dbx 160X, Service Manual

Page 1: ...MODEL 160X XT Single Channel Compressor Limiter Preliminary ...

Page 2: ...r it appears alerts you to important operating and maintenance instructions in the accompanying literature Read the manual Manufactured under one or more of the following U S patents 3 377 792 3 681 618 3 714 462 3 789 143 4 097 767 4 329 598 4 403 199 4 409 500 4 425 551 4 473 795 Other patents pending This dbx branded product has been manufactured by AKG Acoustics Inc AKG is a registered tradema...

Page 3: ... damage that may have occurred during shipping If obvious physical damage is noticed contact the carrier immediately to make a damage claim We suggest saving the shipping carton and packing materials for safely transporting the unit in the future Verify that the 160XT package contains the following 160XT Unit 160XT Accessory Kit Operation Manual Warranty Certificate Registration Card 2 Please comp...

Page 4: ...of the signal presented to the master unit to prevent phase cancellation of the two signals from causing unmusi cal compressor action Note a 160X unit can also be used with the same results as long as the 160XT is used as the master unit Input Ground Lift Switch for isolation between shield ground and signal ground Useful when troubleshooting hum AC line interfer ence Other features include OverEa...

Page 5: ...n trols age Applications The dbx 160XT is capable of handling a wide range of applications In the studio the 160XT can be used on everything from vocals to percussion In live sound reinforcement the 160XT can allow the engineer to get that fat studio sound out of the drum kit or provide protection limiting for the speakers In radio or television broadcast the 160XT will produce stable voice levels...

Page 6: ... In OverEasy mode the threshold of com pression is defined as the middle of the OverEasy threshold region that is half way into compression as shown in Figure See Figure 3 THRESHOLD Indicators These three LEDs indicate the relationship of the input signal level to the threshold of compression The green BE LOW LED is ON when the signal is below threshold and the red ABOVE LED is ON when the signal ...

Page 7: ...d gain changes due to the OUTPUT GAIN control are not displayed by the GAIN REDUCTION LEDs but are re flected in the OUTPUT level display Rear Panel r3E F INPUT BALANCED OUTPUT QflE UNBALANCED OETECTOR LIFT o iUBBATIO __ I tip trs RING DC CONTROL SLEEVE GND_VOLTAGES Figure 2 Rear Panel SIGNAL INPUT Jacks The Tip Ring Sieeve phone jack and XLR type connector are wired in parallel either Signal Inpu...

Page 8: ... ground In the LIFT position it is disconnected This is not a chas sis isolate switch The circuit ground is floating with the respect to the chassis METER CALIBRATION Control This screw driver adjustable trimmer may be used to precisely calibrate the front panel s upper LED display so a OdB INPUT or OUTPUT indication is equivalent to any signal from 15dBu 138mVrms to 10dBu 2 45Vrms STEREO STRAPPIN...

Page 9: ...D reference level In OverEasy mode there is no distinct point at which processing be gins and the THRESHOLD setting corresponds to a point on the in put output transfer curve midway between the onset of processing and that point at which the transfer curve corresponds to the setting of the RA TIO control Figure 3 Figure 3 also shows how the 160XT s THRESH OLD indicator LEDs correlate with the comp...

Page 10: ...that an infinite increase in input level would be required to raise the output level by IdB In other words the output level is constant when the input signal is above thresh old The 160XT s RATIO control covers the entire range from 1 1 to 1 and in addition goes to Infinity negative ratios At a setting of 1 1 the above threshold input signal must increase by IdB in level to decrease the signal at ...

Page 11: ...mount of compression On the 160XT this is accomplished by means of the STRAPPING jacks a cable between these jacks permits the RMS de tectors of both units to talk to one another but only when one of the units SLAVE buttons is depressed The SLAVE unit then sends its signal to the MASTER where the RMS power of the MASTER and SLAVE sig nals are combined to generate a control voltage This control vol...

Page 12: ...are like those previously covered with reference to single channels of program material However it will generally be found that large amounts of compression are more audible in a mixed stereo program than they might be on the separate tracks that were mixed to cre ate the program Raising a signal out of a mix Since reducing dynamic range increases the average signal level by a small amount a singl...

Page 13: ...he EQ for example a po tentially damaging boost in EQ won t be seen by the 160XT and the speakers may be damaged see Multi way speaker systems page 14 r For maximum sound pressure levels large sound reinforcement systems frequently use a separate compressor on each output of the electronic crossover s For a stereo sound reinforcement system stereo strapping cables should be run between the 160XTs ...

Page 14: ...However gentle tapping of a drumstick or brushing of the cymbal will not be held back Assuming the tom tom is a lower frequency instrument and can be better tolerated by the tape it has less need for compression The equalization in the de tector circuit means that the compressor is not triggered as readily by a loud tom tom beat as by an equally loud cymbal crash The converse of the above EQ techn...

Page 15: ...pressor is to be used with a multi way speaker system i e before the crossover after EQ the system operator is faced with the problem of keeping levels below the point of destruction of the most sensi tive part of the system If for example mid range drivers are frequently damaged the whole system must be operated at a lower sound pressure level or additional mid range drivers must be added By inse...

Page 16: ... release recover from compression before the loud passage has ended IN DETECTOR IN AUDIO OUT 160XT Figure 7 Anticipated Compression Connecting the i6oxt to your system Basic Connection Figure 8 Basic Connection The 160XT can be connected for basic operation as shown in Figure 8 For more specific installation information refer to Installation Considera tions page 18 15 ...

Page 17: ...tereo designate one of the two units to be a MASTER SLAVE button OUT and switch the other unit to SLAVE mode SLAVE button IN SLAVE LED ON The master 160XT will now respond to the combined inputs of the 160XTs The master s controls will adjust the amount and nature of the compression and the slave will track accurately When the SLAVE switches on both units are not depressed the 160XTs operate compl...

Page 18: ...e 10 Figure 10 Using the 160XT with a Sampler Specific System Connections The 160XT has balanced inputs and outputs and can be used with any line level device Some common examples include mixing consoles mu sical instruments patch bays and other signal processors Mixing Board If you wish to compress a particular track of a multi track recording or one channel of a live performance mix the 160XT ou...

Page 19: ...o compress a live mix or to protect loudspeakers connect the 160XT be v tween the source mixing board or distribution amp and the power amp s If multi way loudspeakers with low level electronic crossovers are used the 160XT s should go after the crossover s For a stereo system you can separately stereo couple the two high band crossovers low band crossovers etc see page 16 If limitations require t...

Page 20: ...ally wired to the XLR type pin 3 the RING is wired to pin 2 and the SLEEVE shield is wired to pin 1 Note that pins 2 and 3 are the reverse of certain other manufacturer s equipment but if the same connection is used at the output the signal will be correctly polarized in phase Reversing the input wires to the input terminals will result in the output sig nal polarity being the opposite of the inpu...

Page 21: ...ROM SOURCE DEVICE MONO PHONE PLUG TO MONO PHONE PLUG PHONO PLUG TO MONO PHONE PLUG FROM SOURCE DEVICE XLR TYPE MALE FROM SOURCE DEVICE XLR TYPE MALE MONO PHONE PLUG TO MALE XLR TYPE PHONO PLUG TO MALE XLR TYPE Figure 12 Input Connections Unbalanced Operation NOTE for using Va Mono Phone Connectors 20 Connect the Sleeve to the cable s shield In an emergency V4 Mono Phone cables will work for inputs...

Page 22: ...O NEXT DEVICE a t n 1n T r L z_y U s 1 3D a n frrO 0 h C hd MONO PHONE PLUG TO MONO PHONE PLUG STEREO PHONE PLUG TO MONO PHONE PLUG FROM 160XT TO NEXT DEVICE FROM 160XT TO NEXT DEVICE CEZQti n hd an n R 10 n ji h T LJ 1 1 P S _b n 11 U U MONO PHONE PLUG TO STEREO PHONE PLUG STEREO PHONE PLUG TO STEREO PHONE PLUG FROM 160XT TO NEXT DEVICE FROM 160XT TO NEXT DEVICE a T B m cn flrf 0 0 i m MONO PHONE...

Page 23: ...output cable to the ground terminal of the 160XT leaving it unconnected at the receiving device The Ground Lift switch can be used to lift the shield at the 160XT s input Connecting Power A Check the line voltage The 160XT is shipped for 115V or 230V 50 or 60Hz opera tion Refer to the unit s rear panel to verify your unit s precise line voltage B Connect the 160XT s power cord to an appropriate AC...

Page 24: ... factory for service include a letter describing the problem Please refer to the terms of your Limited Two Year Standard Warranty which extends to the first end user After expiration of the warranty a rea sonable charge will be made for parts labor and packing if you choose to use the factory service facility In all cases you are responsible for trans portation charges to the factory dbx will pay ...

Page 25: ...and XLR type Connector Distortion THD 0 2 Any amount of compression 1kHz 0 2 SMPTE Equivalent Input Noise 89dBu Dynamic Range 113dB Gain Adjustment Level Matching Variable from 20dB to 20dB Threshold Threshold Characteristics Compression Ratio Attack Time Release Time Stereo Coupling Operating Voltage Operating Temperature Dimensions HxWxD Rack Space Weight Compressor 4OdBu to 20dBu Selectable Ove...

Page 26: ...ange 20 dB These features make the Model 160X compatible with the operating levels of virtually all professional sound and creative audio equipment For metering the 160X provides a true RMS dual wide range LED array which simultaneously shows the amount of gain reduction up to 40 dB and the input or output level from 40 dB to 20 dB depending on the setting of a front panel switch The 160X also fea...

Page 27: ...is below threshold and the red ABOVE LED is ON when the signal is above threshold When the 160X is switched to Over Easy mode the amber LED is ON when the signal is in the Over Easy region Refer to Figure 3 1 F COMPRESSION RATIO CONTROL Rotating this control in a clockwise direction increases the maximum amount of compression from 1 1 no compression up to infinity 1 no increase in RMS output regar...

Page 28: ... optional output configurations D METER CALIBRATION CONTROL This screw driver adjustable trimmer may be used to precisely calibrate the front panel s upper LED display so a 0 dB INPUT or OUTPUT level is equivalent to any signal level from 15 dBm 138 mV to 10 dBm 2 45 V E STRAPPING JACK When a suitable patch cord Tip Ring Sleeve phone plugs on a 2 conductor shielded cable joins this connector to th...

Page 29: ...ignation 2 Monitor the following points and verify the indicated conditions a TP10 24 30 Volts DC b TP11 24 30 Volts DC c TP12 15 Volts Dc 5 d TP13 15 Volts DC 5 3 Set the unit to the following modes a Unit not set to BYPASS b Unit set to MASTER c Display mode set to INPUT 4 Set the front panel controls to the following positions a THRESHOLD control set to O dBm b COMPRESSION RATIO set to 1 1 c OU...

Page 30: ...ack labeled SIGNAL OUTPUT 5 Adjust R7 for best VCA symmetry minimum control voltage feedthrough E Meter Calibration 1 Disconnect the signal generator from the STRAPPING input and connect it to the SIGNAL INPUT with a 1 4 phone plug this plug must be MONO or STEREO with the RING grounded 2 Set the unit to MASTER 3 Set the signal generator level to 0 dBm 0 775 V rms at 1 kHz 4 Verify that the meter ...

Page 31: ...ff 7 Slowly increase the generator level to 0 dBm Verify that the green LED turns off and the red LED turns on at a level between 1 5 and 0 dBm 8 The yellow LED between the green and red LED s should be off during this test H Infinite Compression Calibration 1 Set the signal generator connected to the input phone jack to a frequency of 1 kHz and a level of 10 dBm 2 45 V rms 2 Verify that the OVER ...

Page 32: ...20 I Alternate Signal Path Connection Tests Performance Tests 1 For this test a signal generator with a balanced output bridged is necessary Connect the signal generator to the XLR input connector The positive output should be pin 3 and the negative output should be pin 2 2 Monitor the output at the XLR output connector This is a balanced output with the positive output beins pin 3 and the negativ...

Page 33: ...han 89 dBm 27 5 uV rms It may be necessary to install the top cover to meet this specification The filter should be at least 3rd order 14 Repeat steps 7 through 13 driving the 1 4 phone jack input differentially balanced with the positive signal to the TIP and the negative signal to the RING and monitoring the 1 4 phone jack output but connecting the load resistor and capacitor from TIP to GROUND ...

Page 34: ...9 00 SWITCH 2 P0LE IN 0UT SW2 SW3 SWITCH 4 POLE IN 0UT SW4 SWITCH 6 P0LE IN 0UT SW1 1 72 noi 3 12 POT 20KB FOR 160X XT R68 R79 R86 3 08 _ ras KUjt TRANSFORMER POWER KNOB ASSY FOR 160X XT BUTTON CAP FOR SWITCHES KNOB CAP RED 15MM KNOB CAP BLUE 15MM KNOB CAP GREEN 15MM FRONT PANEL FOR 160XT 0NLY RACKEAR FOT 160X XT USER S MANUAL 160XT SERVICE MANUAL 160X XT USER S MANUAL 160A Rack tfiifi L 0 R 0jS u...

Page 35: ......

Page 36: ...IX c 2 ...

Page 37: ......

Page 38: ......

Page 39: ......

Page 40: ... i l t Hv It 0 t if M im ix Cl I tU Ju jro I 0HLED 13V 13V 2 V I L_ C1 StmV dB T0 9BIN CM4 LR0 v r 4 ra K r2 t 1 PI 4 P2 8 g p rr Pa V I P2 3 2 3fV BD EL 4 C A Z L 1 CR1 4 y RED INPUT LN222RP R2 CRIU7 i r i RfcO OUTPUT LN222RP R2 I A J i i 9V3 INPUT display Rf2 Z AAA _4 5 u x 33PF CO NPO ty i SV SLAVE l 3 2 y r A r j oo not scale this drawing tol dimension angle f REMOVE auras it SHARP EDGES rpfii...

Page 41: ...13 2X125 ...