576 Manual - Barry Rudolph
Contents
1. dbx PROFESSIONAL PRODUCTS 9 6 Vacuum Tube Preamplifier amp Compressor Owner s M anual Version 1 0 CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN 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 MOISTURE The symbols shown above are internationally accepted symbols that warn of potential 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 all servicing to qualified personnel Opening the chassis for any reason will void the manufacturer s warranty Do not get the unit wet If liquid is spilled on the unit shut it off immediately and take it to a dealer for service Disconnect the unit during storms to prevent damage U K MAINS PLUG WARNING A moulded 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 fuse2. 20 dB Pad to atten uate signals from hot sources such as high output microphones INVERT switch This switch inverts the phase of the incoming signal at the Mic input by swapping pins 2 and 3 on the XLR connector Phase inversion is typically used to overcome notchy sounding comb filtering effects when using multiple mics on a single source It can also be used when the audio cable from the source device has been wired to another pin arrangement 6 5760 Preamp Controls cont LOW CUT switch This switch places a 12 dB per octave shelving high pass filter in the signal path The knee frequen cy ofthe Low Cut filter is 75 Hz This filter is very useful for removing low frequency rumble or han dling noise from a microphone input signal It is also good for reducing the very low frequency com ponents of signals that can damage speakers or use up amplifier power unnecessarily LEVEL control This control determines the output level of the preamp section of the 576 It is used to moderate sig nal levels produced by the tube drive and EQ circuits There is 15 dB of gain control available LIMIT led This led illuminates when the output signal exceeds the level set by the Threshold control and it indi cates that PeakPlus limiting is occurring PeakPlus Limiter THRESHOLD control This control sets the threshold level at which the PeakPlus Limiter circuit becomes active The threshold range is from 0 dBu to 22 dB
3. 84070 Phone 801 568 7660 Fax 801 568 7662 Intl Fax 603 672 4246 Questions or comments E mail us at customer dbxpro com or visit our World Wide Web home page at www dbxpro com
4. Contact Your Local dbx Sales and Service Office or International Sales Office 68 Sheila Lane Valparaiso Indiana 46383 USA Tel 219 462 0938 Fax 219 462 4596 Table of Contents IntroductiON ccccccccsscsssssssecccsesesecsssscsssccssssssssssssssssssssssssssssssssssssssssssnssssscccsseceees 2 IKEL I i en PEE E EEE 2 TOS POCHOM A T ne ddascnndcUo Tan sosossani ncancocacecisiconesin 3 Warranty a AN 3 CNC AAA 4 Preamp COMtrOls ccccicicsccsecessccoscesccessouscesoasssesossscecssecdcensesceeescsecceescescassccsesesdccecseees 5 Compressor ConNtrOlS ysccscscdccsescnscvsdsnestsswaneccsnentevtesessessousnevedeysscsdenseedssosevessceniesesendesss 10 Rear Panel Preamp sess isscccisescavssnsesssoscececsadsevcsssosscasvedssvescasssisectasccavscesdesssscessetdasesee 14 Rear Panel Compressor vsccis iecscesecssisscessisecscsceschsscesenscovsosessscsacsauaceus ecsssscssaacasessscee 16 ES DECITICACION S Li A A AAA ia 17 Settings Page ncc ccccciscscsscescicesesdicsscsscccssesccsscesecuscsescscctecdcbeccsccoecsuscdescssdsnacnosccedsesdsescen 20 9 6 dbx Thank you for purchasing the dbx 576 vacuum tube preamplifier and compressor The 576 combines high quality microphone and instrument preamplification with world renowned dbx compression in a single chassis to offer you a flexible input path to your audio devices The dbx 576 s preamplifier circuit is a hybrid design consisting of a high voltage class A vacuum tube am
5. When activated this switch selects the rear panel line inputs as the source signal to the preamp When this switch is de activated the mic input is the source to the preamp DRIVE control This control sets the amount of gain that will be applied at the input of the vacuum tube stage The range of gain available is 10 to 60 dB The Drive control works in conjunction with the Level con trol to determine the degree of tube saturation to be applied to the signal For minimal tube saturation cleanest possible sound use relatively low settings of the Drive control and higher settings of the Level control Moderate amounts of tube character can be achieved with moderate settings of the Drive and Level controls if a high degree of tube saturation is desired this result can be obtained by using higher settings of the Drive control in conjunction with lower settings of the Level control Experiment with different settings of the Drive and Level controls to find the amount of tube satura tion that is right for you 48V switch This switch activates phantom power for condenser microphones on pins 2 and 3 of the XLR mic input You should connect your microphone before turning on the phantom power to prevent high voltage arcing that may damage your mic 20dB PAD switch This switch inserts a 20 dB attenuator circuit into the signal path from the microphone input The pad is inserted before the signal is routed through the mic preamp gain stage Use the
6. its sonic stamp to any signal routed through the Compressor When the Preamp and Compressor sections are connected in series a high Drive control setting can be used in conjunction with a high drive setting on the Preamp section to offer over the top distortion effects SC SIDECHAIN ENABLE switch This switch enables the Sidechain processing loop The Sidechain in and out connectors on the 576 rear panel allow external processing of the Compressor s detector signal This switch has no effect if there is nothing plugged into the Sidechain loop even though the switch will light when pressed For more discussion of the Sidechain see page 16 SC SIDECHAIN MON switch This switch allows you to monitor the sound of the Sidechain processing The switch will light when pressed to indicate that you are listening to the Sidechain not the main signal path CONTOUR switch This switch adds a gentle low frequency de emphasis into the detector path this is identical to hav ing an equalizer in the Sidechain loop only we ve done it for you This is extremely useful in keep ing low frequency program material from muffling or punching holes in the compressed signal This feature allows faster attack times and higher compression ratios with less artifacts The switch will light indicating contouring is activated 11 576 dbx BYPASS switch This switch bypasses the compression section completely The input is hardwired to
7. the output bypassing the tube amplification and VCA circuitry This feature is very useful for setting optimum compression and gain settings because it gives you an instant reference to the amount of effect you ve introduced to your signal LEVEL control This is the output gain control also known as a gain compensation or makeup gain control It is used to compensate for signal level lost due to compression and for excess gain contributed by the tube drive section There is 15 dB of gain control available with this knob PeakPlus LIMITER THRESHOLD control This control sets the threshold level at which the PeakPlus Limiter circuit becomes active The threshold range is from 0 dBu to 22 dBu off See page 7 for more information on the PeakPlus limiting circuit DRIVE LEVEL switch This configures the meter to show the signal level at the input to the vacuum tube Note that high gain settings can result in excessive movement of the meter as the needle contacts the endpin In this sit uation it s best to briefly check the drive level and then switch to one of the other meter modes GAIN REDUCTION switch This configures the meter to show the amount of gain reduction due to compression The lower mark ings on the meter show increasing gain reduction from right 0 dB to left 30dB Note that when configured to the Gain Reduction setting the meter swings from the fully right position and not the 0 dB position indi
8. which it is connected can result in full line voltage between chassis and earth ground Severe injury or death can then result if the chas sis and earth ground are touched simultaneously WARNING FOR YOUR PROTECTION PLEASE READ THE FOLLOWING WATER AND MOISTURE Appliance should not be used near water e g near a bathtub wash bowl kitchen sink laundry tub in a wet basement or near a swimming pool etc Care should be taken so that objects do not fall and liquids are not spilled into the enclosure through openings POWER SOURCES The appliance should be connected to a power supply only of the type described in the operating instructions or as marked on the appliance GROUNDING OR POLARIZATION Precautions should be taken so that the grounding or polarization means of an appliance is not defeated POWER CORD PROTECTION Power supply cords should be routed so that they are not like ly to be walked on or pinched by items placed upon or against them paying particular attention to cords at plugs convenience receptacles and the point where they exit from the appliance SERVICING To reduce the risk of fire or electric shock the user should not attempt to service the appliance beyond that described in the operating instructions All other servicing should be referred to qualified service personnel FOR UNITS EQUIPPED WITH EXTERNALLY ACCESSIBLE FUSE RECEPTACLE Replace fuse with same type and rating only MULTIPLE INPUT VOLTAGE T
9. 5 E ot E 2 y cot 2 cas RED E s Rotation Point Threshold 5 s54 We Above Threshold 5 y O 10 104 E OverEasy Range GREEN E 15 7 Below Threshold 157 Below Threshold c a e 15 10 5 O 5 10 15 20 15 10 5 O 5 10 15 20 INPUT LEVEL dB INPUT LEVEL dB Figure 3 Hard Knee and OverEasy Compression Curves RATIO control This control selects the ratio between input and the output levels for signals above the level set by the Threshold control It is adjustable between 1 1 no compression and infinity 1 full compression Note that when OverEasy processing is selected the ratio slopes gradually from the linear to the compressed region As the signal exceeds the threshold the ratio approaches the ratio set by the Ratio control ATTACK control This control sets the amount of time it takes the 576 to begin compressing a signal once the detector has sensed a signal above the threshold The attack range is from 3 dB msec for a tighter and more noticeable compression effect with very little overshoot to 04 dB msec for a more gradual compres sion that preserves attack transients A very fast attack setting will cause the 576 to act like a peak Limiter even though RMS average level detection circuitry is used Slower attack settings cause the 576 to act like an RMS or averaging detecting Compressor Limiter AUTO switch This switch overrides both the Attack and Release controls and enables preset program dependent attac
10. EAMP Microphone Input Connector Type Impedance Optimum Microphone Impedance Maximum Input Level CMRR Line Inputs Connectors Type Impedance Maximum Input Level Outputs Connectors Type Impedance Maximum Output Level Insert Send and Return Connectors Type Impedance Nominal Send Level Nominal Return Level EQUALIZER LOW Frequency 16 Female XLR Pin 2 hot Electronically balanced unbalanced 1 70 kQ 150 200Q gt 13 dBu or 33 dBu with 20 dB pad engaged gt 115 dB at 60 Hz gt 110 dB at 1 kHz gt 75 dB at 10 kHz Female XLR Pin 2 hot and TRS 1 4 Electronically balanced unbalanced gt 40kQ balanced gt 20kQ unbalanced or 470kQ unbalanced with rear panel INST switch engaged gt 30 dBu or 22 dBu with rear panel INST switch engaged Male XLR Pin 2 hot and TRS 1 4 Servo balanced unbalanced RF filtered Balanced 120Q unbalanced 60Q gt 21 dBu balanced or unbalanced TRS 1 4 Impedance balanced unbalanced Send Electronically balanced unbalanced Return Send 100Q balanced 50Q unbalanced Return 40kQ balanced 20kQ unbalanced 4 dBu 4 dBu 80 Hz shelving filter 5760 Specifications cont HIGH Frequency MID Frequency Gain all bands COMPRESSOR Threshold Range Ratio Threshold Characteristic Attack Release Characteristic Attack Release Modes Manual Attack Time Manual Release Time Auto Attack Time Aut
11. Limiter available on both channels e Mic Line and Hi Z instrument inputs to preamplifier e Class A Vacuum tube stage in compressor section with Drive control e Selectable dbx OverEasy compression curve e Pre EQ insert loop in preamp section Sidechain loop in Compressor section e Multi source VU metering and Peak indication e Ready for optional dbx TYPE IV Conversion System digital output module 9 6 Verify that the 576 s package contains the following e 576 Unit according to Model number marked on package e AC Power Cord e Operation Manual e Registration Card e Rack screws amp washers If any of these items are missing contact dbx customer service at 801 568 7660 This warranty is valid only for the original purchaser and only in the United States We warrant dbx products against defects in materials or workmanship for a period of two years from the date of orig inal purchase for use and agree to repair or at our option replace any defective item except exter nal power transformers without charge for either parts or labor IMPORTANT This warranty does not cover damage resulting from accident misuse or abuse lack of reasonable care the affixing of an attachment not provided with the product loss of parts or con necting the product to any but the specified receptacles This warranty is void unless service or repairs are performed by an authorized service center No responsibility is assumed for any speci
12. al inciden tal or consequential damages However the limitation of any right or remedy shall not be effective where such is prohibited or restricted by law Simply take or ship your dbx product prepaid to our service department Be sure to include your sales slip as proof of purchase date We will not repair transit damage under the no charge terms of this warranty dbx will pay return shipping NOTE No other warranty written or oral is authorized for dbx products This warranty gives you specific legal rights and you may also have other rights which vary from state to state Some states do not allow the exclusion of limitations of incidental or consequential damages or limitations on how long an implied warranty lasts so the above exclusion and limitations may not apply to you 3 9 6 dbx To connect the 576 to your system refer to the following steps e Turn off all equipment before making any connections e Mount the 576 in a rack with the rack screws provided The 576 can be mounted above or below anything that does not generate excessive heat Ambient temperatures should not exceed 95 F 35 C when equipment is in use Although the unit is shielded against radio frequency and elec tromagnetic interference extremely high fields of RF and EMI should be avoided where possible e Make audio connections via XLR 1 4 TRS or 1 4 TS plugs Refer to Fig 1 for a typical studio connection layout The XLR and 1 4 TRS co
13. cated on the top line of the meter OUTPUT LEVEL switch This configures the meter to show the output signal level This works in conjunction with the output level assignment switch on the back of the 576 When the rear switch is set to 4 dBu a meter read ing of 0 VU corresponds to 4 dBu output When the rear switch is set to 10 dBV a meter reading of 0 VU corresponds to 10 dBV output 9 6 sau LO LINE OUTPUTS WIRING SCHEME All of the input and output connectors are pin 2 hot meaning that pin number 2 on the XLR con necting cables carries the positive side of the balanced signal Pin number 3 is cold carrying the negative polarity and pin is the shield The 1 4 TRS jacks are wired so that when you use 3 con ductor cables and balanced signals the tip is hot the ring is cold and the sleeve is the shield The 1 4 jacks can also be used with 2 conductor unbalanced cables In this case the tip is hot and the ring and sleeve are grounded MIC INPUT Connect the cable from your microphone here If your mic requires phantom power ensure that the phantom power switch on the front panel is turned off before connecting your mic LINE INPUTS Both XLR and 1 4 TRS connectors are provided to allow balanced or unbalanced 4 dBu line level devices to be connected to the 576 These inputs can also be used for instrument level devices depending on the status of the Line Inst switch LINE INST switch To co
14. covers can be obtained from your local retailer Replacement fuses are 13 amps and MUST be ASTA approved to BS1362 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 Live As colours of the cores in the mains lead of this appliance may not corre spond with the coloured markings identifying the terminals in your plug proceed as follows e The core which is coloured green and yellow must be connected to the terminal in the plug marked with the letter E or with the earth symbol or coloured green or green and yellow e The core which is coloured blue must be connected to the terminal marked N or coloured black e The core which is coloured brown must be connected to the terminal marked L or coloured red CONDUCTOR WIRE COLOR LIVE BROWN BLACK NEUTRAL BLUE WHITE E EARTH GND GREEN YEL GREEN This equipment may require the use of a different line cord attachment plug or both depending on the available power source at installation If the attachment plug needs to be changed refer servicing to qualified service personnel who should refer to the table above The green yellow wire shall be connected directly to the unit s chassis WARNING If the ground is defeated certain fault conditions in the unit or in the system to
15. he Send and Return jacks into the signal path The insertion point is post tube pre EQ See page 15 for more details on the Insert feature LOW control This control varies the gain of the low frequency equalization the gain range is 15 to 15 dB The low frequency filter is a shelving lowpass configuration with a knee frequency of 80 Hz MID control This control varies the gain of the mid frequency equalization the gain range is 15 to 15 dB The mid frequency filter is a bandpass configuration with variable frequency and switchable bandwidth NARROW switch This switch selects the bandwidth for the mid frequency filter The default bandwidth is 1 5 octaves with the Narrow switch depressed the bandwidth is 0 5 octaves FREQUENCY control This control selects the center frequency for the mid frequency filter The frequency range is 100 Hz to 8 kHz HIGH control This control varies the gain of the high frequency equalization the gain range is 15 to 15 dB The high frequency filter is a shelving highpass configuration with a knee frequency of 12 kHz 576 dbx EQ switch This switch enables the equalizer When the equalizer is disabled the EQ circuit is hardwire bypassed This switch allows you to instantly assess the effect of your EQ settings PEAK led This red led illuminates when the 576 s internal signal level is within 3 dB of clipping The signal level is monitored at all critical stages of the circuit LINE switch
16. his equipment may require the use of a different line cord attachment plug or both depending on the available power source at installation Connect this equip ment only to the power source indicated on the equipment rear panel To reduce the risk of fire or electric shock refer servicing to qualified service personnel or equivalent ELECTROMAGNETIC COMPATIBILITY This unit conforms to the Product Specifications noted on the Declaration of Conformity Operation is subject to the following two conditions e this device may not cause harmful interference and e this device must accept any interference received including interference that may cause undesired operation Operation of this unit within significant electromagnetic fields should be avoided e use only shielded interconnecting cables DECLARATION OF CONFORMITY Manufacturer s Name Manufacturer s Address dbx Professional Products 8760 S Sandy Parkwa Sandy Utah 84070 USA declares that the product dbx 576 conforms to the following Product Specifications Safety EN 60065 1993 IEC65 1985 with Amendments 1 2 3 EMC EN 55013 1990 EN 55020 1991 Supplementary Information The product herewith complies with the requirements of the Low Voltage Directive 73 23 EEC and the EMC Directive 89 336 EEC as amended by Directive 93 68 EEC dbx Professional Products Vice President of Engineering 8760 S Sandy Parkway Sandy Utah 84070 USA July 1 1998 European
17. k and release times These times are derived from the characteristics of the input signal and con tinuously change to match its dynamics The switch lights indicating the attack and release times are being automatically adjusted in a program dependent fashion Enabling the Auto function duplicates the classic dbx sound of the 576 s forerunners which have become standards in the industry 10 576 RELEASE control The Release control sets how fast the compression circuit returns the input to its original level The release rate is from 250 dB sec where compression follows the envelope of the program material very tightly to 5 dB sec for very smooth compression UNLINK Switch This switch determines whether the input to the Compressor section comes from the Compressor s line input jack or from the output of the 576 s Preamp This is a convenience feature to allow you to use the Preamp and Compressor as two independent processors if desired When activated this switch unlinks the normal connection between the output of the Preamp and the input of the Compressor When de activated the Preamp and Compressor are placed in series for processing a sin gle signal source DRIVE control This control sets the amount of gain that will be applied at the input of the vacuum tube stage present in the Compressor section When the 576 s Compressor section is used independently of the Preamp section this control offers tube drive control with
18. l level returning to the 576 from an external unit switch in OUTPUT LEVEL switch This configures the meter to show the output signal level This works in conjunction with the output level assignment switch on the back of the 576 When the rear switch is set to 4 dBu a meter read ing of 0 VU corresponds to 4 dBu output When the rear switch is set to 10 dBV a meter reading of 0 VU corresponds to 10 dBV output DITHER switch This switch becomes active only when the optional dbx TYPE Iv Conversion System digital output module is installed Refer to the manual for the TYPE IV Conversion System for a description of the function of this switch SHAPE switch This switch becomes active only when the optional dbx TYPE Iv Conversion System output mod ule is installed Refer to the manual for the TYPE IV Conversion System module for a description of the function of this switch 15 125 AUTO 40 dB 20 I 00 1 3 pme E 250 dB Sec 5 THRESHOLD RATIO RELEASE PROFESSIONAL JRODUCTS ra COMPRESSOR 10 METER SOURCE 20 DRIVE GAIN OUTPUT O C ENABLE O MON O O LEVEL REDUCTION LEVEL 15 dB 15 15 dB 0 dBu Off Peak Plus DRIVE LENEL THRESHOLD Figure 2 Compressor Section of the front panel 0 THRESHOLD leds The led illuminates when the signal is above the OverEasy portion of the compression curve and that the full compression ratio is in effect If OverEasy is di
19. ng either balanced or unbalanced line level devices to the 576 The nominal output level can be set to either 4 dBu or 10 dBV with the 4 dBu 10 dBV switch 14 5760 Rear Panel Compressor COMPRESSOR SIDECHAIN RETURN O LINE OUTPUTS LINE INPUTS Both XLR and TRS 1 4 connectors allow balanced or unbalanced line level devices to be connect ed to the input of the 576 s Compressor section The nominal input level can be set to either 4 dBu or 10 dBV with the 4 dBu 10 dB V switch LINE OUTPUTS Both XLR and TRS 1 4 connectors are provided for connecting either balanced or unbalanced line level devices to the 576 The nominal output level can be set to either 4 dBu or 10 dBV with the 4 dBu 10 dBV switch SIDECHAIN SEND The Sidechain Send and Return allow external processing of the Compressor s detector signal The Sidechain Send is typically used to feed an external equalizer to produce compression that is triggered mostly by a specific frequency band The Sidechain Send jack taps the signal before the tube section without interrupting the main output from the Compressor This also allows the Sidechain Send to be used as an additional pre tube line level output The nominal output level is 4 dBu SIDECHAIN RETURN The output of an external device used for Sidechain processing of the detector circuit is connected here The nominal return level is 4 dBu 15 9 6 dbx Specifications PR
20. nnect instrument level devices to the 576 use either the 1 4 or XLR Line Input connector and depress the Line Inst switch Doing so will increase the input impedance and the gain applied to these inputs to make them suitable for devices using passive or piezoelectric pickups guitars etc The INST setting also reconfigures the Line Inputs as strictly unbalanced pin 2 tip hot pins 1 and 3 sleeve and ring grounded 13 576 dbx INSERT SEND and RETURN These connectors allow you to place another processor such as a de esser or Graphic EQ into the pre amp signal path This would generally be used to take advantage of the 576 s digital output option A signal from your microphone or instrument could be preamplified by the 576 processed externally through the INSERT I O and returned to the 576 to be passed along to the high resolution dbx TYPE Iv digital output The Send may also be used as a direct post preamp output that bypasses the EQ and main output stages of the 576 The Send is post preamp and the Return is pre EQ Both the Send and Return are balanced TRS jacks with 4 dBu nominal sensitivity The Return can also be used as an alternate input that makes use of the equalizer Limiter and digital output option without passing through the tube in the Preamp sec tion This input source would be selected by pressing the INSERT switch on the front panel LINE OUTPUTS Both XLR and TRS 1 4 connectors are provided for connecti
21. nnectors on the inputs and outputs can be used for bal anced or unbalanced connections However the use of more than one connector at a time on the input pair could unbalance balanced lines cause phase cancellations short a conductor to ground or cause damage to other equipment connected to the 576 e Verify that the fuse installed in the pull out fuse holder of the fuse receptacle matches the type and rating corresponding to the voltage in use as indicated on the rear panel of the 576 e Apply power Connect the AC power cord to the AC power receptacle on the back of the unit 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 power switch or from a master equipment power switch lo e o O To recorder input channel i To mixer for monitoring Figure 1 A typical 576 connection scheme 576 Preamp Controls Z PEAK NARROW H dB 15 15 dB m LOW MID FREQUENCY o 3 DECIBEL i x f y H PROFESSIONAL PRODUCTS LINE 0dB Ne PREAMP 10 15 15 30 METER SOURCE pawe INSERT OUTPUT LINE 48V CI PAD O O CUT ome dB 60 O O 15 dB 15 0 dBu Off DRIVE LEVEL Peak Plus THRESHOLD y O LEVEL Figure 1 Preamp Section of the front panel INSERT switch This switch enables the rear panel insert loop by inserting any device connected to t
22. o Release Time Output Gain LIMITER Type Threshold Range Ratio Stage 1 Attack and Release Time Stage 2 Attack Time Stage 2 Release Time SYSTEM PERFORMANCE DRIVE Control Range LEVEL Control Range 0 5 dB Bandwidth Frequency Response EIN 12 kHz shelving filter Sweepable from 100 Hz to 8 kHz bandwidth 1 5 octaves WIDE or 0 5 octaves Narrow Sweepable from 15 to 15 dB 40 dBu to 20 dBu 1 1 to inf to 1 Selectable OverEasy or hard knee curves AutoDynamic Selectable Manual or Auto Scalable program dependent Typically 3 dB msec to 04 dB msec Scalable program dependent Typically 250 dB sec to 5 dB sec Program dependent Typically 15ms for 10 dB Sms for 20 dB and 3ms for 30 dB Program dependent Typically 125 dB sec rate 15 to 15 dB PeakPlus Limiter 4 dBu to gt 22 dBu off Infinity 1 Zero Program dependent typically lt 5 msec Program dependent typically 22 dB sec 10 dB to 60 dB 15 dB to 15 dB 15 Hz to gt 90 kHz 0 0 5 dB lt 10 Hz to gt 200 kHz 0 3 0 dB Typically 126 dBu 150Q source impedance unweighted 22 kHz measurement bandwidth 17 9 6 dbx Specifications cont THD Noise Deviation From Linear Phase Interchannel Crosstalk POWER SUPPLY Operating Voltage Power Consumption Fuse Mains Connection PHYSICAL Dimensions Weight Shipping Weight 0 04 typical at 0 dBu out 1kHz 33 dB gain Drive c
23. ontrol at minimum Level control at maximum 3 5 typical at 21 dBu out 1kHz 35 dB gain tube saturation with Drive and Level controls at 50 lt 20 degrees 20 Hz to 20 kHz Typically 98 dB 20 Hz to 20 kHz Switchable between 100 120 230 and 240VAC 50 60 Hz 30 Watts max 100 120V 500mA 250V Slow Blow 5mm X 20mm 230 240V T250 mA 250V 5mm X 20mm IEC 320 Receptacle 3 5 H X 19 W X 8 D 12 lbs 5 5 kg 13 lbs 5 9 kg Note 0 dBu 0 775V RMS Specifications subject to change without notice g dbx 576 Settings Page Photocopy this page and mark the settings you use for your sessions INSERT Eo 15 dB 15 15 dB 15 LOW MID O PAD LINE 0dB LINE aye 48V 10 dB 60 DRIVE Session Comments es CJ O O ENABLE O MON 15 dB 15 DRIVE Session Comments Ory CONTOUR 100 Hz 8k 15 dB s C E HIGH LIMIT 0 5 INVERT LOW CUT 0 dBu Off Peak Plus THRESHOLD 15 dB 15 LEVEL 15 125 AUTO 3 dB mSec 04 dB Sec 5 ATTACK RELEASE LIMIT O 10 5 BYPASS 15 dB 15 LEVEL 0 dBu Off Peak Plus THRESHOLD PROFESSIONAL RODUCTS PREAMP METER SOURCE DRIVE INSERT OUTPUT LEVEL LEVEL LEVEL ODO Date PROFESSIONAL PRODUCTS COMPRESSOR METER SOURCE GAIN OUTPUT DRIVE LEVEL CO REDUCTION LEVEL OO Date 19 dbx PROFESSIONAL PRODUCTS 8760 South Sandy Pkwy Sandy Utah
24. plification stage coupled with an ultra low noise low distortion solid state driver stage The vac uum tube amplification stage is a classic high plate voltage design utilizing a pure class A topology A parallel triode arrangement is employed in addition to a fully regulated plate supply to maximize noise performance and transient response The premium grade 12AU7 vacuum tubes used in the dbx 576 are hand tested and graded specifically for gain noise and microphonics The compression section incorporates the features that have made dbx the standard for high quality audio compression Over Easy compression curve PeakPlus limiting and the advanced dbx V1 VCA module that ensures high system performance Precision 1 resistors are used through out the audio path to ensure performance stability and low noise To ensure years of trouble free oper ation each dbx 576 must pass a rigorous set of performance tests and a 24 hour burn in period before it is shipped from the factory We recommend that you take a moment to read through this operation manual It provides valuable information that will assist you in setting up and operating your dbx 576 e Flexible configuration useful as a single comprehensive input section or dual discrete channels e Low noise pure Class A vacuum tube preamplifier stage with adjustable Drive and Level controls e Flexible semi parametric EQ stage with low cut midband Q select and hardwire bypass e PeakPlus
25. sabled this led indicates that the signal is above the level set by the Compressor Threshold control and that compression is occuring The 0 led illuminates when the signal is in the OverEasy portion of the compression curve In this region the ratio varies as a function of signal level between 1 1 and the ratio set by the Ratio control This led will not light when the OverEasy function is off The led illuminates when the signal is below the level set by the Compressor Threshold control This indicates that the Compressor is not compressing and is operating in its linear region THRESHOLD control This control sets the level above which compression occurs and has a 60 dB range OverEasy switch OverEasy is a feature that provides a softer compression sound than hard knee does OverEasy smooths the transition from un compressed to compressed This smooth transition greatly reduces compression artifacts and allows faster attack times and higher compression ratios while still main taining the natural characteristics of the signal The switch lights to indicate OverEasy processing is enabled When conventional hard knee processing is desired disable the OverEasy function See Figure 3 for a comparison of OverEasy and hard knee compression curves 576 dbx Compressor Controls cont 20T RED Ae Above Threshold 20 H5T pen H a a 15 4 107 gt 104 a 2 m 57 e I m
26. u off The PeakPlus Limiter stage is a unique program Limiter featuring Intelligent Predictive Limiting Its function is to monitor the input signal and intelligently predict the amount of gain reduction needed to keep the output signal below the ceiling set by the PeakPlus control Note that since the PeakPlus Limiter is a fail safe Limiter it must come after the Output Gain con trol If the Output Gain is set too high as compared to the PeakPlus Level control continuous lim iting can occur While PeakPlus is typically used as a protective function creative effects can be achieved by intentionally driving the signal into heavy PeakPlus limiting Great care has gone into the design of the PeakPlus Limiter to keep it acoustically transparent Appropriate use of it can protect your gear while keeping the signal free of artifacts Peak Plus also serves to prevent digital overload when used in conjunction with the dbx Type IV Conversion System option DRIVE LEVEL switch This configures the meter to show the signal level at the input to the vacuum tube Note that high gain settings can result in excessive movement of the meter as the needle contacts the endpin In this sit uation it s best to briefly check the drive level and then switch to one of the other meter modes 576 dbx INSERT LEVEL switch This allows you to monitor the signal level sent post tube to an external processor unit switch out or the signa
Download Pdf Manuals
Related Search