Summary of Contents for 535

Page 1: ...amPoweredRadio Com I I I I I I I I I Murn model 535 DUAL GRAPHIC EQUALIZER model 533 GRAPHIC EQUALIZER UNITED RECORDING ELECTRONICS INDUSTRIES 8460 SAN FERNANDO RD SUN VALLEY CALIFORNIA 91352 818 767 1000 M re ...

Page 2: ... COMPLETE UNPACKING AND SETUP CONSULT UNPACKING AND INSPECTION INSTRUCTIONS ON PAGE 4 model 535 DUAL GRAPHIC EQUALIZER model 533 GRAPHIC EQUALIZER United Recording Electronics Industries 8460 SAN FERNANDO ROAD SUN VALLEY CALIFORNIA 91352 818 787 1000 Printed in U S A Copyright 1979 UREI ...

Page 3: ... 3 1 GENERAL 3 2 SYSTEM CHECK 3 3 EXPERIMENTATIO 3 4 DOCUMENTATION 3 5 APPLICATION 3 5 1 OBJECTIVE MEASUREMENTS VS SUBJECTIVE HEARING 3 5 2 ADDITIONAL HINTS 3 5 3 SPECTRAL DISTRIBUTION IN THE AUDIO SIGNAL 3 5 4 EQ SYSTEMS AND LIMITERS 3 6 DISCUSSION OF EQUALIZATION 3 6 1 BEFORE EQUALIZATION 3 6 2 MEASUREMENT TECHNIQUES 3 6 3 ADJUSTMENT OF EQUALIZERS 3 6 4 SOME PROBLEMS WITH CORRECTIVE ROOM EQ 3 6 ...

Page 4: ...RLOAD INDICATOH 4 7 POWER SUPPLY SECTION V MAINTENANCE 5 1 GENERAL 5 2 REPAIRS AND WARRANTY 5 3 SERVICE ADJUSTMENTS 5 3 1 COMMON MODE BALANCE 5 3 2 OFFSET ADJUSTMENT 5 4 CLEANING 5 5 ON OP AMPS SECTION VI ILLUSTRATION SCHEMATIC DIAGRAM OF UREI MODEL SCHEMATIC DIAGRAM OF UREI MODEL Continued PAGE 25 26 26 26 27 27 27 27 28 28 29 533 535 ...

Page 5: ...ominal level from as low as 20 dB Ref 0 775 V allowing its use with low level mixers high or low impedances and balanced or single ended circuits The Model 535 provides 12 dB of boost or cut at each of its 10 frequencies which are centered at ISO octave increments from 31 5 Hz to 16 kHz The positions of the control arms of the vertical stepless controls provide a graphic representation of the resp...

Page 6: ...TPUT LOAD 150 ohms or greater POWER OUTPUT 24 dBm into 600 ohm load 12 28 volts 20 dB into 150 ohm load 7 75 volts DISTORTION Less than 0 25 THD 30 Hz to 15 kHz at maximum rated output FILTER TYPE 2 pole synthesized L C FILTER BANDWIDTH 1 octave at 3 dB points with 8 dB boost or cut CENTER FREQUENCIES Standard ISO Hz 31 5 63 125 250 500 lk 2k 4k Bk 16k FREQUENCY ACCURACY RANGE OF BOOST AND CUT CAL...

Page 7: ...Panel is 3 18 mm 1 8 brushed clear anodized aluminum in two shades Chassis is cadmium plated steel WEIGHT Model 535 4 31 kg 9 5 pounds Model 533 2 95 kg 6 5 pounds SHIPPING WEIGHT Model 535 6 35 kg 14 pounds Model 533 4 08 kg 9 pounds ACCESSORIES Model SC 1 Security Cover smoke gray transparent plastic covers all operating controls Model 535 only 1 3 CONTROLS Model 301 XLR QG adapter two needed fo...

Page 8: ...ews and finish washers for rack mounting of 535 only 2 2 ENVIRONMENTAL CONSIDERATIONS The system will operate satisfactorily over a range of ambient temperatures from 0 C to 50 C 32 F to 122 F and up to 80 relative humidity If the system is installed in an equipment rack together with high heat producing equipment such as power amplifiers adequate ventilation should be provided to prolong the life...

Page 9: ...4 LINE VOLTAGE SWITCH Unless a tag on the line cord specifies otherwise the Model 535 was shipped ready for operation with nominal 115 VAC power mains In order to change this for nominal 230 V 50 or 60 Hz slide the VOLTAGE SELECTOR switch on the rear panel to the 230 position The voltage is visible in a window next to the switch slot Be sure to change the fuse to the correct value 1 8 amp slo blo ...

Page 10: ...ANCED INPUT AND BALANCED OUTPUT CIRCUITS OUTPUT GRD INPUT COM COM FIGURE 3 CONNECTING THE MODEL 535 WITH UNBALANCED INPUT AND UNBALANCED OUTPUT CIRCUITS With a balanced input and unbalanced output or vice versa use the appropriate connections suggested by each of the above diagrams No special switching or transformers are needed 6 ...

Page 11: ...www SteamPoweredRadio Com I I I I I I I I I I I I I I I I I I I 2 5 l MODEL 301 XLR QG ADAPTER i n rr Q _ cc w 0 c Oo CW c C G 0 0 0 cc E 6A 0 II u u 0 5 II ...

Page 12: ... change in frequency response Modern audio systems therefore utilize amplifiers and other active devices which have very low output impedances and high 10k to 50k input impedances These products may thus be cascaded operated in series or many inputs may be connected to a single output of a preceding device without regard to impedance matching Switching patching etc is simplified because double loa...

Page 13: ... clipping as a result of boost equalization 3 Output amplifier which is capable of delivering 24 d n into a 600 ohm load 12 3 V rms or 26 dBm into a 150 ohm load 7 75 V rms NOTE 26 dBm into 150 ohms is equivalent to 20 dB referenced to 0 775 volts i e 7 75 V rms 2 8 ACCESSORIES A security cover SC 1 may be installed over the front panel of the Model 535 only This protects all controls from unwante...

Page 14: ...ls and then tighten all hardware SEE SECTION 2 5 BEFORE INSTALLING THE ASSEMBLY IN A RACK 2 10 RACK MOUNTING TWO UNITS MODEL 533 The DR 21 kit optional allows mounting of two 533 s side by side in a standard 19 USASI rack The assembly occupies two standard spaces 3 1 2 high The DR 21 kit should contain the following items QUANTITY 2 2 2 4 4 DESCRIPTION Joining Plates Rack Mounting Angles Spacer Pl...

Page 15: ...ls with the rack mounting angles For precise alignment loosen the front panel mounting screws as well as the top and bottom cover screws 1 2 turn is adequate Adjust the relative positions of the angles and panels and then tighten all hardware SEE SECTION 2 5 BEFORE INSTALLING THE ASSEMBLY IN A RACK 18 32 Pan Head Screw 18 Lock Washer 16 32 Nut 16 Lock Washer 6 32 Oval Head Screw screws Rack Extens...

Page 16: ...nd effect of the individual filters and their almost unlimited number of combinations it is helpful to play with the controls and listen to the change in some familiar program material The EQ switch is very useful to make an instant A B comparison while altering adjustments 3 4 DOCUMENTATION The very nature of a graphic equalizer will result in many different control settings For later duplication...

Page 17: ...he intelligi bility of what otherwise would be a very boomy sound 3 Elimination of excess high frequencies and sibilance especially at high sound pressure levels A slight reduction in level at 8 kHz may eliminate much of the harshness which is experienced when loudspeakers and amplifiers are operated close to their power limits 4 Sound effect processing such as Telephone Sound 5 Room equalization ...

Page 18: ...nce destroy or reclaim the audio signal The extreme result would be a sound that never existed before In such instances there are very few rules for what to do and what not to do with the equalizer controls in creative equalization whatever works is right It is good to begin the work in a controlled environment where there is enough time to experiment and the freedom to do it wrong without offendi...

Page 19: ...ound muffled if too abundant The upper midrange is necessary for clarity and articulation but gives the program a canned quality if overused The high frequencies in excess create a harsh sound but if balanced give the audio program a spaciousness which it would not otherwise have 3 5 4 EQ SYSTEMS AND LIMITERS The use of a compressor or limiter in the audio chain is frequently dictated by the syste...

Page 20: ...est overall flatness of response through the entire audio range and in other instances some different response shape is desirable Three important characteristics of audio systems may be improved by judicious application of corrective equalization techniques They are 1 2 DISTORTION OF FREQUENCY RESPONSE BALANCE _ Sources of sound which may be amplified through a sound system start out with some spe...

Page 21: ...ant fields and inadequate projection of the higher frequencies which are necessary for the recognition of words The frequency band from approximately _ l kHz to 5 kHz is very important to the recognition of sibilant and consonant sounds and if the sound system has inadequate output in this frequency band or if other bands have considerably greater output which cover up the sounds in the intelligi ...

Page 22: ... tests which should be made prior to the start of correc tive room equalization The list is not intended to be exhaustive rather to point out that unless you know what the sound system IS doing you may find it difficult if not impossible to make it do what it SHOULD do A PARTIAL CHECK LIST OF PROCEDURES BEFORE EQUALIZATION 1 2 3 4 At normal operating levels check the frequency response and the sig...

Page 23: ...LED display Swept sine waves measured on an audio voltmeter or plotted on a graphic recorder Swept sine waves frequency modulated with a constant percentage bandwidth Warble Tone generated and plotted with the URE 200 2000 Recorder system Pulsed signals generated and measured with the URE SONIPULSE system Other methods as for example Time Delay Spectrometry are in the development stage and may bec...

Page 24: ... sample RAW HOUSE CURVE in Figure 6 we can infer that if an inverse electrical response curve were placed in the audio chain that the result would be a flat frequency response 5 5 15 15 o 50 13 10 100 12 eo 200 no 315 oo 100 130 100 1K UIK 1 K 2K UK JJIK K 1K UK IK 10t 1UK 11K FIGURE 6 TYPICAL RAW HOUSE CURVE OBTAINED FROM SONI PULSE MEASUREMENTS The octave graphic graphic equalizer is the tool wi...

Page 25: ...tural for high frequencies t O be attenuated more There fore if equalization is adjusted to create a perfectly flat response particularly throughout a large room the resulting sound will be excessively bright A house curve which produces a natural response in sound systems is subjective and a matter of personal preference as well as a function of the primary use of the location However a flat resp...

Page 26: ...d before the maximum output level from the equalizer may have peak values of approximately 20 dB Obviously the equipment is not properly matched Two solutions shall be discussed 1 2 We reduce the level through the equalizer to 20 dB average signal level This value is safe to provide us with 20 dB of headroom in the power amplifier At the same time however we reduce our signal to noise ratio As was...

Page 27: ...boosted as much as 20 dB due to the combining effect of adjacent filters Under such circumstances the signal should be reduced with the Gain control to a safe level to avoid overload 3 9 OVERLOAD INDICATOR Overload conditions are monitored throughout the equalizer The LED flashes ON when peak signals approach the clipping lev l in any part of the circuit It will remain ON long enough to be seen ev...

Page 28: ...y adjusted with Rl and is typically better than 40 dB 4 3 GAIN AMPLIFIER IC lB is a variable gain amplifier providing 15 to 15 dB of gain Thus the stage has a gain range of 30 dB allowing system gain from 10 to 20 dB 4 4 GRAPHIC EQUALIZER 4 4 l GENERAL The Graphic Equalizer consists of 10 L C R band filters tuned to ISO center frequencies IC 2A B C D 3C D 4A B C D Switch Sl selects either the inpu...

Page 29: ...akes place also but this voltage division is of the negative feedback thus as the impedance at the negative input of the amplifier is decreased the voltage at the output of the amplifier is increased With the control at midpoint any voltage division occurs equally in the input signal and feedback signal and the filter amplifier is once again a unity gain follower In the Model 535 the wiper of the ...

Page 30: ...nt flows through the inductor The active inductor circuit uses a capacitor and an operational amplifier to simulate the action of an inductor If we remove capacitor Cy from the circuit in Figure 7 we see that current flows into the circuit through resistor Ra to the virtual ground of the operational amplifier output If we now return capacitor Cy to the circuit we see that with increase in frequenc...

Page 31: ...m the output amplifier through CR 3 exceed the threshold set by the ratio of R48 and R49 the overload detector amplifier changes its output state for approximately 0 1 seconds and the LED indicates the overload co dicion The pulse stretching network included in the positive feedback loop of the amplifier ensures that the LED remains ON long enough to be observed even though the overload may have b...

Page 32: ...ich must accompany all repairs For prompt service ship the unit prepaid directly to the factory with the RA Number visible on the shipping label Be sure it is well packed in a sturdy carton with shock absorbing material such as foam rubber styrofoam pellets or bubble pack completely filling the remaining space Particular attention should be paid to protecting the controls switches etc Tape a note ...

Page 33: ... which may be connected to the output of the Model 535 UREI cannot be responsible for consequential damages due to misadjustment of this control PREFERRED METHOD With no input signal applied set the EQ switch to the IN position Measure the DC offset voltage of IC SA brown wire at the EQ switch and adjust R7 until the output of IC lC measures the same value red wire at the EQ switch The range of th...

Page 34: ...porated into the Model 535 with littLe if any modification We also realize that occasionally an IC will fail For this reason the table below lists a number of different operational amplifiers which will function as direct pin for pin replacements for the op amps in the 535 For one reason or another they may not function as well as the op amps originally supplied with this unit but for emergency re...

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