal to other audio equipment
23. oth channels driven at nominal line voltage 120V AC 60 Hz Requires 20A NEMA 5 20R Type Receptacle 15 BOGEN COMMUNICATIONS INC 50 Spring Street Ramsey NJ 07446 U S A Tel 201 934 8500 Fax 201 934 9832 Web Site www bogen com E mail info bogen com
24. pending on the application it may be more desirable to use the externally processed signal rather than the raw version of the signal Modes of Operation Stereo Mode Placing the 3 position switch to its left most position puts the amplifier in the stereo mode of operation The amplifier supplies two independent channels of low impedance amplification in this mode see Stereo Mode Block Diagram These channels can be used to supply left and right audio for stereo installations of 2 separate zones of amplification with different audio programs When using the supplied input module in this mode the input applied to the A input will be controlled by the A level con Left most position trol and the output will be available on the A channel speaker terminals Likewise for the B channel When using other modules there are jumper settings that allow those modules to apply signal to the A or B chan nels or both See the application examples for more information on how to use the two audio buses Level Control A Power AmpA Low Imp Speaker Output A Power Amp PreEQ Effects Low Imp Speaker Output B Out Loop Out Stereo Mode Block Diagram Mono Summing Level Control B 70V Mono Mode Placing the 3 position switch to its right most position puts the amplifier in the 70 Mono mode of operation The amplifier supplies a single channel of amplification in this mode see 70V Mono Mode Block D
25. rent installation needs Stereo Dual Mono or 70V Mono Front panel controls allow independent operation of each power amplifier channel in stereo mode In either 70V Mono or Dual Mono modes the inputs form a 2 1 mixer with the front panel controls setting the signal levels from each input Prioritized input modules and 2 1 mixer operation allow the M Class to supply the front end signal processing required in paging systems and the power to cover any size installation With three different models M600 M450 and M300 the M Class provides 2 channel operation at 600W 450W and 300W per channel into 4 ohm loads Single channel 70V Mono operation capacities are 1200W 900W and 600W Along with being powerful these amplifiers are also compact using up only 2 rack spaces 3 1 2 in a standard 19 rack Reliability Driven by a conservatively rated toroidal power transformer these amplifiers are built for solid performance with low distortion and a high slew rate Output module circuitry is located away from input module circuitry minimizing noise and ground loops The amplifiers require little maintenance and cleaning as internal electron ic components are located outside of the forced air stream flow Front mounted fan filters provide easy removal and cleaning M Class amplifers have a variety of electronic protection circuits including overcurrent DC voltage and ther mal circuits A special Clip Limiting circuit continuously monitors th
26. ront most cover screws on each side panel of the amplifier and attach rack ears as shown 2 Dust Filter Insert the dust filter into the fan grille before attaching the fan grille to the amplifier Filter Maintenance Dust filters are provided with the M Class amplifier to reduce the build up of dust on the heat sinks Periodic cleaning should be done when there is a noticeable build up of dust on the filters To clean the filters remove them from the grilles and wash vacuum or tap them out Promptly replace them Caution fan blades are accessible when the grille cover and filter are removed Be careful not to place your finger or other objects into the fan 3 Fan Grille To insert or replace the grilles first insert the tabs on the wider end of the grille in to the notches in the front center casting Snap the other end of the grille in to the snap slots Check that the grille is securely in place To remove pry the end of the cover closest to the rack ears up until the snap tabs disengage 4 Knob Cover To protect the amplifier controls from casual tampering the volume level controls are concealed behind a removable cover The cover snaps into place with tabs at the top and bottom To remove the cover squeeze both ends of the cover then gently dislodge the top and then the bottom Be careful not to tip the top of the cover too far forward while removing or the snap in tabs could be damaged To replace simply snap it back into pl
27. s affect the oper ation of the amplifier as much as the ones mounted on the amp Be sure to read the instructions with each module and be aware of its control setting when adjusting the overall operation of the amplifier 11 Application Examples Application 1 Simple 1 Zone 70 Mono telephone paging system with background music Background music plays through the system when no page is being made During a telephone page the background music mutes to a predetermined level and the telephone page is heard When the page is complete the background music fades back to its previous level Module Bus Assignment Priority Setting TEL1S Bus A only Priority 1 MAX1R Bus B only Priority 2 Mode of Operation 70V Mono Amplifier Adjustments Volume of the telephone page is adjusted by the A Level Control background music level is adjusted by the B Level Control Set the Lo Cut switch to 65 Hz Module Adjustments Adjust Gain to make each source s input level similar Adjust Bass amp Treble where applicable to your preference Adjust ducking control on MAX1R for desired level Adjust Gate controls of TEL1S for optimum paging control Application 2 Stereo low impedance music system with microphone override Stereo program material plays into low impedance speakers When the microphone becomes active the stereo music is muted to a predetermined level and the microphone is easily heard When the microphone signal stops the music fa
28. till mixes the input signal from the different modules but a Channel Balance control is provided to adjust the output DUAL MONO O levels of one channel against the other see the section on Channel Balance It is important in this mode to set the assignment jumpers on the two input modules so that their outputs are on different audio buses see the section on Audio Buses Speakers must be low impedance type not 70V type Center position Audio Buses The M Class amplifier contains two separate audio buses The A bus level is adjusted by the A level control on the front of the unit and the B bus is adjusted by the B Level control Most Bogen modules provide a means to assign their output to either or both of the audio buses The instructions that accompany the mod ules will describe the jumper settings for these assignments When using the M Class amplifier in either the 70V Mono or Dual Mono modes the module signals will be mixed For maximum control when mixing signals it is important that each of the two input modules be set so that the outputs feed different audio buses Otherwise proper mixing of the signals will be difficult Check that each module is set to a different audio bus before installing it 10 Modules Standard Input Module connectors labeled A amp B correspond to the similarly marked rear speaker 6 t lt connections and front panel controls S The module s inputs are permanently 6
29. ver the other zone Rotate the Channel Balance control towards the B marking counterclockwise to reduce the volume level of the speakers connected to the A output ter minals while leaving the volume level of B speaker output unchanged Module Adjustments Adjust Gain to make each source s input level similar Adjust Bass amp Treble where applicable as appropriate Adjust ducking control on MAX1R for desired level Adjust Gate controls of TEL1S for optimum paging control 13 Troubleshooting Status LED is off Status LED is green Signal LED is off Amplifier not plugged outlet dead Power switch off Breaker power switch tripped Turn off then turn back on Level controls turned down No signal from source Input module jumpers in wrong bus configuration if available Status LED is green Signal LED is green Clip Limit LED is off 70V mono connections on amplifier incorrect Poor broken speaker wiring Defective speakers Status LED is green Signal LED is green Clip Limit LED is off Input signal level too high Poor speaker connections Lo cut switch set to Flat 70V mono system only Status LED is green Signal LED is green Clip Limit LED is off Status LED is red green cycling Status LED is green Signal LED is green Lo cut switch setting Speaker wiring phasing Module bass control setting if available
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