1231 - Mixer DBX - Free user manual and instructions

USER MANUAL 1231 DBX

PLEASE READ THE FOLLOWING: KEEP THESE INSTRUCTIONSHEED ALL WARNINGSFOLLOW ALL INSTRUCTIONSCLEAN ONLY WITH A DAMP CLOTH.DO NOT BLOCK ANY OF THE VENTILATION OPENINGS. INSTALL INACCORDANCE WITH THE MANUFACTURERS INSTRUCTIONS.DO NOT INSTALL NEAR ANY HEAT SOURCES SUCH AS RADIA-TORS, HEAT REGISTERS, STOVES; OR OTHER APPARATUS(INCLUDING AMPLIFIERS) THAT PRODUCE HEAT.ONLY USE ATTACHMENTS/ACCESSORIES SPECIFIED BY THEMANUFACTURER.UNPLUG THIS APPARATUS DURING LIGHTNING STORMS ORWHEN UNUSED FOR LONG PERIODS OF TIME.WATER AND MOISTURE: Appliance should not be used near water(e.g. near a bathtub, washbowl, kitchen sink, laundry tub, in a wetbasement, or near a swimming pool, etc). Care should be taken sothat objects do not fall and liquids are not spilled into the enclosurethrough openings.POWER SOURCES: The appliance should be connected to a powersupply only of the type described in the operating instructions or asmarked on the appliance. GROUNDING OR POLARIZATION: Precautions should be taken so that the grounding or polarization means of an appliance is notdefeated.POWER CORD PROTECTION: Power supply cords should be routedso that they are not likely to be walked on or pinched by itemsplaced upon or against them, paying particular attention to cords atplugs, convenience receptacles, and the point where they exit fromthe appliance.SERVICING: To reduce the risk of fire or electric shock, the usershould not attempt to service the appliance beyond that described inthe operating instructions. All other servicing should be referred toqualified service personnel.FOR UNITS EQUIPPED WITH EXTERNALLY ACCESSIBLE FUSERECEPTACLE: Replace fuse with same type and rating only.MULTIPLE-INPUT VOLTAGE: This equipment may require the use ofa different line cord, attachment plug, or both, depending on theavailable power source at installation. Connect this equipment onlyto the power source indicated on the equipment rear panel. Toreduce the risk of fire or electric shock, refer servicing to qualifiedservice personnel or equivalent. SAFETY INSTRUCTIONS NOTICE FOR CUSTOMERS IF YOUR UNIT IS EQUIPPED WITH A POWER CORD.

WARNING: THIS APPLIANCE MUST BE EARTHED.

The cores in the mains lead are coloured in accordance with the following code:GREEN and YELLOW - Earth BLUE - Neutral BROWN - LiveAs colours of the cores in the mains lead of this appliance may not correspondwith the coloured markings identifying the terminals in your plug, proceed as fol-lows:• The core which is coloured green and yellow must be connected to theterminal in the plug marked with the letter E, or with the earth symbol, orcoloured green, or green and yellow.• The core which is coloured blue must be connected to the terminalmarked N or coloured black.• The core which is coloured brown must be connected to the terminalmarked L or coloured red.This equipment may require the use of a different line cord, attachment plug, orboth, depending on the available power source at installation. If the attachmentplug needs to be changed, refer servicing to qualified service personnel whoshould refer to the table below. The green/yellow wire shall be connected direct-ly to the units chassis. WARNING: If the ground is defeated, certain fault conditions in the unit or in thesystem to which it is connected can result in full line voltage between chassisand earth ground. Severe injury or death can then result if the chassis and earthground are touched simultaneously. LIVE

BROWN BLUE GREEN/YELBLACKNormal AltWIRE COLORWHITEGREEN The symbols shown above are internationally accepted symbols that warn ofpotential hazards with electrical products. The lightning flash with arrow-point in an equilateral triangle means that there are dangerous voltages pre-sent within the unit. The exclamation point in an equilateral triangle indi-cates that it is necessary for the user to refer to the owner’s manual.These symbols warn that there are no user serviceable parts inside the unit.Do not open the unit. Do not attempt to service the unit yourself. Refer allservicing to qualified personnel. Opening the chassis for any reason willvoid the manufacturer’s warranty. Do not get the unit wet. If liquid is spilledon the unit, shut it off immediately and take it to a dealer for service.Disconnect the unit during storms to prevent damage. CAUTION ATTENTION: RISQUE DE CHOC ELECTRIQUE - NE PAS OUVRIR

WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC

SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURERISK OF ELECTRIC SHOCKDO NOT OPEN IMPORTANT SAFETY INSTRUCTIONSU.K. MAINS PLUG WARNING A molded mains plug that has been cut off from the cord is unsafe. Discard the mains plug at a suitable disposal facility. NEVER UNDER ANY CIRCUMSTANCES SHOULD YOU INSERT A DAMAGED OR CUT MAINS PLUG INTO A 13 AMP POWER SOCKET. Do not use the mains plug without the fuse cover in place. Replacement fuse covers can be obtained from your local retailer. Replacement fuses are 13 amps and MUST be ASTA approved to BS1362.

IMPORTANT SAFETY INSTRUCTIONS

ELECTROMAGNETIC COMPATIBILITY This unit conforms to the Product Specifications noted on the Declaration of Conformity. Operation is subject to the following two condi- tions:

• this device may not cause harmful interference, and

• this device must accept any inter- ference received, including inter- ference that may cause undesired operation. Operation of this unit within significant electromagnetic fields should be avoid- ed.

Congratulations on your purchase of a dbx graphic equalizer. All dbx graphic equalizers are high performancemulti-functional units designed to deliver all the flexibility and power that professional users demand. We recom-mend that you take a moment to read through this operation manual. It provides information that will assist youfrom system set-up to EQ applications. The 12 Series Equalizers include the following features:• Switchable Boost/Cut range between ±6dB and ±15dB• Balanced inputs and outputs• XLR, Barrier Strip, and 1/4" TRS connectors• -12dB/+12dB input gain range• 18dB/octave 40Hz Bessel Low-Cut filter• Chassis/signal ground lift capability• Internal power supply transformer• Power-off hard-wire relay bypass with 2-second power-up delay INSPECTION Verify that the equalizer’s package contains the following:• Equalizer unit matching serial number marked on package• AC power cord• Operation Manual• Registration Card• Four rack mount screws and washersIf any of these items are missing please contact dbx customer service at the number provided on the back cover ofthis manual. OPERATING CONTROLS Front Panels 1231 - dual channel 31 band graphic equalizer1215 - dual channel 15 band graphic equalizer

+15Input Gain Control: This control sets the signal level to the equalizer. It is capable of -12dB to +12dB of gain. Its effect is apparent by viewing the OUTPUT LEVEL BAR GRAPH. EQ Bypass: This switch removes the graphic equalizer section from the signal path. (See Block diagram on Page 8.) The BYPASS switch does not, however, affect the INPUT GAIN, or LOW CUT filters. EQ Bypass LED: This red LED lights when the EQ is in bypass mode. Note that bypass mode only effects the graphic equalizer section of the 12 Series EQs. The INPUT GAIN and and LOW CUT controls remain unaffected when the EQ is bypassed. Boost/Cut Range Selection Switch and LEDs: This switch selects which of the two boost/cut ranges the equalizer will use, either ±6dB or ±15dB. The red LED lights when the ±15dB range is selected, and the yellow LED lights when the ±6dB range is selected. Note that the BOOST/CUT switch is slightly recessed. This is to prevent acciden- tal activation of the switch, possibly causing damage to other sound system components. Output Level Bar Graph: These four LEDs indicate output level of the equalizer. The red LED is 3dB below clip- ping and is marked as +18dBu. It monitors the level at the output of the equalizer after all other processing. Clip LED: This LED lights whenever any internal signal level reaches 3dB below clipping which may occur when any of the following happen: 1) the input signal is “hotter” than +22dBu, 2) excessive gain is applied by the input gain control, or 3) excessive boost is applied using the frequency sliders. Frequency Band Slider Controls: Each one of these slider potentiometers will boost or cut at its noted frequency by ±6dB or ±15dB, depending upon the position of the BOOST/CUT RANGE switch. When all the sliders are in the center detented position the output of the equalizer is flat. The frequency band centers of the 1231 are marked at 1/3rd of an octave intervals on ISO standard spacings, while the frequency band centers of the 1215 are marked at 2/3rds of an octave intervals on ISO standard spacings. Low Cut Enable Switch: The LOW-CUT switch inserts or removes the 18dB/octave 40Hz Bessel low-cut filter from the signal path. When the LOW-CUT switch is pushed in, the LOW-CUT filter is IN the audio path.

CONNECTING THE EQ TO YOUR SYSTEM

The 12 Series Equalizers have balanced inputs and outputs that can be used with any balanced or unbalanced line- level device. For more specific information about cabling possibilities, please refer to the section entitled Installation Considerations, Page 5. To connect the equalizer to your sound system refer to the following steps:

• Turn off all equipment before making connections.

• Mount equalizer in a standard-width rack. Install the EQs in a rack with the rack screws provided. It can be mounted above or below anything that does not generate excessive heat. Ambient temperatures should not exceed 113° F (45°C) when equipment is in use. Although the unit’s chassis is shielded against radio frequency and electromagnetic interference, extremely high fields of RF and EMI should be avoided.

• Make audio connections via XLR, barrier strip, or 1/4" TRS jacks (according to application needs) All three types of connectors for the inputs and outputs can be used for balanced or unbalanced connections. The use of more than one connector at a time for the inputs could unbalance balanced lines, cause phase cancel- lation, short a conductor to ground, or cause damage to other equipment connected to the equalizer. More than one output may be used simultaneously as long as the combined parallel load is greater than 600Ω.

• Select the operating range with the BOOST/CUT RANGE SELECTION switch Note: Be sure to reduce audio levels at the power amplifiers when changing the setting of this switch as it may generate an audible transient.

• Apply power to the equalizer Connect the AC power cord to the AC power receptacle on the back of the equalizer. Route the AC power cord to a convenient power outlet away from audio lines. The unit may be turned on and off from the rear panel OPERATION MANUAL

12 SERIES GRAPHIC EQUALIZERSpower switch or a master equipment power switch. Since the 12 Series Equalizers consume a relatively small amount of power, the units may be left on continuously.

REAR PANEL DESCRIPTIONS

Rear Panels 1231 - dual channel 31 band graphic equalizer 1215 - dual channel 15 band graphic equalizer Power Switch: Switches the power on and off. Always make audio connections with the power switch in the OFF position. Power Cord Receptacle: Connects AC power to the equalizer. Output Connectors: Three types of output connectors are provided for output connections: male XLR type con- nectors, 1/4" tip-ring-sleeve phone jack connectors and a barrier strip. Input Connectors: Three types of input connectors are provided for input connections: female locking XLR type connectors, 1/4" tip-ring-sleeve phone jack connectors, and a barrier strip. The maximum input level that the equal- izer can accept is +22dBu (ref: 0.775Vrms). Chassis Ground Lift Strap: By removing the jumper connecting the two screws on the barrier strip, the chassis ground is separated from the circuit ground of the equalizer. This is sometimes necessary to prevent “ground loops” in a sound system. When lifting the ground strap, you must make a connection from the circuit ground ( ) terminal to some other ground point in your audio system in order for the equalizer to function properly.

OUTPUT INPUTINPUTOUTPUTPROFESSIONAL PRODUCTSA HARMAN INTERNATIONALCOMPANYSALT LAKE CITY, UTAHMADE IN USAMODEL 1215EQUALIZERMANUFACTURED UNDER ONE OR MORE OF THE FOLLOWINGU.S. PATENTS: 4,234,804 4,316,107 4,329,598 4,331,931 4,403,1994,409,500 4,425,551 4,434,380 4,454,433 4,471,324 4,473,793OTHER PATENTS PENDINGWARNING: TO REDUCE THE RISK OF FIRE OR ELECTRICSHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURERISK OF ELECTRIC SHOCKDO NOT OPENATTENTION: RISQUE DE CHOC ELECTRIQUE - NE PAS OUVRIRCAUTION: TO REDUCETHE RISK OF FIRE REPLACEONLY WITH SAME TYPE FUSE.ATTENTION: UTILISERUN FUSIBLE DE RECHANGE DEMEME TYPE.24 WATTSPOWER100V 50/60Hz120V 60HzINSTALLATION CONSIDERATIONS Hookups and Cabling: The 12 Series Equalizers are designed for nominal +4dBu levels. The equalizers can be used with either balanced or unbalanced sources, and the outputs can be used with either balanced or unbalanced loads, provided the proper cabling is used. A balanced line is defined as two-conductor shielded cable with the two center conductors carrying the same signal but of opposite polarity when referenced to ground. An unbalanced line is generally a single-conductor shielded cable with the center conductor carrying the signal and the shield at ground potential. Input Cable Configurations: The equalizer has an input impedance of 40kΩ balanced and 20kΩ unbalanced. This makes the 12 Series Equalizers’ audio inputs suitable for use with virtually any low source impedance (under 2kΩ). Output Cable Configurations: The equalizer’s output is capable of driving a 600Ω load to +18dBu. For maximum hum rejection with a balanced source, avoid common grounding at the equalizer’s inputs and outputs. Most bal- anced (3-conductor) cables have the shield connected at both ends. This can result in ground loops which cause hum. If hum persists try disconnecting the shield on one or more of the cables in the system, preferably at the input of a device, not at the output.

OPERATION AND APPLICATION NOTES

The dbx 12 Series Graphic Equalizers are useful audio signal processing tools in situations where precise frequency control is required across the audible frequency spectrum. When used with an audio spectrum analyzer the EQs can tune any acoustical environment -- from the studio to the concert hall -- to stop ringing, increase clarity, and flatten the overall frequency response of the environment. A real-time spectrum analyzer or other types of audio environment analyzers are very useful in determining the amount of equalization needed. Insert the graphic equalizer between the signal source (usually a mixer) and the power amplifiers (or the crossover if there is one). Adjust the level and equalization as required to yield the desired system response. The long throw faders of the EQs allow very precise settings of the equalization for accurate equalization curves. For optimum signal-to-noise response, the gain structure of the sound system must be properly set up. Each compo- nent of the sound system should be set at its nominal operating level, starting with the first element in the system, usually a mixing console. Each element should be run at its nominal operating level in order to take advantage of the maximum signal-to-noise properties of that element. Loudspeaker amplifiers, as the last element in the chain, should be set only as loud as necessary, in order to avoid inducing unnecessary noise into the system.

The dbx 12 Series EQs are all solid-state products with components chosen for high performance and excellent reli- ability. Each unit has been tested and burned-in at the factory. No adjustment of any type should be required throughout the life of the unit. If circumstances arise which necessitate repair, we recommend that your EQ be returned to the factory. This can only be done by receiving a RETURN AUTHORIZATION number from dbx customer service. If you require technical support contact Customer Service. Be prepared to accurately describe the problem. Know the serial number of your unit (printed on a sticker attached to the chassis of the unit). Contact information is printed on the back cover of this manual.