Msr 602 Manual Form – Fill Out and Use This PDF

1.1 MSR-604 Mic / Line Sig na l Sp litter

flexibility of gain and level control, internal bus routing, signal meter- ing and a headphone monitoring facility.

The MSR-604 II is a four channel, four way signal splitting package and the MSR-602 II is the system power supply capable of supplying power for 40 channels, that is, 10 separate MSR-604 II units.

The MSR-604 II has four channels, each of which may be isolated and used totally independently from the next or, by internal re-configuration, be interconnected to form distribution amplifier sections with a single input driving up to 64 outputs.

The low noise floor requirement necessitates a remote power supply system, the MSR-602 II, which provides the required DC voltages.

A MIC/LINE switch introduces a 20dB input pad, which in combination with the 5 step GAIN switch allows any input signal below + 33dBu to be perfectly matched to the MSR-604 II’s dynamic range. The setting up process is further assisted by the provision of a momentary LISTEN switch which routes the signal to a calibrated HEADROOM meter and a headphone monitor amplifier built into the MSR-602 II power supply unit. Each channel also has a CLIP LED to give constant warning against signal overdrive. As a further refinement a separate 10dB input pad may be activated from the front of house mixing console by switching the desks phantom supply. This remote attenuator allows the engineer to preserve the channel headroom directly from the consolein the event that an input is overdriven.

Each channel also provides a separate phantom powering selector switch providing an independent 48V across the ‘mic input’ connector.

Each channel has two low impedance electronically balanced outputs on the rear panel to feed the MAIN (Front of House) and the MONITOR mixing consoles. These outputs may be independently configured by internal header blocks to drive at mic (+3dBu clip) or at line (+23dBu clip) levels. A third setting allows these outputs to be driven at +13dBu clip which gives a gain/headroom structure compatible with earlier versions of the MSR-604. The two FEED XLR connectors on the front panel offer microphone level transformer isolated and balanced outputs.

1.2MSR-602 II Pow er Sup p ly

The MSR-602 II is the system power supply providing all the neces- sary DC voltages for the MSR-604 II. It utilises a custom designed low field toroidal transformer and separate mumetal screen to reduce the possibility of mains field coupling into the electronic circuitry of the MSR-604 II.

The HEADROOM LED meter and high quality headphone amplifier give the operator absolute confidence in signal integrity during setting up, and provide an indispensable aid to trouble shooting and fault detection. The signal wiring involved is contained with the power wiring in a multicore cable for simple interconnection between units.

In addition it also carries the main system ground switch which has important considerations within a large system for both safety and noise.

PLEASE READ SECTIO N 4.2 CAREFU LLY PRIO R TO O PERATIN G TH E CO M PLETE SYSTEM .

2.1 Wa rra nty

2.2 Wa rning

As part of our system of quality control, this product is carefully inspected before packing to ensure flawless appearance. After unpacking the units, please inspect for any physical damage and retain the shipping carton and all relevant packing materials, should the unit require repacking.

In the event that damage has occurred, immediately notify your dealer, so that a written claim to cover damages can be initiated.

The MSR-604 II and MSR-602 II units are warranted by BSS to the original purchaser, against defects in workmanship and materials used in manufacture, for a period of one year from date of shipment. Faults due to purchaser misuse, unauthorised modifications or accidents are not covered by this warranty.

No other warranty is expressed or implied.

If the unit is faulty, it should be sent, shipping prepaid, to an authorised dealer of the manufacturer stating the faults found.

The serial number must be quoted in all correspondence relating to this warranty.

Because this equipment is connected between the microphone and mixing console or patching system, it is important for safety and system noise that a proper earthing system is implemented within the cabling system.

CO N SEQ U EN TLY SECTIO N 4.2 O F TH IS M AN U AL M U ST BE READ PRIO R TO IN STALLATIO N AN D U SE.

3.1AC Pow er Connec tions a nd Control Setting s

Before connecting the MSR-602 II to the AC power source, check that the voltage selector switch located on the rear panel is cor- rectly set. If a change is necessary, ensure that the mains fuse is also changed for one of the correct rating. Before connecting the DC power leads, check that the system ground switch on the rear panel is also correctly set to ‘earthed’.

The power cord attached to this unit carries the following informa- tion label.

WARNING: THIS APPLIANCE MUST BE EARTHED

IM PO RTAN T: The wires in this mains lead are colour coded in accordance with the following code.

3.11Volta g e Setting

The mains voltage selector switch provides simple, external adjust- ment for operation on all international AC power standards.

At each switch position there is an acceptable tolerance over which the performance of the unit will not be affected and this is 90v-130v for the 120V position, and 180V-260V for the 240V position. If you subject the unit to voltages in excess of this, you are likely to cause damage. If the mains voltage is below those specified, there will be reduced performance before the unit finally fails to work.

3.12Sa fety Ea rthing

The green/yellow wire of mains cord must always be connected to the electrical installations Safety Earth or Ground. I t is essential for personal safety, as well as proper operation of the unit, and is internally connected to all exposed metal surfaces. Any rack framework that this unit might be mounted into is assumed to be connected to the same grounding circuit. the MSR-604 II has electronically balanced audio connections and does not need disconnection of any safety earth for the avoidance of hum loops.

3.13AC Pow er Fusing

The incoming mains power is fused within the MSR-602 II by the fuse holder mounted on the rear panel. If it needs to be replaced it must be properly rated as: 20mm F5A for 240V voltage setting or F6.3A for 120V voltage setting. It is most important for continued safety that this specification is strictly adhered to, and you will have found that spare fuses of this rating are supplied together with your unit and manual.

It is very unlikely that this fuse will fail during normal use, and must be treated with some caution as to the cause, if it should do so. One of the most likely reasons will be because the mains voltage switch on the rear panel is incorrectly set. Another reason can be the inadvert-

3.2DC Pow er Connec tions

ent connection of line to line rather than line to neutral phase voltages when using a three phase supply. In either case internal transient suppressors (VDRs) can become damaged and will consistently blow replacement fuses. You may be assured that they have protected your unit from damage, but they will need removal to allow further use of your unit, and should be replaced as soon as possible to ensure con- tinued protection. If you feel this has happened, please refer to the appropriate section at the rear of this manual for the removal and replacement procedure.

DC connection between the MSR-604 II units and the MSR-602 II power supply is by the integral multicore cable with 9 pin D connectors. Note that the MSR-602 II power supply must always be located above the MSR-604 II units. (NB - this is opposite to the way early MSR-604s were racked.) Having the power supply at the top gives superior hum performance, and also places the HEADROOM meter and headphone amplifier in the most convenient position where they will not be obscured by cable looms from the FEED outputs. (Fig 4)

The topmost MSR-604 II’s LOOP IN cable is plugged into the power supplies LOOP OUT connector. Each remaining MSR-604 II is connected to the unit above it in similar fashion. Finally the male to female multicore D cable packed with the MSR-602 II is used to loop the final MSR-604 II’s LOOP OUT connector back to the LOOP RETURN socket on the power supply.

This ‘ring’ circuit allows a more reliable system set up, since an indi- vidual MSR-604 II may be isolated and removed from the rack without disturbing the power to the rest of the system. Ensure that the JACK SCREWS on the connectors are secured and tightened.

3.3 Aud io Connec tions

IN PU T (REAR PAN EL):

M AIN O U T (REAR PAN EL):

M O N O U T (REAR PAN EL):

FEED 1 AN D FEED 2 (FRO N T PAN EL):

The audio connections to the MSR-604 II are via XLR style connectors on the front and rear panels and their wiring configuration is as shown in figure 5.

Attention must be given to maintaining a consistent earthing system for safe and noise free operation. Please refer to section 4.2 for a fuller explanation and design guides.

This is electronically balanced, non floating and is for direct connection to the microphone, DI box or other source of programme. The input is fully RFI suppressed and has excellent common mode rejection performance.

Care should be taken to ensure continuity of the pin 1 earth connection.

The 48v phantom powering appears across this input when the channel phantom switch is operated. (Refer to section 3.2)

This is electronically balanced, non floating and should be connected to the ‘front of house’ mixing console or main control area. The remote attenuator facility looks at this connector for detection of phantom power voltage. This output should not be connected to an unbalanced input.

For consistent remote attenuator switching and microphone screening, it is important that the pin 1 earth connection is maintained. (See section 4.5 for configuring the output drive level.)

This is electronically balanced, non floating, and should be connected to the stage monitor mixing console or ancillary console which is being operated within the same grounding system.

This output should not be connected to an unbalanced input.

It is probable that the pin 1 earth connection will need to be disconnected at this point to avoid earth loops. (See section 4.5 for configuring the output drive level.)

These two identical outputs are actively buffered, fully transformer balanced and floating with primary/secondary isolation of 2.5kV. They are for connection to any other facility requiring a signal and are totally isolated and independent.

There is no connection to the pin 1 earth and all cable screening should be derived from the receiving end.

It is also important to ensure there is no earth connection to the shell of the mating female connector as this would make connection to the MSR-602 II chassis ground and cause potential ground loops.

3.4 MSR-602 II Controls

SYSTEM GRO U N D :

PO W ER:

This switch, located on the rear panel, is the main grounding point for all the MSR-604 II units connected to the system.

The switch will connect the electronic/signal ground to chassis earth when in the ‘EARTHED’ position.

The switch will disconnect the electronic/signal ground from chassis earth when in the ‘LIFTED’ position.

For a more detailed explanation of the grounding arrangements and implications of this switch, please refer to section 4.2.

The LEDs are used to indicate that the power is turned on and present. The LEDs are wired after the main DC Fuses, so should a fuse blow the corresponding LED will go out. The DC fuses are on the rear panel and are clearly marked with value and function. Always replace blown fuses with the correct value.

3.5MSR-604 II Controls

PH AN TO M O N / O FF

The MSR-602 II power supply provides each MSR-604 II with 48v DC for phantom powering capacitor microphones. This is selected by operating the individual channel switch and it is connected across the ‘input’ connector in the standard phantom powering manner. Typical current availability is 10mA per channel for a 40 channel system.

Phantom power is indicated by a front panel LED .

REM O TEATTEN U ATO R

LISTEN

A 10dB input pad is activated when the channel detects a +48v phan- tom signal is present on the MAIN OUTPUT. This allows the front of house mixing engineer to remotely reduce the input signal if he de- tects that the channel is being overdriven. This is a not uncommon occurrence in live rock and roll, when musicians get into the spirit of a performance and sing louder than during sound checks.

A front panel LED indicates when REMOTE ATTENUATOR is active.

Because the attenuator slightly degrades the noise and common mode performance of the unit it is recommended that the system is set up and calibrated without the remote attenuator activated, and that it is reserved for emergency use as described above.

The remote attenuator function cannot be disabled, so the engineer should observe the same caution with the desk phantom switch as he would if a phantom powered microphone were directly connected to the desk input.

CAU TIO N ! U SE O F TH E D ESK PH AN TO M SW ITCH IS ALM O ST CERTAIN TO PRO D U CE AN AU D IBLE CLICK SO IT IS

RECO M M EN D ED TH AT TH E CH AN N EL BE CLO SED BRIEFLY D U RIN G SW ITCH IN G.

Pressing the LISTEN switch connects the channel signal to the HEADROOM meter and headphone amplifier on the MSR-602 II power supply. It is a momentary switch which needs to be held in during monitoring.

The listen bus is arranged in such a way that only one channel will register on the monitor section at any time. If two listen switches are pressed at the same time the one that is closest in the chain to the PSU will register. See the MSR-602 II controls section for further details.

CAU TIO N ! ALW AYS TU RN LEVEL D O W N BEFO RE LISTEN IN G TO U N KN O W N SIGN ALS. H IGH EFFICIEN CY H EAD PH O N ES AN D A

H O T SIGN AL CAN PRO D U CE D AN GERO U S SO U N D PRESSU RE LEVELS. O BSERVE TH E W ARN IN G SYM BO L N EXT TO TH E H EAD PH O N E SO CKET.

4.3Cha nnel Co d ing

Fig . 9 C ha nne l C o d ing

In general the stage monitor console will be connected to the stage mains power grounding system so the signal connecting cables to the ‘MON OUTPUT’ connector will require the earth connection to be disconnected. That is, the cable screening will be derived from the monitor console, but should not be connected to the electronic 0v earthing system of the MSR-604 II via pin 1 of the connector. This disconnection would be implemented either in the connector, or at the monitor console multiway connector wiring point.

Other systems of earthing can be implemented, such as using the stage earth as the main star point, in which case the system ground switch would be set to ‘grounded’, or to use the stage monitor console as the main star point.

In any system it is important to remember:

a)Choose one star point for all grounding.

b)Ensure all microphone screening is permanently held to this ground.

c)Ensure that the two main earthing systems, namely stage and front of house, do not accidently short together.

d)Avoid sending signal currents along cable screens.

If these simple guide lines are followed, then implementation of the MSR-600 system will be completed without any troublesome earthing faults, and full safety will be implicit within the design.

In a system with more that one MSR-604 II unit, identifying which channel of which MSR is the actual system channel will become necessary, and the small pre-numbered self-adhesive labels supplied with the MSR-604 II can be used for this purpose. Figure 9 shows the fitting of these labels to the MSR-604 II front panel.

4.4Dua l Pow er Sup p ly Op era tion

Fig . 10 Dua l Po w e r Sup p ly C o nne c tio n

4.5Outp ut Drive Level Setting

The power supply of the MSR-600 system performs a vital role within the sound system and although designed to exacting standards for ultimate reliability, some systems will require a back-up which would automatically take over on failure of the main supply.

This is implemented within the MSR-600 system such that any two MSR- 602 II units can be directly connected together. Both units are switched on at all times, and power sharing ensures that the system will continue to operate should either unit fail (see figure 10).

Each MAIN output and MON output can be individually set to drive at mic or line level. A third setting which may be described as ‘Hot mic level’ is also available in order to provide a headroom structure which is compatible with previous versions of the MSR-604.

All outputs are set to mic level when the MSR-604 II leaves the factory. Note that the FEED outputs are set for clip at +3dBm (mic level) only and cannot be changed.

The OUTPUT LEVEL SELECT header blocks are clearly marked on the main PCB and are described in Table 1

4.6Multip le Outp ut Distrib ution Am p lifier Config ura tion

JU M PER SETTIN G

For use as a distribution amplifier, or in any situation where more than four outputs per channel are required, the MSR-604 II system may be reconfigured by moving internal jumpers. Up to sixteen adjacent channel sections, a total of sixty four outputs may be driven from a single input stage.

The simplified block diagram, Figure 12 shows the segmented internal bus which runs between adjacent channels. This bus is continued via the multiway LOOP connector between MSR-604 II units, allowing blocks of D .A. channel to span several output sections. Figure 12 shows the bus and the bus linking headers in their default settings, i.e. each channel input section is connected to its own output section. The default jumper positions are identified on the PCB by a white block printed adjacent to the relevant jumper pins. By way of exam- ple, Figure 13A illustrates a typical distribution amplifier arrangement where Channel 1 input section is used to drive its own and Channel 2’s output sections and, likewise, Channel 3 input is driving the out- puts of both Channel 3 and Channel 4.

CO N TRO LS

4.7Stereo Sum m ing C o nfig ura tio n

When a group of channels is linked as a D .A., the controls associated with the chosen input section are used to set the required operating conditions. the controls on the other channels are disabled, except for the CLIP LEDs and the LISTEN switches which may be used to confirm that the signal is reaching all the linked output stages.

Figure 13B above shows an alternate bus configuration where a stereo pair of inputs is used to drive two output channels in parallel. Each output is a sum of the pair of inputs reduced by 6dB.

5.1Insta lling MSR-604 IIs in a Mk I System

Limited compatibility exists between early MSR-604 systems and MSR604 II units using adaptor leads to interconnect the power cables.

Please order adaptor leads as MSR-604 Mk I adaptor kit Z-MSRIIADK-

01.This pair of cables is required for any of the system combinations described below . Only one adaptor set is required per system no matter how many new units are to be to be installed.

The MSR-604 II may be used to extend an existing rack which uses earlier versions of MSR-600 components. Although the Mk II units will perform better than the originals, some of the enhanced performance and features will be lost. In general the dynamic range will be reduced by about 2dB and the LISTEN monitoring function will not be available. Also channel bus linking will be restricted to operating within individual MSR-604 II units.

SETTIN G SYSTEM JU M PERS

RACK IN STALLATIO N

Remove the top cover plates on MSR-604 IIs and locate the two jumpers JP14 and JP15 next to the aluminium regulator heatsink. These jumpers will be shipped set to the factory default position, indicated by a solid bar printed on the PCB. Move the jumper blocks away from the default to cover the left and centre pins. It will be noted that yellow LEDs LD9 and LD10 do not now illuminate when power is applied. Replace the cover plate before installing in the rack.

The new units should be mounted at the top of the rack, away from the MSR-602 power supply. If more than one MSR-604 II is being installed, the LOOP IN/LOOP OUT connectors are ‘daisy’ chained’

5.2Insta lling Pre Mk II MSR-604s Into a New System

RACK IN STALLATIO N

5.3Insta lling a Mk II Pow er Sup p ly Into a Mk I System a nd Vic e Versa

together as described in section 3.2. Finally the pair of adaptor leads are used to insert the Mk II units into the systems power circuit.

Early MSR-604 units may be added to a Mk II system, but will gain no improvement in performance from the new system. They will run slightly warmer since they will be running from a higher DC voltage supply but there is no danger of damage or impaired reliability.

No changes are required to any internal jumpers or settings and provided that the Mk I units are installed at the ‘end’ of the DC daisychain, the performance of the Mk II units will not be affected in any way.

The Mk I MSR-604s should be mounted at the bottom of the rack, away from the power supply. Using the adaptor leads connect the Mk I units between the MSR-602 II LOOP RETURN socket and the final MSR-604 II LOOP OUT socket. If the units are wired into the DC loop wiring at a different point, the LISTEN BUS and the EXBUS-IN/- OUT linking between Mk II MSR units will be broken, disabling these functions.

Mixing Mk I and Mk II power supplies and systems is not generally recommended. Since they are designed to work at different DC rail voltages, performance and facility will be reduced to the lowest common denominator at best. Contact your BSS agent for availability and

6.1System Bloc k Dia g ra m a nd

Circ uit Desc rip tion

Fig . 14 M SR-604 II Blo c k Dia g ra m

advice if a replacement or a second power supply is required for a Mk I system.

Figure 14 shows the block diagram of the audio section of the MSR- 604 II. The DC supply regulator circuits (not shown) are common to all channels. The rails to each channel are protected by fusible resistors so that in the event of a short circuit fault in one channel the other three are not affected.

The input signal passes via RFI filters to the MIC/LINE switch, a bal- anced 20dB pad, and then to the REMOTE ATTENUATOR. This is a

6.2Tra nsient Sup p ressor

Rep la c em ent

Fig . 15 Tra nsie nt Sup p re sso r De ta ils

balanced 10dB pad using a relay controlled by a circuit which moni- tors the MAIN OUTPUT XLR for the presence of phantom DC voltage. The balanced signal then passes through the optional input trans- former, if fitted, and DC blocking capacitors to the low noise INPUT AMPLIFIER. This stage provides the common mode rejection trim, GAIN switch and provides a line level low impedance unbalanced drive signal to the BUS LINKING HEADERS. In the default mode the channel signal is not routed to the bus but is passed to the channel output stages.

The OUTPUT AMPLIFIER has two out of phase line driving outputs which are DC blocked and passed to both the balanced MAIN OUTPUT ATTENUATOR and the balanced MONITOR OUTPUT ATTENUATOR. The signals are then fed to the MAIN OUT and the MON OUT XLRs respectively. The low impedance attenuators ensure that a faulty cable or load on one output will not affect the other and also allow the output drive levels to be independently set to +23dBu, +13dBm, or +3dBm at clip. If the optional output transformers are installed, they are fitted in place of the attenuators and the output headroom is preset at +3dBu.

The FEED AMPLIFIER buffers the signal and drives the dual secondary isolating FEED TRANSFORMER which is connected to the two FEED output XLRs mounted on the front panel.

The LISTEN AMPLIFIER buffers the signal before presenting it to the LISTEN switch. This in turn is connected to the listen bus for monitor- ing on the HEADROOM METER and HEADPHONE AMPLIFIER which are located in the MSR-602 II power supply.

The primary of the mains transformer within the MSR-602 II is pro- tected against high voltage spike interference by two voltage depend- ent resistors. These provide a short circuit to voltage peaks in excess of their maximum rating.

Should the MSR-602 II be inadvertently connected to 3 phase line/line voltages, or to 240V when selected to 120V, or any other incorrect voltage, these suppressors are likely to fail in a protective short circuit mode. This will be demonstrated by repeated mains fuse failure when powering up the unit.

Even in this case of extreme overvoltage, the MSR-602 II is protected against failure, and the simple removal of these suppressors will allow the unit to be used again. However, it is important that they are replaced as soon as possible to ensure continued protection.

7.1Inp ut Tra nsform er Ba la nc ing

Figure 15 indicates the location and specification for the suppressors.

In some situations it might be necessary to provide a transformer balanced input and provision has been made within the MSR-604 II for it’smounting.

Please order as ‘MSR-604 II input transformer kit Z-MSRTXIII-01’. This is per channel, with four required for one MSR-604 II unit. Full fitting instructions are provided with this kit.

7.2Outp ut Tra nsform er Ba la nc ing

Provision has been made within the MSR-604 II to fit 600 ohm trans- formers to the ‘main’ and ‘mon’ outputs to provide floating and isolated outputs.