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Crown Audio STUDIO AMPLIFIER User's Manual

1. 120 20 100 1K 10K 20K FREQUENCY Hz Fig 6 9 Typical Common Mode Rejection Page 34 Studio Reference I amp Professional Studio Amplifiers croun 40 dB 60 Studio Reference Studio Reference I 100 120 20 100 1K FREQUENCY Hz Fig 6 10 Typical Crosstalk 10K 20K Page 35 croun 1 AC Power Draw and Thermal Dissipation This section provides detailed information about the amount of power and current drawn from the AC mains by Studio Reference amplifiers and the amount of heat produced under various conditions The calculations presented here are intended to provide a very realistic and reliable depiction of the amplifiers The following assumptions were made The amplifier s available channels are loaded and full standard 1 kHz power is being delivered Studio Reference I amp If Professional Studio Amplifiers Here are the equations used to calculate the data pre sented in Figures 7 1 and 7 2 Total output power with all x Duty channels driven watts AC Mains Power Cycle 4 Quiescent Power Draw watts Draw 90 watts Amplifier Efficiency 65 The estimated quiescent power draw of 90 watts is a maximum figure and assumes the fan is running at high speed The fol
2. PARALLEL BRIDGE MONO MONO CAUTION TURN OFF AMPLIFIER BEFORE CHANGING THIS SWITCH Fig 3 5 Stereo Wiring Page 11 croun making connections selecting sources and controlling output levels The load you save may be your own Crown is not responsible for damaged loads that result from carelessness or deliberate overpowering CAUTION Always disconnect the AC power and turn the level controls down when making or break ing connections This practice reduces the chance of loud blasts that can cause loudspeaker damage Studio Heference amplifiers provide three operating modes Stereo Bridge Mono and Parallel Mono Ste reo mode provides standard two channel operation Bridge Mono provides a single channel with double the output voltage of Stereo mode and Parallel Mono mode provides a single channel with double the output current of Stereo mode These modes can be selected using the stereo mono switch on the back panel Each mode is wired differently so be sure to note any spe cial wiring requirements for the mode you will be using 3 3 1 Stereo Two Channel Operation Stereo mode installation is very intuitive input chan nel 1 feeds output channel 1 and input channel 2 feeds output channel 2 To put the amplifier into Stereo Studio Reference I 8 IM Professional Studio Amplifiers mode turn it off slide the stereo mono switch to the center position and pr
3. e 21 43 2 Standby 2 21 4 3 3 Transformer Thermal Protection 21 4 3 4 Circuit Breaker 2 22 AA COMPOS V nn An ef et Ce e etie eng 22 4 5 Filter 0 0 222 0 23 5 Technical Information 24 551 OVEN EW a aa PALARO ata ba AMAG paaa 24 5 2 IA cadens sci ett AA maa 24 5 2 1 Stereo Operation 24 5 2 2 Bridge Mono Operation 26 5 2 3 Parallel Mono Operation 26 6 Specifications eerie idet 27 AC Power Draw amp Thermal Dissipation 36 8 cies ceva ia cde eee Aa 38 8I PEP AA 38 95 SEVICE AN nana 40 9 1 Worldwide ServiGe is e umia aa 40 9 2 North American Service 40 9 2 1 Service at a North American Service Center 40 9 2 2 Factory Service 222 22 2 40 4 Studio Reference I amp EI Professional Studio Amplifiers ILLUSTRATIONS Studio Reference Amplifier ErontEaGIlitiGS nem t bee trc ar rre remet aBar Facilities eS het et Mounting 2 2 Removing an End Cap Top View of a Rack Mou
4. m vz tanya Sania MOT 1 IH dNd NONE 19 39VIT0A 22159 pama tago Maans KANO uio 4 aasia Tw Y 7 SLNdNI avaa Maans gc sva a gt aaao le bel kasii kind Lo rm d 2 INTO 39VIS NIYO 9 15 LNdNI Bovis Houu3 18 lt __ _ ___ __ MOT IH NAN 1 Y 4 HOLV TISNVHL 44 4380 PE Fig 5 1 Circuit Block Diagram Page 25 croun output signal and the input signal from the gain pot and drives the voltage translator stage From the error amp the voltage translator stage chan nels the signal to the Last Voltage Amplifiers LVAs depending on the signal polarity The Q104 and Q105 and the LVA Q110 and Q111 drive the fully complementary output stage with their push pull effect through the bias servo Q318 The bias servo Q318 is thermally coupled to the heat sink and sets the quiescent bias current in the output stage to lower the distortion in the crossover region of the output signal With the voltage swing provided by the LVAs the sig nal then gains current amplification through the triple Darlington emitter follower output stage The bridge balanced circuit U104 D receives a sig nal from the output of the amplifier and differences it with the signal at the Vcc supply The bridge ba
5. Cf OW THE PROFESSIONAL AUDIO DIVISION OF CROWN INTERNATIONAL INC crown Referenc I crown Reference II Exported to select countries as Amcron Studio Reference PROFESSIONAL STUDIO AMPLIFIERS OWNER S MANUAL P O Box 1000 Elkhart Indiana 46515 1000 91995 by CROWN INTERNATIONAL INC 49 Telephone 219 294 8000 Printed on recycled paper Trademark Notice Studio Reference Smart Amp MPX 6 SMX 6 5 grounded bridge K80604 0 are trademarks and Crown IOC ODEP IQ System and P I P are registered trademarks of 8 95 Crown International Inc Other trademarks are the property of their respective owners THREE YEAR FULL WARRANTY WORLDWIDE NORTH AMERICA SUMMARY OF WARRANTY The Crown Audio Division of Crown International Inc 1718 West Mishawaka Road Elkhart Indiana 46517 4095 U S A warrants to you the ORIGINAL PURCHASER and ANY SUBSEQUENT OWNER of each NEW Crown product for a period of three 3 years from the date of purchase by the original purchaser the warranty period that the new Crown product is free of defects in materials and workmanship and we further warrant the new Crown product regardless of the reason for failure except as excluded in this Crown Warranty Note If your unit bears the name please substitute it for the name Crown in this warranty ITEMS EXCLUDED FROM THIS CROWN WARRANTY This Crown Warranty
6. Fig 2 1 Front Facilities 2 Facilities A Level Controls Each channel s output level can be adjusted accurately using the 31 position detented level controls on the front panel see Section 4 4 B ODEP Indicators During normal operation of the amplifier the ODEP Output Device Emulation Protection indicators glow brightly to show the presence of reserve thermody namic energy They dim proportionally as energy reserves decrease In the rare event that energy re serves are depleted the indicators turn off and ODEP proportionally limits the output drive so the amplifier can safely continue operating even under severe conditions These indicators also help to identify more unusual op erating conditions see Figure 4 2 00 Indicators The OC Input Output Comparator indicators serve as sensitive distortion indicators to provide proof of distortion free performance Under normal conditions the indicators remain off They flash if the output waveform differs from the input by 0 0596 or more see Section 4 2 If the input signal level is too high the indicators will also flash brightly with a half second hold delay to show input overload or output clipping Note The channel 2 IOC indicator stays on in Parallel Mono mode See Section 4 2 D Signal Presence Indicators These indicators flash synchronously with the amplifier s audio output to show signal presence Note These indi Page 8 cators may not flash at ver
7. 2 To ensure the safe transportation of your unit to the factory ship it in an original factory packing con tainer If you don t have one call or write Crown s Parts Department With the exception of polyure thane or wooden crates any other packing material will not be sufficient to withstand the stress of ship ping Do not use loose small size packing materi als 3 Do not ship the unit in any kind of cabinet wood or metal Ignoring this warning may result in extensive damage to the unit and the cabinet Accessories are not needed do not send the instruction manual cables and other hardware If you have any questions please call or write the Crown Technical Support Group Crown Audio Division Tech Support Factory Service 57620 C R 105 Elkhart Indiana 46517 U S A Phone 1 219 294 8200 U S 1 800 342 6939 Fax 1 219 294 8301 Page 40 Detach and send with unit Crown Factory Service Information Shipping Address Crown International Inc Factory Service 57620 C R 105 Elkhart Indiana 46517 Phone 1 800 342 6939 or 1 219 294 8200 Fax 1 219 294 8301 Owner s Name Shipping Address Phone Number Model Serial Number Purchase Date NATURE OF PROBLEM Be sure to describe the conditions that existed when the problem occurred and what attempts were made to correct it Other equipment in your system If warranty has expired payment will be W Cash Check W VISA
8. TURN OFF AMPLIFIER BEFORE CHANGING THIS SWITCH Fig 3 6 Bridge Mono Wiring Page 12 Studio Reference I amp IM Professional Studio Amplifiers greatly degraded Also turn down the channel 2 level control fully counterclockwise Note The channel 2 input and level control are not de feated in Bridge Mono mode Any signal feeding chan nel 2 will work against the channel 1 signal and usually results in distortion and inefficient operation Connect the load across the two red binding posts see Figure 3 6 The positive 4 loudspeaker lead connects to the red channel 1 binding post and the negative or ground lead from the loudspeaker con nects to the red channel 2 binding post Do not con nect the black binding posts Also the load must be balanced neither side shorted to ground CAUTION Only connect balanced equipment meters switches etc to the Bridge Mono output Both sides of the line must be isolated from the in put grounds or oscillations may occur 3 3 3 Parallel Mono Operation Parallel Mono mode is used to drive loads with a total impedance of less than 4 ohms see Bridge Mono if the load is 4 ohms or more Wiring for Parallel Mono mode PARALLEL MONO MODE THAM CHANNEL 1 MIXER THE CHANNEL 2 INPUTS ARE NOT USED crouln is very different from the other modes and requires special attention To select Parallel Mono mode turn off the amplifier and sli
9. its sides should be at least 2 inches 5 cm away from the cabinet see Fig ure 3 3 Also open rack spaces should be covered to prevent heated air from the side vents from being drawn out the front of the rack into the front air intake You will know when your Studio Reference amplifier has sufficient cooling because its ODEP indicators will be brightly lit If tne amplifiers ODEP indicators dim or turn off overly demanding conditions are forcing it to protect itself from overheating If you experience a cooling problem you should consider several factors that may be contributing to the problem including load impedance air flow and ambient air temperature Low impedance loads generate more heat than higher impedance loads To avoid impedance related cooling problems connect loads to each channel with a total impedance of at least 2 ohms in Stereo 4 ohms in Bridge Mono and 1 ohm in Parallel Mono mode see Section 3 3 for wiring instructions If your loads are reasonable and you still have a cooling problem check for shorts in the loudspeaker cables and look for prob lems with air flow or ambient air temperature Air flow restrictions are the most common cause of inad equate cooling Restrictions may result from improper IMPORTANT Be sure the back of the amplifier is supported 4 AMPLIFIER TOP VIEW t AIR FLOW Fig 3 3 Top View of a Rack Mounted Unit Studio Reference 8 IM Profess
10. 3 16 Loudspeaker Fuse Nomograph Page 18 Studio Reference I amp IM Professional Studio Amplifiers A better approach is to fuse each driver independently This allows you to apply the most appropriate protec tion for the type of driver being used In general low frequency drivers woofers are most susceptible to thermal damage and high frequency drivers tweeters are usually damaged by large transient voltages This means that your loudspeakers will tend to have better protection when the woofers are protected by slow blow fuses and high frequency drivers are protected by high speed instrument fuses Depending on the application you may want to use a specialized P P module to protect your loudspeak ers Again some modules are more appropriate for long term thermal protection while others are more ap propriate for protection against transients A Smart Amp IQ P I P module is most commonly used for long term loudspeaker thermal protection Each Smart Amp channel provides an independent smooth output limiter that controls average output levels over time while it allows transients to pass Most of the other P P modules that provide signal driven compression can be used to prevent loud speaker damage from transient voltage These modules include the P I P AMCb P I P EDCb and P P PA While the P I P EDCb is most commonly used for general loudspeaker protection the P I P AMCb is very popular in systems that
11. 3 dB from 3 Hz to 32 8 kHz Studio Reference 1 dB from 5 Hz to 28 6 kHz 3 aB from 2 3 Hz to 34 4 kHz Output Power The following are guaranteed minimums for low distortion 1 kHz power from units configured for 120 VAC 60 Hz power For more information on power specifications see the matrices that follow Studio Reference Stereo mode with both channels driven 1 160 watts into 4 ohms 780 watts into 8 ohms Bridge Mono mode 2 220 watts into 8 ohms 1 580 watts into 16 ohms Parallel Mono mode 2 315 watts into 2 ohm 1 565 watts into 4 ohms in in 42 3 D in in nn Studio Reference Stereo mode with both channels driven 555 watts into 4 ohms 355 watts into 8 ohms Bridge Mono mode 1 110 watts into 8 ohms 715 watts into 16 ohms Parallel Mono mode 1 115 watts into 2 ohm 710 watts into 4 ohms in in 42 in in Load Impedance Safe with all types of loads Rated for 4 to 8 ohms in Stereo mode 8 to 16 ohms in Bridge Mono mode and 2 to 4 ohms in Parallel Mono mode Required Mains 50 or 60 Hz 100 120 200 220 or 240 VAC 1096 Both units draw 90 watts or less at idle See Section 7 for detailed information on AC power draw current draw and thermal dissipation It is extremely important to have adequate AC power for the amplifier Power amplifiers cannot create energy they must have the required voltage an
12. 4 Continuous power in the context of Federal Trade Commission testing is understood to be a minimum of five minutes of operation Har monic distortion is measured as the RMS sum total and given as a percentage of the funda mental output voltage This applies for all watt ages greater than 0 25 watts Bridge Mono balanced output 240 VAC 50 Hz Parallel Mono co oo AIAI INIo ojo 2 Mm ojoj A Fig 6 1 Studio Reference Minimum Power Matrix Page 29 crouJn Page 30 100 VAC 50 Hz 120 VAC 60 Hz 240 VAC 50 Hz Studio Reference I 8 IM Professional Studio Amplifiers Studio Reference Minimum Guaranteed Power Watts Stereo Mono Mode Stereo both channels driven Maximum Average 0 196 THD N See note 1 0 1 THD N 0 05 THD N See note 2 20Hz 20kHz See note 3 1 kHz 1 kHz 20Hz 20kHz 70 FTC Continuous Average 0 1 THD Noise See note 4 4 340 Bridge Mono balanced output 960 680 Parallel Mono Stereo both channels driven Bridge Mono balanced output Parallel Mono Stereo both channels driven Bridge Mono balanced output Parallel Mono 4 4 Qs co HB AINI QD co A Fig 6 2 Studio Reference Minimum Power Matrix Studio Reference I amp Professional Studio Amplifiers crown Maximum Power
13. DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE are located nearby The field is strongest just above and below the unit If an equipment rack is used we recommend locating the amplifier s in the bottom of the rack and the preamplifier or other sensitive equipment at the top WATCH FOR THESE SYMBOLS The lightning bolt triangle is used to alert the user to the risk of electric shock The exclamation point triangle is used to alert the user to important operating or maintenance instructions crown Studio Reference I 8 If Professional Studio Amplifiers CONTENTS 1 Welcome ANA a 7 GA 7 PA ILI Se CL 8 3 1 2 2 ccr einer nitate iode 10 MOUNTING AS ace nasty ettet age eet edunt 10 3 2 COOlIMG AE WAA tote eet eeu 10 Qa LA a A 11 3 3 1 Stereo Two Channel Operation 12 3 3 2 Bridge Mono Operation 12 3 3 3 Parallel Mono Operation 13 3 34 Input Connection 22 14 3 3 5 Output Connection 16 3 3 6 Additional Load 18 3 4 AG Mains POWER fee D etes Ens 18 4 Operation errem idee rein 19 4 PRECAUTIONS cens GAAN BANG 19 432 INGICALOLS er RR e aha Ka UR ERU 19 4 3 Protection Systems 2222 2 22 7 22 00 20
14. bus inputs and outputs adjustable input sensi tivity phantom power and RFI suppression Input isola tion transformers are optional For more information on these P Ps or other PI P s un der development contact your local dealer or Crown s Technical Support Group Page 39 crouJn 9 Service This unit has very sophisticated circuitry which should only be serviced by a fully trained technician This is one reason why each unit bears the following label CAUTION To prevent electric shock do not remove covers No user serviceable parts inside Refer servic ing to a qualified technician 9 1 Worldwide Service Service may be obtained from an authorized service center Contact your local Crown Amcron representa tive or our office for a list of authorized service centers To obtain service simply present the bill of sale as proof of purchase along with the defective unit to an authorized service center They will handle the neces sary paperwork and repair Remember to transport your unit in the original factory pack We will pay the surface shipping costs both ways for warranty service to the authorized service center nearest you after receiving copies of all ship ping receipts You must bear the expense of all taxes duties and customs fees when transporting the unit 9 2 North American Service Service may be obtained in one of two ways from an authorized service center or from the factory You may choose either I
15. input sensitivity Remove the P I P module to access the sensitivity switch CH 2 O INPUT GROUND LIFT LIFT AFFECTS PHONE INPUTS ONLY BALANCED INPUT WIRING TIP RING GND SLEEVE INPUT AIRING aga NY SLEEVE GROUND LIFT SWITCH Fig 4 5 Input Sensitivity and Ground Lift Switches switch to the left to isolate or lift the grounds Note The noninverted and inverted signal lines for the P I P module are connected in parallel with the corre sponding lines of the phone jack inputs The input sig nal grounds are not paralleled Specifically XLR pins 2 and 3 are connected in parallel with the tip and ring of the corresponding phone jack However pin 1 of the XLR is not connected in parallel with the sleeve of the phone jack This makes it possible for a P I P module to handle its own signal grounds independently The amplifier s circuit breaker protects the power sup plies from overload The breaker s reset switch is lo cated on the back panel Facing the back panel move the reset switch the left to disconnect power to the power supplies or to the right to reconnect power If the circuit breaker trips the front panel enable indica tor will turn off If this occurs turn off the enable switch flip the reset switch to the right on and then turn the enable switch back on If it trips again or the amplifier does not operate properly contact an authorized ser vice cent
16. of the details of design production or variations of the equipment Nor does it cover every possible situation which may arise during installation operation or maintenance If your unit bears the name Amcron please substitute it for the name Crown in this manual If you need special assistance beyond the scope of this manual please contact our Technical Support Group Crown Audio Division Technical Support Group 57620 C R 105 Elkhart Indiana 46517 U S A Phone 800 342 6939 U S A or 219 294 8200 Fax 219 294 8301 IMPORTANT STUDIO REFERENCE AMPLIFIERS REQUIRE CLASS 1 WIRING CAUTION AVIS RISQUE DE CHOC ELECTRIQUE N OUVREZ PAS RISK OF ELECTRIC SHOCK DO NOT OPEN TO PREVENT ELECTRIC SHOCK DO A PREVENIR LE CHOC NOT REMOVE TOP OR BOTTOM ELECTRIGUE N ENLEVEZ COVERS NO USER SERVICEABLE PAS LES COUVERTURES PARTS INSIDE REFER SERVICING RIEN DES PARTIES TO GUALIFIED SERVICE PERSON UTILES A L INT RIEUR NEL DISCONNECT POWER CORD D BRANCHER LA BORNE BEFORE REMOVING REAR INPUT AVANT D OUVRIR LA MODULE TO ACCESS GAIN SWITCH MODULE EN ARRI RE Magnetic Field CAUTION Do notlocate sensitive high gain equip ment such as preamplifiers or tape decks directly above or below the unit Because this amplifier has a high power density it has a strong magnetic field which can induce hum into unshielded devices that WARNING TO REDUCE THE RISK OF ELECTRIC SHOCK
17. period THIS STATEMENT OF WARRANTY SUPERSEDES ANY OTHERS CONTAINED IN THIS MANUAL FOR CROWN PRODUCTS Telephone 219 294 8200 Facsimile 219 294 8301 9 90 SUMMARY OF WARRANTY The Crown Audio Division of Crown International Inc 1718 West Mishawaka Road Elkhart Indiana 46517 4095 U S A warrants to you the ORIGINAL PURCHASER and ANY SUBSEQUENT OWNER of each NEW Crown product for a period of three 3 years from the date of purchase by the original purchaser the warranty period that the new Crown productis free of defects in materials and workmanship and we further warrant the new Crown product regardless of the reason for failure except as excluded in this Crown Warranty ITEMS EXCLUDED FROM THIS CROWN WARRANTY This Crown Warranty is in effect only for failure of a new Crown product which occurred within the Warranty Period It does not cover any product which has been damaged because of any intentional misuse accident negligence or loss which is covered under any of your insurance contracts This Crown Warranty also does not extend to the new Crown product if the serial number has been defaced altered or removed WHAT THE WARRANTOR WILL DO We will remedy any defect regardless of the reason for failure except as excluded by repair replacement or refund We may not elect refund unless you agree or unless we are unable to provide replacement and repair is not practical or cannot be timely made If a refund is ele
18. require a high quality crossover and the P P PA is the proces sor of choice for applications that require a microphone and line level input for each channel And finally the Smart Amp IQ P I P DP provides both an input com pressor for transient protection and a smooth output limiter for long term thermal protection For more infor mation on P P modules see Section 8 3 4 AC Mains Power All Studio Reference amplifiers are shipped with an appropriate line cord and plug The 120 VAC 60 Hz North American Studio Reference has a special plug and includes a matching receptacle Al ways use an isolated power receptacle whenever pos sible with adequate voltage and current Excessive line voltages 1096 or higher above the rated voltage will cause the amplifier to activate its standby mode see Section 4 3 2 For example do not exceed a 132 VAC with models rated for 120 VAC operation Unless otherwise noted all specifications in this manual were measured using 120 VAC 60 Hz power mains with voltage accurate to within 0 596 and THD of less than 1 096 under all test conditions Performance variations can occur at other AC mains voltages and line frequencies Line regulation problems will directly affect the output power available from the amplifier Studio Reference I amp Professional Studio Amplifiers 4 Operation 4 1 Precautions Although your amplifier is protected from internal and external faults you sho
19. supply output battery or power main Such connections may re sult in electrical shock 10 Tampering with the circuitry by unqualified person nel or making unauthorized circuit changes may be hazardous and invalidates all agency listings Remember Crown is not liable for damage that results from overdriving other system components 4 2 Indicators The front panel has several helpful indicators The en able indicator is provided to show the amplifier has been turned on or enabled and that its low voltage GCrown Signal 10 ODEP eee 5 0 5 Fig 4 1 Indicators power supply and on demand forced air cooling sys tem are working It does not indicate the status of the high voltage power supplies For example the enable indicator will stay on in the improbable event that one or both channels overheat causing an internal shut down of the high voltage supplies The green ODEP indicators confirm the normal opera tion of Crown s patented Output Device Emulation Pro tection circuitry During normal operation they glow brightly to confirm the presence of reserve thermody namic energy They dim proportionally as the energy reserve decreases In the rare event that there is no reserve the indicators will turn off and ODEP will pro portionally limit the drive level of the output stages so the amplifier can continue safe operation even when the operating conditions are severe For a more de tailed d
20. the instruc tions in Section 3 3 4 Another problem to avoid is the presence of large subsonic currents when primarily inductive loads are used Examples of inductive loads are 70 volt step up transformers and electrostatic loudspeakers Inductive loads can appear as a short circuit at low fre quencies This can cause the amplifier to produce large low frequency currents and activate its protec tion circuitry Always take the precaution of installing a high pass filter in series with the amplifier s input when inductive loads are used A three pole 18 dB per oc tave filter with a 3 dB frequency of 50 Hz is recom mended some applications may benefit from an even higher 3 dB frequency Such a filter is described with the subsonic frequency problems in Section 3 3 4 Another way to protect inductive loads from large low frequency currents and prevent the amplifier from pre maturely activating its protective systems is to parallel a 590 to 708 uF nonpolarized motor start capacitor and 4 ohm 20 watt resistor in series with the amplifier out put and the positive transformer lead This circuit is shown in Figure 3 15 It uses components that are 4 ohm 20 watt Resistor 590 to 708 uf Capacitor 120 VAC N P From Amplifier Output Inductive Load Fig 3 15 Inductive Load Transformer Network Page 17 crouJn available from most electrical supply stores 3 3 6 Additional Load Protection
21. 17 dB below rated full bandwidth power Total Harmonic Distortion THD Less than 0 02 at rated low distortion 1 kHz power Less than 0 196 at rated full bandwidth power Intermodulation Distortion IMD 60 Hz and 7 kHz 4 1 Studio Reference Less than 0 005 from full band width power to 78 watts rising linearly to 0 025 at 78 milliwatts Studio Reference Less than 0 005 from full band width power to 36 watts rising linearly to 0 02526 at 36 milliwatts Damping Factor Greater than 20 000 from 10 Hz to 200 Hz and greater than 2 500 at 1 kHz see Figure 6 6 Crosstalk At rated full bandwidth power Studio Reference Better than 100 dB from 20 Hz to 100 Hz falling linearly to better than 70 dB at 20 kHz see Figure 6 10 Studio Reference Better than 100 dB from 20 Hz to 100 Hz falling linearly to better than 65 dB at 20 kHz see Figure 6 10 Common Mode Rejection CMR At rated full band width power See Figure 6 9 Voltage Gain With level controls set for maximum output At the 26 dB gain setting 20 1 3 or 26 dB 0 25 dB Studio Reference At 0 775 volt sensitivity 103 1 12 or 40 dB 1 dB at 1 4 volt sensitivity 57 1 12 or 35 dB 1 dB Studio Reference At 0 775 volt sensitivity 69 1 12 or 37 dB 1 dB at 1 4 volt sensitivity 38 1 12 or 32 dB 1 crouln Power Power Bandwidth At standard 1 kHz power Studio Reference 1 dB from 5 Hz to 27 5 kHz and
22. 4 ohms and Parallel Mono mode is used to drive a single channel with a load impedance of less than 4 ohms WARNING Turn off the amplifier before changing this switch see Section 3 3 0 Balanced Phone Jack Inputs A balanced i inch phone jack is provided for input to each channel They may be used with either balanced tip ring and sleeve or unbalanced tip and sleeve in put wiring see Section 3 3 These inputs are in parallel with the P P connector so they should not be used as inputs if the installed has active circuitry Caution Do not use the channel 2 input in either mono mode P Ground Lift Switch The input signal ground may be isolated from the AC ground with this switch to help prevent unwanted ground loops It affects only the phone jacks O It has no affect on the P J P module s XLR connectors Activat ing the switch inserts an impedance between the sleeve of each phone input jack and the circuit ground Input Sensitivity Switch The three position input sensitivity switch inside the am plifier can be accessed by removing the P P module Settings include 0 775 volts and 1 4 volts for rated out put and 26 voltage gain see Section 4 4 Page 9 crouJn 3 Installation 3 1 Mounting Studio Reference amplifiers are designed for standard 19 inch 48 3 cm rack mounting or stacking without a cabinet In a rack it is best to mount units directly on top of each other This provides the
23. Distortion Noise See note 2 Bridge Mono balanced output 120 VAC 6 0 Hz Parallel Mono Stereo both channels driven Bridge Mono balanced output 100 VAC 50 Hz Parallel Mono Stereo both channels driven Bridge Mono balanced output 240 VAC 50 Hz Parallel Mono PP NO oc A AINI AJ AINI QD Cc co A Fig 6 4 Studio Reference Maximum Power Matrix Studio Reference I 8 IM Professional Studio Amplifiers crown 2 1 0 1 1 watt 8 ohm 2 dB 4 3 4 5 6 7 10 100 1K 10K 100K FREQUENCY Hz Fig 6 5 Typical Frequency Response 100 000 10 000 DAMPING 1 000 100 10 20 100 1K 10K 20K FREQUENCY Hz Fig 6 6 Typical Damping Factor 1 0 1 OHMS 0 01 0 001 0 0001 20 100 1K 10K 20K FREQUENCY Hz Fig 6 7 Typical Output Impedance Page 33 crown Studio Reference 1 8 If Professional Studio Amplifiers 135 90 45 45 90 135 20 100 1K 10K 20K FREQUENCY Hz Fig 6 8 Typical Phase Response 0 20 40 dB 60 100
24. Specifications Crown s maximum power specifications represent the largest amount of output power you can expect from your ampli fier when it is driven to full output under the given conditions These specifications can be used to prevent loudspeaker and hearing damage The maximum power matrices include specifications for single cycle and 40 millisecond burst sine waves Burst signals act like large transient peaks that are present in common source signals Loudspeakers can respond to a single cycle burst so the single cycle burst specifications should be used to help you protect your loudspeakers In contrast a 40 millisecond burst represents the typical response time of the human ear Your ear will not respond to the entire dynamic change of a burst that lasts less than 40 milliseconds The burst power specifications are provided at 0 05 THD which is a practical low distortion condition Operating the amplifier at levels higher than 0 05 THD can result in output power levels that are higher than those listed in the maximum power matrices Maximum Power Notes All maximum power specifica Studio Reference Maximum Power Watts ud psc t 17 Single Cycle Tone Burst 40 Millisecond Tone Burst less than 1 096 and an ambi Stereo Mono 0 05 Distortion Noise 0 05 Distortion Noise entrar temperature of 70 F Mode See note 1 See note 2 21 C Although it is an un usual condition your ampl
25. Studio Heference amplifiers can deliver very high power levels so it s a good idea to add protection for your loudspeakers if it is not built in Loudspeakers are subject to thermal damage from sustained overpower ing and mechanical damage from large transient volt ages In both cases fuses may be used to protect your loudspeakers or you may opt for the convenience of a P I P module that provides similar protection Thermal protection and voltage protection require dif ferent types of fuses Slow blow fuses are used to pre vent thermal damage because they respond to thermal conditions like a loudspeaker High speed instrument fuses like the Littlefuse 361000 series are used to pro tect loudspeakers from transient voltages The nomo graph in Figure 3 16 can be used to select the correct fuse for thermal or voltage protection There are two common ways to install the fuses One approach is to put a single fuse in series with each out put This is easy because there is only one fuse per channel to install But if the fuse blows power is re moved to all of the connected loads 3000 1 2000 1500 ja 8 Example 2 Impedance 8 ohms Peak Power 75 W Answer Fuse 1 5 ppl 8 Typically 4 times the continuous average power zn mE ohms FUSE amps tit TT TTT E LOUDSPEAKER IMPEDANCE LOUDSPEAKER RATING PEAK MUSIC POWER watts Fig
26. Studio Reference amplifiers integrate several cutting edge technologies that make them the most accurate reference amplifiers available For example in Stereo mode each channel can actually be treated as a sepa rate amplifier because of its separate high voltage power supplies and ultra low crosstalk Here are some of its many impressive features T Crown s unconventional grounded bridge circuitry delivers incredible voltage swings without using stressful output transistor configurations like other more crouln traditional amplifiers This results in significantly lower distortion and superior reliability Patented ODEP Output Device Emulation Protection circuitry detects and compensates for overheating and overload to keep the amplifier working when others would fail IOC Input Output Comparator circuitry immediately alerts you of any distortion that exceeds 0 05 to provide dynamic proof of distortion free performance P I P Programmable Input Processor connector accepts accessories that tailor your amplifier to suit specific applications Extremely wide dynamic range capable of accurately reproducing 20 bit digital recordings Ultra high damping factor delivers superior loudspeaker motion control for the cleanest tightest chest thumping bottom end you ve ever felt or heard Super low harmonic and intermodulation distortion give your amplifier the best transfer function in the busi
27. The secondaries of T1 are full wave rectified by D1 through D4 D22 and D24 and filtered by large computer grade capacitors A thermal switch embed ded in the transformer protects it from overheating Monolithic regulators provide a regulated 15 volts 5 2 1 Stereo Operation For simplicity the discussion of Stereo operation will refer to only one channel Mono operation will be dis cussed later Please refer to the block diagram in Fig ure 5 1 and the schematics included with this manual The input signal at the phone jack passes directly into the balanced gain stage U104 A When a P I P mod ule is used the input signal first passes through the P I P s circuitry and then to the balanced gain stage The balanced gain stage U104 A causes balanced to single ended conversion using a difference amplifier From there gain can be controlled with the front panel level controls and the input sensitivity switch The error amp U104 C amplifies the difference between the GCrown Studio Reference I amp Hf Professional Studio Amplifiers NMOHS TANNVHO AINO 99A 39A aaao 4 e Fd Avidsia a gt 4 gore 8
28. W MasterCard B C O D Card Number Exp Date Signature ENCLOSE THIS PORTION WITH THE UNIT DO NOT MAIL SEPARATELY
29. aker has been tripped 4 The amplifier s circuit breaker has been tripped ODEP 100 SIGNAL 00909 ON OFF OFF Normal operation for a channel with NO output Possible reasons 1 There is no input signal 2 The input signal level is very low 3 The channel s level control is turned down IOC SIGNAL ON OFF The amplifier is in standby mode Possible reasons 1 The amplifier has just been turned on and is still in the four second turn on delay 2 A module such as an IQ P I P has turned off the channel s high voltage supply 3 The DC low frequency protection circuitry has been activated 4 The fault protection circuitry has been activated 5 The transformer thermal protection circuitry has been activated 6 The overvoltage protection circuitry has been activated SIGNAL O Active ODEP limiting is about to begin or has just ended Possible reasons 1 The amplifier s air filter is blocked and needs to be cleaned 2 There is insufficient cooling because of inadequate air flow or air that is too hot 3 The load impedance for the channel is too low because the output is shorted or the amplifier is driving too many loudspeakers for the selected stereo mono mode 4 The amplifier channel is continuously being driven to very high output levels OO ON ON OFF Channel 2 only The amplifier is in Parallel Mono mode with no output The channel 2 OC indi cator always turns o
30. amplifier and reconnect power AMPLIFIER TOP VIEW FRONT LEFT CORNER END CAP REMOVED AUN MM To remove the handle pull firmly from the side M Fig 4 3 Removing a Handle Studio Reference I amp Professional Studio Amplifiers METER ON OFF SWITCH OFF 4 ON crown Reference I croun OUTPUT LEVEL DYNAMIC RANGE METER MODE SWITCH Fig 4 4 Meter Switches The input sensitivity switch is located inside the amplifier s P I P compartment It is factory set to a fixed voltage gain of 26 dB For standard 1 kHz power into 8 ohms this is equivalent to an input sensitivity of 4 0 volts for the Studio Reference and 2 7 volts for the Studio Reference If needed it can be switched to a sensitivity of 0 775 or 1 4 volts Here is the procedure 1 Turn off the amplifier and disconnect the power cord from the receptacle 2 Remove the P I P module 3 Locate the access hole for the sensitivity switch inside the chassis opening see Figure 4 5 4 Set the switch to the desired position noted on the access hole label 5 Replace the P P module and restore power The ground lift switch located on the back panel can provide isolation between the phone jack input grounds and the AC chassis ground It does not af fect the module s input connectors Slide the SENSITIVITY SWITCH INSIDE ACCESS HOLE This amplifier is equipped with a selectable
31. ass filter in series with the input signal Some ex amples of unbalanced wiring for low pass filters are shown in Figure 3 12 910 ohms To Amp 0056 Source uf GND 6 dB o ictave 3 9 12 dB octave R 600 ohm 015 mp Source T GND 5 mH E b gt To R 600 018 mb Source uf GND 4kHz Note A low source impedance R can be increased to 600 ohms with an appropriate resistor 10 kHz Frequency Fig 3 12 Unbalanced HF Filters 40 kHz 100 kHz For balanced input wiring use an example from Fig ure 3 13 Filters A B and C correspond to the unbalanced filters shown in Figure 3 12 Filter D also incorporates the subsonic filter in Figure 3 11 crouln 470 ohms gt gt Balanced In xe LA Balanced Out 470 ohms 1 8 mH gt G Balanced In oP UA Balanced Out 1 8 mH 2 5 mH 5 00 Balanced In 018 Balanced Out 2 5 mH 0 47 Film 1 8 mH TF gt 015 Balanced In uf Balanced Out l gt 0 47 Film 1 8 mH Fig 3 13 Balanced RF Filters Tip The P I P FX has plenty of space on its circuit board for the addition of input filter circuitry Another problem to avoid is ground loops These are undesired currents that flow in a grounded system and usually cause hum in the output A common source of ground loop problems
32. assively bridge the inputs P I P FXQ makes it easy to connect audio sources that have phono RCA connectors It includes two balanced three pin female XLR connectors and two female phono jacks for quasi balanced or unbalanced operation Q Programmable Input Processor P LP P I P FXT uses balanced 1 1 transformers to isolate the amplifier from the input signal It has balanced female three pin XLR connectors GCrown 24 IF LINE MIC CH 2 INPUTS IF H2 d LEVEL REMOTE LEVEL LINE CH 1 INPUTS Programmable Input Processor adds a switchable balanced low impedance mic input a balanced line level input and a compressor to each channel Remote switching circuitry provides quick and quiet fades from mic to line and back 102 is a two channel module providing equaliza tion based on the BOSE 102 controller Screw terminal plugs provide balanced connections Each input chan nel has an output from the PI P that can be indepen dently configured for output with no processing 102 equalization or 102 equalization with bass cut RPA OVP OV OV ERE 23 SS si Programmable Input Processor P I P RPA adds the features of a 4x2 mixer to your am plifier Its four inputs accept mic or line level input It offers priority switching voice over of each input and remote level control with the RPA RMT Other features include
33. cally resets itself as soon as the trans former cools to a safe temperature If your amplifier is operated within rated conditions it is extremely unlikely that you will ever see it activate transformer thermal protection One reason is that ODEP keeps the amplifier working under very severe conditions Even so higher than rated output levels excessively low impedance loads and unreasonably high input signals can generate more heat in the trans Page 21 croun former than in the output devices This can overheat the transformer and activate its protection system Studio Reference amplifiers are designed to keep work ing under conditions where other amplifiers would fail But even when the limits of a Studio Heference amplifier are exceeded it still protects itself and your invest ment from damage 4 3 4 Circuit Breaker A back panel circuit breaker is provided to prevent ex cessive current draw by the high voltage power sup plies A Studio Reference configured for 100 to 120 VAC has a 30 amp circuit breaker while the 220 to 240 VAC version has a 20 amp circuit breaker A Stu dio Reference configured for 100 to 120 VAC uses a 20 amp circuit breaker and the 220 to 240 VAC ver sion has a 10 amp circuit breaker With rated loads and output levels this breaker should only trip in the incred ibly rare instance of a catastrophic amplifier failure The ODEP system keeps the amplifier safe and operational under most ot
34. controls so a flashing indicator tells you that there is audio in and out of the amplifier Note The signal presence indicators may not report signal presence if the output signal level is too low The dynamic range level meters are five segment output meters that can be set to monitor either the dy namic range or the level of the output signal They are factory set to show dynamic range A switch located behind the front panel is used to select the meter dis play mode see Section 4 4 for complete instructions Indicator Status Amplifier Condition Studio Reference I amp If Professional Studio Amplifiers As dynamic range meters they show each channel s ratio of peak to average power in dB The dynamic range may be low for sources like AM FM radio or low quality recordings Other sources like live music or high quality recordings may be much higher As out put level meters they show how high the output levels are in dB relative to full power At O dB the unit is deliv ering full standard 1 kHz power see Section 6 4 3 Protection Systems Studio Heference amplifiers provide extensive protec tion and diagnostics capabilities Protection systems include ODEP standby mode an AC circuit breaker ODEP 100 SIGNAL OFF OFF There is no power to the amplifier Possible reasons 1 The amplifier s enable switch is off 2 The amplifier is not plugged into the power receptacle 3 The AC mains circuit bre
35. cted then you must make the defective or malfunctioning product available to us free and clear of all liens or other encumbrances The refund will be equal to the actual purchase price notincluding interest insurance closing costs and other finance charges less a reasonable depreciation on the product from the date of original purchase Warranty work can only be performed at our authorized service centers or at the factory We will remedy the defect and ship the product from the service center or our factory within a reasonable time after receipt of the defective product at our authorized service center or our factory All expenses in remedying the defect including surface shipping costs in the United States will be borne by us You must bear the expense of shipping the product between any foreign country and the port of entry in the United States and all taxes duties and other customs fees for such foreign shipments HOW TO OBTAIN WARRANTY SERVICE You must notify us of your need for warranty service not later than ninety 90 days after expiration of the warranty period All components must be shipped in a factory pack which if needed may be obtained from us free of charge Corrective action will be taken within a reasonable time of the date of receipt of the defective product by us or our authorized service center If the repairs made by us or our authorized service center are not satisfactory notify us or our authorized service center im
36. d control the amplifier This is how ODEP keeps the show going with maxi mum power and maximum protection at all times 4 3 2 Standby Mode An important part of a Studio Reference amplifier s pro tection systems is standby mode Standby protects the amplifier during potentially catastrophic conditions It temporarily removes power from the high voltage sup plies to protect the amplifier and its loads Standby mode can be identified using the table in Figure 4 2 Standby mode is activated in five situations First when you turn on the enable switch standby mode is acti vated to provide turn on protection This power up de lay lets other system components settle before any signals are amplified and it provides some power up randomness for multiple units so the system s start up current demands are better distributed over time crouln The amplifier s overvoltage protection circuitry will put both channels into standby when excessive AC mains voltage is detected Studio Reference amplifiers should not be operated with an AC mains voltage of more than 10 over the unit s rated voltage If dangerous subsonic frequencies or direct current DC is detected in the amplifier s output the unit will activate its DC low frequency protection circuitry and put the affected channels in standby This protects the loads and prevents oscillations The amplifier re sumes normal operation as soon as it no longer detects dangerous low fr
37. d current to de liver the undistorted rated power you expect Controls Enable A front panel push button used to turn the ampli fier on and off Level A front panel rotary potentiometer for each channel with 31 detents used to control the output level Stereo Mono A three position back panel switch used to select Stereo Bridge Mono and Parallel Mono mode Page 27 croun Sensitivity A three position switch inside the P P com partment used to select the input sensitivity for both chan nels 0 775 or 1 4 volts for standard 1 kHz power or a 26 dB voltage gain Meter On Off A two position switch behind the front panel used to turn the front panel meters on or off Meter Display Mode A two position switch behind the front panel used to set the display mode for the front panel meters Display modes include dynamic range of the output signal in dB or output levels in dB Ground Lift A two position back panel switch used to isolate the input phone jack and AC chassis grounds Reset A two position back panel switch used to reset the AC mains circuit breaker Indicators Enable This indicator shows the on off status of the unit s low voltage power supply Signal Each channel has a signal indicator that flashes to show audio output IOC Each channel has an OC indicator that flashes if the output waveform differs from the input waveform by 0 05 or more The LEDs act as sensitive distortion indicators to prov
38. damping factor or 3 use more than one cable for each line Options 1 and 2 will require the substitution of new values for cable length or damping factor in the nomograph For option 3 estimate the effective wire gauge by subtracting 3 from the apparent wire gauge every time the number of conductors of equal gauge is doubled So if 10 wire is too large two 13 wires can be substituted or four 16 wires can be used for the same effect SOLVING OUTPUT PROBLEMS High frequency oscillations can cause your amplifier to prematurely activate its protection circuitry The ef fects of this problem are similar to the effects of the RF problem described in Section 3 3 4 To prevent high frequency oscillations follow these guidelines 1 When using long cable runs or when different crouln amplifiers share a common cable tray or jacket use tie wraps to bundle individual conductors so the wires for each loudspeaker are kept close together Do not bundle wires from different amplifiers This reduces the chance of conduc tors acting like antennas to transmit or receive the high frequencies that can cause oscillation Avoid using shielded loudspeaker cable Never tie together input and output grounds Never tie together the output of different amplifiers Keep output cables separated from input cables aoa fF Install a low pass filter in series with each input see Section 3 3 4 7 Install the inout wiring according to
39. de the stereo mono switch to the left as you face the back panel Connect the input signal to channel 1 only The channel 2 input and level control are bypassed in this mode so they should not be used Note It is normal for the channel 2 IOC indicator to stay on in Parallel Mono mode Connect the load to the channel 1 output as shown in Figure 3 7 The positive lead from the loudspeaker connects to the red channel 1 binding post and the negative or ground lead from the loudspeaker con nects to the black channel 1 binding post Finally in stall a jumper wire of at least 14 gauge between the channel 1 and channel 2 red binding posts CAUTION When Parallel Mono wiring is installed do not attempt to operate in Stereo or Bridge Mono mode until the wiring is removed especially the jumper wire Failure to do so will result in high dis tortion and excessive heating ADD A 14 GAUGE OR LARGER JUMPER BETWEEN THE CHANNEL 1 AND 2 RED 4 BINDING POSTS LOUDSPEAKER e STUDIO REFERENCE AMPLIFIER STEREO PARALLEL MONO m BRIDGE MONO CAUTION TURN OFF AMPLIFIER BEFORE CHANGING THIS SWITCH Fig 3 7 Parallel Mono Wiring Page 13 crouJn 3 3 4 Input Connection The balanced inputs have a nominal impedance of 10 K ohms 5 K ohms unbalanced and will accept the line level output of mos
40. dio Amplifiers Vote If two or more channels with 2 the same input ground reference are driven from the same floating source connect only one shield to the Source chassis Floating source 2 wire line cord or battery power INPUT Grounded source Shield not connected at this 3 wire grounded line cord or other ground connection Fig 3 9 Balanced Input Wiring The amplifiers built in 1 input phone jacks can be wired similarly for balanced or unbalanced floating or ground referenced sources They have a standard tip ring sleeve TRS configuration the tip is positive 4 the ring is negative and the sleeve is ground see Figure 3 10 Wiring for various sources follows the XLR wiring examples in Figures 3 8 and 3 9 If you install a P I P module other than the P I P FX P I P FMX or P I P FPX do not connect in put signals to the phone jacks The phone jacks are in parallel with the output of the P P module so the source connected to the phone jacks can feed into the P I P and generate a distortion in the output The phone jacks can still be used as daisy chain outputs to feed the post processed signal from the P I P to the input of other amplifiers If the amplifier will be used in Bridge Mono or Parallel Mono mode be sure to follow the instructions provided in Sections 3 3 2 and 3 3 3 Do not use the channel 2 in
41. equency or DC output Although it is extremely unlikely that you will ever activate the amplifier s DC low frequency protection system im proper source materials such as subsonic square waves or input overloads that result in excessively clipped signals can activate this system The amplifier s fault protection system will put an am plifier channel into standby mode in rare situations where heavy common mode current is detected in the channel s output The amplifier should never output heavy common mode current unless its circuitry is damaged in some way and putting the channel into standby mode helps to prevent further damage The amplifiers transformer thermal protection cir cuitry is activated in very unusual circumstances where the unit s transformer temperature rises to unsafe lev els Under these abnormal conditions the amplifier will put both channels into standby mode The amplifier will return to normal operation after the transformer cools to a safe temperature For more information on trans former thermal protection refer to the section that fol lows 4 3 3 Transformer Thermal Protection All Studio Reference amplifiers have transformer ther mal protection which protects the power supplies from damage under rare conditions where the transformer temperature rises too high A thermal switch embed ded in the transformer removes power to the high volt age power supplies if it detects excessive heat The switch automati
42. er or Crown s Technical Support Group 4 5 Filter Cleaning A dust filter is provided on the amplifier s air intake see Figure 2 1 If this filter becomes clogged the unit will not cool as efficiently as it should and high heat sink temperatures may produce lower than normal output To clean the filter gently pull it away from the front panel and wash it with mild dishwashing detergent and warm water Be sure the filter is dry before you reinstall it Replacement filters may be ordered from the factory Dust filters are not 10096 efficient long term this may require heat sink cleaning by a qualified technician In ternal cleaning information is available from our Tech nical Support Group Page 23 crouJn 5 Technical Information 5 1 Overview Studio Reference amplifiers incorporate several new technological advancements including real time com puter simulation of output transistor stress low stress output stages an advanced heat sink embodiment and the Programmable Input Processor expan sion system Custom circuitry is incorporated to limit temperature and current to safe levels making it highly reliable and tolerant of faults Unlike many lesser amplifiers it can operate at its voltage and current limits without self de structing Studio Reference amplifiers are protected against all common hazards that plague high power amplifiers in cluding shorted open or mismatched loads over loaded power sup
43. escription of ODEP see Section 4 3 1 A channel s ODEP indicator also turns off if its high voltage power supply is put in standby mode or the amplifier s circuit breaker is tripped The standby mode is activated if DC or heavy common mode cur rent is detected in the output if the transformer thermal protection system is activated if a like the Smart Amp IQ P I P is used to shut down a high voltage sup ply or if excessive AC mains voltage is detected For more information see Section 4 3 and the table in Fig ure 4 2 The yellow IOC indicators act as sensitive distortion meters to provide proof of distortion free performance The OC Input Output Comparator circuitry compares the incoming signal s waveform to that of the output Any difference between the two is distortion The OC indicators flash if there is a difference of 0 05 or more The OC indicators also show input overload by flashing brightly with a half second hold delay It is nor mal for them to light momentarily when the amplifier is first turned on Note The channel 2 IOC indicator will stay on in Parallel Mono mode Also an IOC indicator will stay on in abnormal situations where a high voltage power supply is temporarily put in standby mode Page 19 croun The green signal presence indicators flash synchro nously with the amplifier s output signal The signal de tector is connected to the signal path after the input gain stages and level
44. get what you pay for Minimum Power Notes All minimum power specifications are based on 0 5 regulated AC mains with THD of less than 1 kHz 20Hz 20kHz 1 1 20Hz 20kHz 1 096 and an ambient room temperature of 70 F 21 C Standard EIA power RS 490 is not shown here because it is identical to FTC Continuous Average Power Maximum Average FTC Continuous Average Stereo Mono 0 1 THD N 0 1 THD N 0 05 THD N 0 1 THD Noise Mode See note 1 Seenote2 See note 3 See note 4 Stereo both channels driven 1 1 kHz sine wave is presented to the ampli fier and the output monitored for nonlinear dis tortion The level is increased until THD reaches 0 1 At this point average power per channel is reported Bridge Mono balanced output 120 VAC 60 Hz Parallel Mono 2 Asine wave is presented to the amplifier over the range from 20 Hz to 20 kHz and the output monitored for nonlinear distortion The level at each frequency is increased until THD reaches 0 1 At this point average power per chan nel is reported Stereo both channels driven Bridge Mono balanced output 100 VAC 50 Hz 3 A 1 kHz sine wave is presented to the ampli fier and the output monitored for nonlinear dis tortion The level is increased until THD reaches 0 05 At this point average power per channel is reported Parallel Mono Stereo both channels driven
45. her can also cause feedback oscil lation from the load current flowing in the loop To avoid this problem use proper grounding isolate the inputs and isolate other common AC devices When using the input phone jacks the signal grounds can be isolated from the AC mains ground with the ground lift switch located on the amplifier s back panel see Fig ure 2 2 and Section 4 4 3 3 5 Output Connection Consider the rated power handling capacity of your load before connecting it to the amplifier Crown is not liable for damage incurred at any time due to overpow ering Fusing loudspeaker lines is highly recom mended see Section 3 3 6 Also please pay close attention to Section 4 1 Precautions You should always install loudspeaker cables of suffi cient gauge wire thickness for the length used The resistance introduced by inadequate output wiring will reduce the amplifier s power to and motion control of the loudspeakers The latter problem occurs because Use Good Connectors 1 Male connectors on loudspeaker cables should not be exposed to prevent possible short circuits 2 Connectors which might accidentally cause the two channels to be tied together when making and breaking connections should not be used A common example is the standard three wire stereo phone plug 3 Connectors which can be plugged into AC power receptacles should never be used 4 Connectors having low current carrying capacity should not be
46. her severe conditions The breaker can also trip in situations where extremely low impedance loads and high output levels result in current draw that exceeds the breaker s rating Again this should only be possible when operating outside rated conditions like when the amplifier is used to drive a 1 ohm load or when an input signal is clipped severely 4 4 Controls The front panel enable switch is used to turn the ampli fier on and off If you ever need to make any wiring or installation changes don t forget to disconnect the power cord first Please follow these steps when first turning on your amplifier 1 Turn down the level of your audio source For example set your mixer s volume to 0 off 2 Turn down the amplifier s level controls 3 Turn on the enable switch The enable indicator be side the switch should glow During the four second turn on delay that immediately follows the indica tors will flash as described in Figure 4 2 After the delay the ODEP indicators should come on with full brilliance and the OC and signal presence indica tors should function normally 4 After the turn on delay turn up your source to the maximum desired level 5 Turn up the amplifier s level controls until the maxi mum desired sound level is achieved 6 Turn down the level of your audio source to its normal range Page 22 Studio Reference I 8 IM Professional Studio Amplifiers Each of the front panel le
47. ide proof of distortion free performance In Parallel Mono mode the channel 2 OC light stays on ODEP Each channel has ODEP indicator that shows the channel s reserve energy status Normally the LEDs are brightly lit to show that reserve energy is available In the rare event that a channel has no reserve its indicator will dim in proportion to ODEP limiting An ODEP indicator may also turn off under other more unusual circum stances see Section 4 3 Dynamic Range Level Meter Each channel has a five segment meter that displays either the dynamic range of the output signal in dB or the output level in dB From the factory the amplifier is set to display dynamic range As dynamic range meters they show the ratio of the peak to average power of each channel As output level meters they show how high the output levels are relative to stan dard 1 kHz power Input Output Input Connector Two balanced phone jacks on the back panel and two balanced three pin XLR connectors on the factory installed P I P FX see Section 8 for infor mation on optional P P modules Input Impedance Nominally 10 K ohms balanced Nominally 5 K ohms unbalanced Page 28 Studio Reference I 8 IM Professional Studio Amplifiers Input Sensitivity Settings include 0 775 volts or 1 4 volts for standard 1 kHz power or a 26 dB voltage gain see Section 4 4 for more information Output Connectors Two sets of color coded 5 way binding po
48. ifier 1 kHz 1 kHz can function well with AC Stereo mains voltages up to 10 over both channels the specified line voltage With EE driven overvoltage conditions your 4 amplifier may be capable of c3 Bridge Mono delivering instantaneous S balanced output power levels up to 20 S greater than the specifications Parallel Mono in the matrix 1 single cycle sine wave is Stereo presented to the amplifier both channels and monitored for nonlinear driven distortion The average Bridge Mono power during the burst is lt balanced output reported Loudspeakers must be able to withstand this level if they are to be Parallel Mono safely used with this ampli St fier both mance 2 40 millisecond sine wave driven burst 10 percent duty cycle is presented to the amplifier Bridge Mono and monitored for nonlinear balanced output distortion Average power during the burst is reported Parallel Mono This power level is a mea surement of the amplifier s maximum transient power that can be perceived by the human ear 240 VAC 50 Hz Fig 6 3 Studio Reference Maximum Power Matrix Page 31 crouJn Page 32 Studio Reference I 8 IM Professional Studio Amplifiers Studio Reference Maximum Power Watts Stereo Mono Mode Stereo both channels driven Single Cycle Tone Burst 0 05 Distortion Noise See note 1 40 Millisecond Tone Burst 0 05
49. ilters have corner frequencies of 24 28 32 and 36 Hz FTE h h ego IE CH 2 INPUT CH 1 INPUT Programmable Input Processor P LP includes all P I P FXT features and adds 12 dB octave RFI filters variable 18 dB octave high pass filters and 6 dB octave 3 KHz shelving networks for con stant directivity horn equalization Screw terminal plugs are provided for input IQ P I P AP integrates the amplifier into Crown s pat ented Q System The IQ System provides centralized computer control of 1 to 2 000 amplifiers Each ampli fier channel can be monitored and controlled from an inexpensive personal computer Any combination of mic and line level signals can also be mixed and routed with optional 6 SMX 6 and AMB 5 mixer multiplex ers and the MRX series matrixers IQ P I P AP Smart Amp offers the monitoring and control features of the IQ P I P AP plus the ability to function as a stand alone unit as part of the Q System s distributed intelligence Features include a smooth output limiter for transparent loudspeaker pro tection power supply gates for energy savings ODEP conservation which protects the output devices with precision input signal control interrupt driven report ing that lets you define error conditions and config urable short detection Programmable INPUT INPUT Input Processor P LP P I P CLP is designed to detect and prevent overload I
50. ind mounting surface and 2 75 inch 7 cm protru sion in front of mounting surface Approximate Weight Center of gravity is about 6 inches 15 2 cm behind the front mounting surface Studio Reference 60 pounds 11 ounces 27 6 kg net 74 pounds 3 ounces 33 7 kg shipping weight Studio Reference 56 pounds 2 ounces 25 5 kg net 69 pounds 10 ounces 31 6 kg shipping weight Studio Reference 14 IM Professional Studio Amplifiers crown Crown specifications are guaranteed for three years In an effort to provide you with as much information as possible about the high power producing capabilities of your amplifier we have created the following power matrices Minimum Guaranteed Power Specifications Crown s minimum power specifications represent the absolute smallest amount of output power you can expect from your amplifier when it is driven to full output under the given conditions Some spaces in each matrix may be left blank because the same guarantee is not provided for those conditions however your amplifier will perform well under all conditions listed in each matrix When measuring power 0 1 THD appears to be the industry standard for distortion Two of the maximum average power specifications shown in each minimum power matrix are measured at 0 1 THD so you can easily compare Crown specifications to those of other manufacturers But this high level of distortion actually allows for some clipping which is undes
51. ional Studio Amplifiers AR 4m BLOWER FLOW O OPTION 2 RACK EQUIPMENT RACK SIDE VIEW AIR BLOWER FLOW OPTION 1 Hp m Fig 3 4 Proper Air Flow with a Hack Mounted Blower mounting piles of power cords clogged dust filters and closed rack doors Mount your amplifier to allow suffi cient air flow into the front intake out the side exhaust vents and out the back of the rack An air flow restriction like a pile of power cords can simply be moved out of the way Airfilters should be cleaned using the procedure in Section 4 5 If rack doors arethe problem you can leave them open remove them or install a grille If you install a grille we recommend using a wire grille because per forated panels restrict air flow by at least 4096 If your ODEP indicators still dim under demanding con ditions we recommend that you check the table of indicator states in Figure 4 2 to eliminate other condi tions that could be the source of the problem If it is clear that the amplifier does not have sufficient air flow STEREO MODE THAM CHANNEL 1 CHANNEL 2 crouln you may want to install supplemental cooling like a rack mounted blower or an air conditioner A squirrel cage blower can be installed at the bottom of the rack so it blows outside air into the space be tween the door and the front of the amplifiers This will pressurize the chimney behind the door Figure 3 4 Option 1 The blower should no
52. irable Because of this a maximum average power specification at 0 05 THD is included in each minimum power matrix which represents non clipped conditions Also power at 0 02 THD is provided in the preceding specifications Although most manufacturers do not give power specifications at 0 05 or 0 02 THD we encourage them to provide these specifications so you will have a more realistic representation of the way amplifiers should be used in the real world without a clipped output signal Many manufacturers publish power specs with a tolerance of 1 dB or worse This means their amplifier can deviate more than 20 in output A 100 watt amplifier would meet their specification if it only produced 79 4 watts Other manufacturers qualify their specs by saying they are typical subject to manufacturing tolerances single channel driven or that they are specified with fuses bypassed Each of these statements effectively removes any performance guarantee In fact some manufacturers use these tactics to generate large power numbers and they don t even print a disclaimer We take a different approach at Crown our amplifiers are guaranteed to meet or exceed their specifications for three years Further because our published specs are set below our in house mea surements you can expect every Crown 7 amplifier to exceed its published minimum Studio Reference Minimum Guaranteed Power Watts power specs We believe you should
53. is in effect only for failure of a new Crown product which occurred within the Warranty Period It does not cover any product which has been damaged because of any intentional misuse accident negligence or loss which is covered under any of your insurance contracts This Crown Warranty also does not extend to the new Crown product if the serial number has been defaced altered or removed WHAT THE WARRANTOR WILL DO We will remedy any defect regardless ofthe reason forfailure exceptas excluded by repair replacement or refund We may not elect refund unless you agree or unless we are unable to provide replacement and repairis not practical or cannot be timely made If a refundis elected then you must make the defective or malfunctioning product available to us free and clear of all liens or other encumbrances The refund will be equal to the actual purchase price not including interest insurance closing costs and other finance charges less a reasonable depreciation on the product from the date of original purchase Warranty work can only be performed at our authorized service centers We will remedy the defect andshipthe productfrom the service center within a reasonable time after receipt of the defective product at our authorized service center All expenses in remedyingthe defect including surface shipping costs to the nearestauthorized service center will be borne by us You mustbearthe expense of alltaxes duties and other custom
54. is the placement of input cables parallel to power cables or near power transformers The magnetic field that surrounds these conductors can induce the 50 or 60 Hz alternating current into your input cables To prevent this type of ground loop it is always a good idea to locate input cables away from Input Wiring Tips 1 Use only shielded cable Cables with higher density shields are better Spiral wrapped shield is not recommended 2 When using unbalanced lines keep the cables as short as possible Avoid cable lengths greater than 10 feet 3 meters 3 Do not run signal cables together with high level wiring such as loudspeaker wires or AC cords This reduces the chance of hum or noise being induced into the input cables 4 Turn the entire system off before chang ing connections Turn level controls down before powering the system back up Crown is not liable for damage incurred when any transducer or component is overdriven Page 15 croun power cables and power transformers We also recom mend using shielded or twisted pair wire With loose wires use tie wraps to bundle together each pair of in put wires This helps reduce magnetically induced current by minimizing the cross sectional area be tween conductors that could bisect the magnetic field Ground loops often occur when the input and output grounds are tied together DO NOT CONNECT THE INPUT AND OUTPUT GROUNDS TOGETHER Tying the grounds toget
55. lanced circuit then develops a voltage to drive the bridge bal anced output stage This results in the Vcc supply hav ing exactly one half of the output voltage added to its quiescent voltage Bias servo Q300 sets the quiescent current point for the bridge balanced output stage The protection mechanisms that affect the signal path are implemented to protect the amplifier under real world conditions These conditions are high instanta neous current excessive temperature and output device operation outside safe conditions Q107 and Q108 act as a conventional current limiter sensing current in the output stage When output cur rent at any instant exceeds the design criteria the limit ers remove drive from the LVAs thus limiting current in the output stage to a safe level To further protect the output stages the patented ODEP circuitry is used It produces an analog output proportional to the always changing safe operating area of the output transistors This output controls the translator stage previously mentioned removing any further drive that may exceed the safe operating area of the output stage Thermal sensor 5100 gives the ODEP circuit vital infor mation on the operating temperature of the heat sink on which the output devices are mounted Should the amplifier fail in such a way that would cause Page 26 Studio Reference I 8 IM Professional Studio Amplifiers DC across the output leads the DC low frequency pr
56. lowing equation converts power draw in watts to current draw in amperes AC Mains Power e Amplifier efficiency at standard 1 kHz power is Current Draw Draw watts estimated to be 65 amperes AG Maie c E Quiescent power draw is 90 watts an almost negligible amount for full power calculations Quiescent thermal dissipation equals 307 btu hr at 90 watts Duty cycle takes into account the typical crest factor for a particular type of source material Duty cycle of pink noise is 50 Duty cycle of highly compressed rock n roll midrange is 4096 The power factor constant of 0 83 is needed to compensate for the difference in phase between in the AC mains voltage and current The following equation was used to calculate thermal dissipation The constant 0 35 is inefficiency 1 00 0 65 and the factor 3 415 converts watts to btu hr Thermal dissipa tion in btu is divided by the constant 3 968 to get kcal If Thermal Dissipation btu hr Total output power with all Duty channels driven watts Cycle Amplifier Efficiency 65 x 35 Quiescent Power 4 Draw 90 watts X3 415 Duty cycle of uncompressed rock n roll is 30 you plan to measure output power under real world Duty cycle of background music is 20 conditions the following equation may be helpful e Duty cycle of continuous speech is 10 Thermal f Total output power with all Dut E Dissipation channels dti
57. mediately DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES YOU ARE NOT ENTITLED TO RECOVER FROM US ANY INCIDENTAL DAMAGES RESULTING FROM ANY DEFECT IN THE NEW CROWN PRODUCT THIS INCLUDES ANY DAMAGE TO ANOTHER PRODUCT OR PRODUCTS RESULTING FROM SUCH A DEFECT SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATIONS OF INCIDENTAL OR CONSEQUENTIAL DAMAGES SO THE ABOVE LIMITATION OR EXCLUSION MAY NOT APPLY TO YOU WARRANTY ALTERATIONS No person has the authority to enlarge amend or modify this Crown Warranty This Crown Warranty is not extended by the length of time which you are deprived of the use of the new Crown product Repairs and replacement parts provided under the terms of this Crown Warranty shall carry only the unexpired portion of this Crown Warranty DESIGN CHANGES We reserve the right to change the design of any product from time to time without notice and with no obligation to make corresponding changes in products previously manufactured LEGAL REMEDIES OF PURCHASER THIS CROWN WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS YOU MAY ALSO HAVE OTHER RIGHTS WHICH VARY FROM STATE TO STATE No action to enforce this Crown Warranty shall be commenced later than ninety 90 days after expiration of the warranty period THIS STATEMENT OF WARRANTY SUPERSEDES ANY OTHERS CONTAINED IN THIS MANUAL FOR CROWN PRODUCTS Telephone 219 294 8200 Facsimile 219 294 8301 9 90 The information furnished in this manual does not include all
58. menal damping factor of 20 000 from 10 to 200 Hz in Stereo mode with an 8 ohm load In contrast most other amplifiers have a damping factor rating of 200 or less Higher damping factors yield lower distortion and greater motion control over the loudspeakers To give you a basis for comparison effective damping factors for commercial applications typically run between 50 and 100 Higher damping factors may be desirable for live sound but long cable lengths often limit the highest damping factor that can be achieved practically Under these circumstances Crown s Q System is often used so amplifiers can be easily monitored and controlled when they are located very near the loudspeakers In record ing studios and home hi fi a damping factor of 500 or more is very desirable 3 Draw a line through the two points with a pencil and continue until it intersects the Source Resistance line 4 On the 2 Cond Cable line mark the length of the cable run 5 Draw a pencil line from the mark on the Source Resis tance line through the mark on the 2 Cond Cable line and on to intersect the Annealed Copper Wire line 6 The required wire gauge for the selected wire length and damping factor is the value on the Annealed Copper Wire line Note Wire size increases as the AWG gets smaller 7 f the size of the cable exceeds what you want to use 1 find a way to use shorter cables like using the Q Sys tem 2 settle for a lower
59. most efficient air flow and support If the rack will be transported we recommend that you fasten the amplifier s back panel securely to the rack to help support the unit s weight crown Refeietic FRONT VIEW 17 3 cm I 19 in 48 3 cm SIDE VIEW 16in 40 6 cm Fig 3 1 Mounting Dimensions Before proceeding make sure the meter switches are set to your liking The front panel assembly must first be removed to change these switches so it is easier to do before the unit is mounted see Section 4 4 By now you may be looking for rack ears The rack ears are covered by two attractive end caps which are held in place by phillips screws see Figure 3 2 To use the rack ears remove the screws and lift off the caps With sufficient side clearance you can reinstall the end caps once the amplifier is mounted in the rack FM j Fig 3 2 Removing an End Cap Page 10 Studio Reference I amp If Professional Studio Amplifiers 3 2 Cooling Your amplifier has an internal variable speed fan that is controlled to match the unit s real time cooling needs With proper installation and typical studio use the fan may never need to run For best results you should fa miliarize yourself with its cooling requirements Here are some tips to help keep your amplifier cool First never block the amplifier s front or side air vents If the amplifier is rack mounted
60. n invented ODEP to solve two long standing problems in amplifier design to prevent amplifier shut down during demanding operation and to increase the efficiency of output circuitry To do this Crown established a rigorous program to measure the safe operating area SOA of each output transistor before installing it in an amplifier Next Crown designed intelligent circuitry to simulate the in stantaneous operating conditions of the output transis tors Its name describes what it does Output Device Emulation Protection or ODEP In addition to simulating the operating conditions of the output transistors it also compares their operation to their known SOA If ODEP sees that more power is about to be asked of the output transistors than they are capable of delivering under he present conditions ODEP immediately limits the drive level until it falls within the SOA Limiting is pro portional and kept to an absolute minimum only what is required to prevent output transistor damage This level of protection enables Crown to increase out put efficiency to never before achieved levels while greatly increasing amplifier reliability The on board intelligence is monitored two ways First the amplifiers ODEP indicators show whether the unit is functioning correctly or if ODEP is limiting output Second ODEP data is fed to the amplifier s internal P I P connector so advanced P I P modules like the IQ P I P can use it to monitor an
61. n the high side NPN and low side PNP stage while synchronously decreasing conductance of the high side PNP and low side NPN Page 24 Studio Reference I 8 IM Professional Studio Amplifiers The two channels may be used together to double the voltage Bridge Mono or the current Parallel Mono presented to the load This feature gives you the flex ibility to maximize power available to the load A wide bandwidth multiloop design is used for state of the art compensation This produces ideal behavior and results in ultra low distortion values Aluminum extrusions are used widely for heat sinks in power amplifiers due to their low cost and reasonable performance However measured on a watts per pound or watts per volume basis the extrusion tech nology doesn t perform nearly as well as the heat sink technology developed for Studio Reference amplifiers Our heat sinks are fabricated from custom convoluted fin stock that provides an extremely high ratio of area to volume or area to weight All power devices are mounted directly to the heat sinks which are also elec trically at the Vcc potential Electrifying the heat sinks improves thermal performance by eliminating the insu lating interface underneath the power devices The chassis itself is even used as part of the thermal circuit to maximize utilization of the available cooling re sources 5 2 Circuit Theory Power is provided by low field toroidal power trans former T1
62. n when the amplifiers stereo mono switch is moved to the Parallel Mono position SIGNAL 000 ON Active show that there is audio output Normal operation for a channel with audio output The ODEP indicator will remain at full intensity to show that there is reserve thermal dynamic energy and the signal presence indicator will flash to e 00 ON Active ODEP limiting has been activated Possible reasons 1 The amplifier s air filter is blocked and needs to be cleaned 2 There is insufficient cooling because of inadequate air flow or air that is too hot 3 The load impedance for the channel is too low because the output is shorted or the amplifier is driving too many loudspeakers for the selected stereo mono mode 4 The amplifier channel is continuously being driven to very high output levels SIGNAL Q Q ON Active The channel s output is exceeding 0 05 distortion The input signal level is too high and OC is reporting either an input overload or output clipping OR Channel 2 only The amplifier is Parallel Mono mode and has output The channel 2 OC indi cator always turns on when the amplifiers stereo mono switch is moved to the Parallel Mono position Fig 4 2 Studio Reference Indicator States Page 20 Studio Reference I amp Professional Studio Amplifiers and transformer thermal protection These systems will prevent amplifier damage in virtually any situation 4 3 1 ODEP Crow
63. ness Two mono modes Bridge Mono and Parallel Mono for driving a wide range of load impedances Custom designed tape wound low noise toroidal supplies with extremely high power density High voltage headroom and high current headroom provide energy reserves that make it easy to drive low impedance loads and highly reactive loads to full power Full protection against shorted outputs mismatched loads general overheating DC and high frequency overloads Full overvoltage and internal fault protection Indicators include Enable ODEP Signal Presence and the Dynamic Range Level meter Balanced phone jacks and XLR connectors are pro vided for input Two pair of 5 way binding posts per channel are provided for versatile output connection Ground lift switch isolates the AC power and phone jack audio grounds Efficient heat sinks and a self contained on demand infinitely variable forced air cooling system prevents overheating and prolongs component life Internal three position input sensitivity switch provides settings of 0 775 volts and 1 4 volts for standard 1 kHz power and 26 dB gain Mounts in a standard 19 inch 48 3 cm equipment rack or units can be stacked directly on top of each other Three year No Fault full warranty completely protects your investment and guarantees its specifications Page 7 Crown Refetence I Studio Reference I amp If Professional Studio Amplifiers
64. nse Typical Common Mode Rejection Typical Grosstalk i Studio Reference Power Draw Current Draw and Thermal Dissipation at Various Duty Cycles Studio Reference Power Draw Current Draw and Thermal Dissipation at Various Duty Cycles Installing a P I P Module crouln Page 5 crown Studio Reference I 8 If Professional Studio Amplifiers UDIO Gcrown Reference Fig 1 1 Studio Reference Amplifier Unpacking Instructions Please unpack and inspect your new amplifier for any damage that may have occurred during transit If damage is found notify the transportation com pany immediately Only you the consignee may a claim for shipping damage Crown will be happy to cooperate fully as needed Save the ship ping carton as evidence of damage for the shipper s inspection Even if the unit arrived in perfect condition as most do save all packing materials so you will have them if you ever need to transport the unit NEVER SHIP THE UNIT WITHOUT THE FACTORY PACK Page 6 Studio Reference I 8 IM Professional Studio Amplifiers 1 Welcome The stunning realism you will experience when listen ing to a Crown Studio Reference amplifier will redefine your expectations The evolution of this studio standard ushers in a ne
65. nted Proper Air Flow with a Rack Mounted Blower Stereo WING sts ER tret nc Bridge Mono 0 2 Parallel Mono Wiring 222222 Unbalanced Input 0 222222 5 Balanced Input 2222 Balanced and Unbalanced Phone Plugs Subsonic Filter Capacitors Unbalanced FF Filters Balanced HF Filters Wire Size Nomograph 222 2 2 m Inductive Load Transformer Loudspeaker Fuse Nomograph Ke E Studio Reference Indicator Removing a Handle 2 2 2 2 Meter SWiIGKES Input Sensitivity and Ground Lift Switches Circuit Block Diagram 2 9 Studio Reference Minimum Power Matrix Studio Reference Minimum Power Matrix Studio Reference Maximum Power Matrix Studio Reference Maximum Power Matrix Typical Frequency Response Typical Damping Typical Output Impedance Typical Phase Respo
66. o tection circuit senses this on the negative feedback loop and shuts down the power supply until the DC is removed 5 2 2 Bridge Mono Operation By setting the back panel stereo mono switch to Bridge Mono the user can convert the amplifier into a bridged single channel amplifier With a signal ap plied to the channel 1 input jack and the load con nected across the two channels red 5 way binding posts twice the voltage can be output The channel 1 output feeds the channel 2 error amp U204 C Because there is a net inversion channel 2 output is out of polarity with channel 1 This produces twice as much voltage across the load Each channel s protection mechanisms work independently if a fault occurs 5 2 3 Parallel Mono Operation With the stereo mono switch set to Parallel Mono the output of channel 2 is paralleled with the output of channel 1 A suitable jumper capable of handling high current must be connected across the red 5 way posts to gain the benefits of this mode of operation The signal path for channel 1 is the same as previously discussed except channel 1 also drives the output stage of channel 2 The channel 2 balanced input error amp translators and LVAs are disconnected and no longer control the channel 2 output stage Disconnect ing the front end stages from the channel 2 output causes the channel 2 IOC circuit to note that the input waveform which is not present does not match the output wavef
67. operly connect the output wiring as shown in Figure 3 5 Each output channel has two sets of binding posts to make it easier for you to con nect multiple loudspeaker cables to each channel Be sure to observe correct loudspeaker polarity see Fig ure 3 5 and be careful not to short the outputs CAUTION In Stereo mode never tie an amplifier s outputs together directly and never parallel them with the output of another amplifier Such connec tions do not result in increased output power but may activate the protection circuitry to prevent overheating 3 3 2 Bridge Mono Operation Bridge Mono mode is used to drive loads with a total impedance of at least 4 ohms see Parallel Mono if the load is less than 4 ohms Wiring for Bridge Mono mode is different from the other modes and requires special attention First turn off the amplifier Then se lect Bridge Mono mode by sliding the stereo mono switch to the right as you face the back panel Both outputs receive the channel 1 input signal but chan nel 2 is inverted so it can be bridged with channel 1 Do not use the channel 2 input or signal quality will be THU CHANNEL 1 MIXER DO NOT USE THE CHANNEL 2 INPUTS LOUDSPEAKER CJ DO NOT USE ARA 00 THE BLACK BINDING 2 STUDIO REFERENCE AMPLIFIER STEREO POSTS PARALLEL BRIDGE MONO MONO CAUTION
68. orm which is driven by the channel 1 in put signal This activates the channel 2 OC indicator any time the amplifier is switched into Parallel Mono mode The channel 2 output stage and protection mechanisms are also coupled through S1 and functi as one ION In Parallel Mono mode twice the current of one chan nel alone be obtained Because the channel 2 ODEP circuit is coupled through S1 this gives added protection if a fault occurs in the channel 2 output stage The ODEP circuit of channel 2 will limit the out put of both output stages by removing the drive from the channel 1 translator stages Studio Reference I amp Professional Studio Amplifiers 6 Specifications The following applies to units in Stereo mode with 8 ohm loads and an input sensitivity of 26 dB gain unless otherwise specified Low Distortion 1 kHz Power refers to maximum average power in watts at 1 kHz with 0 0296 THD and noise Standard 1 kHz Power refers to maximum average power in watts at 1 kHz with 0 196 THD and noise Full Bandwidth Power refers to maximum average power in watts from 20 Hz to 20 kHz with 0 196 THD and noise Performance Frequency Response 0 1 dB 20 Hz to 20 kHz at 1 watt see Figure 6 5 Phase Response 5 to 15 degrees from 20 Hz to 20 kHz at 1 watt see Figure 6 8 Signal to Noise A weighted Studio Reference Greater than 120 dB below rated full bandwidth power Studio Reference Greater than 1
69. plies excessive temperature chain destruction phenomena input overload and high frequency blowups The unit protects loudspeak ers from input and output DC as well as turn on and turn off transients Real time computer simulation is used to create an analogue of the junction temperature of the output tran sistors hereafter referred to as the output devices Current is limited only when the device temperature becomes excessive and only by the minimum amount necessary This patented approach maximizes the available output power and eliminates overheat ing the major cause of device failure Crown also invented the four quadrant topology used in the output stages of each Studio Reference ampli fier see Figure 5 1 This special circuitry is called the grounded bridge It makes full use of the power supply by delivering peak to peak voltages to the load that are twice the voltage seen by the output devices As its name suggests the grounded bridge topology is referenced to ground Composite devices are con structed to function as gigantic NPN and PNP devices to handle currents which exceed the limits of available devices Each output stage has two composite NPN and two composite PNP devices The devices connected to the load are referred to as high side NPN and PNP and the devices connected to ground are referred to as low side NPN and PNP Positive current is delivered to the load by increasing conductance simultaneously i
70. put in either mono mode EN gt e BALANCED SHIELD UNBALANCED gt SHIELD Fig 3 10 Balanced and Unbalanced Phone Plugs Studio Reference I amp Professional Studio Amplifiers SOLVING INPUT PROBLEMS Sometimes large subsonic subaudible frequencies are present in the input signal These can damage loudspeakers by overloading or overheating them To attenuate such frequencies place a capacitor in series with the input signal line The graph in Figure 3 11 shows some capacitor values and how they affect the frequency response of a Studio Reference amplifier Use only low leakage capacitors 4 2 7 Our 0 E 2 Tup 0 1Hz 10Hz 100 Hz Frequency 1 kHz Fig 3 11 Subsonic Filter Capacitors 10 kHz Another problem to avoid is large levels of radio fre quencies or RF in the input signal Although high RF levels may not pose a threat to the amplifier they can burn out tweeters or other loads that are sensitive to high frequencies Extremely high RF levels can also cause your amplifier to prematurely activate its protec tion circuitry resulting in inefficient operation RF can be introduced into a signal by local radio stations and from the bias signal of many tape recorders To pre vent high levels of input RF install an appropriate low p
71. raw and Thermal Dissipation at Various Duty Cycles Page 37 crouJn 8 Accessories 8 1 P I P Modules One advantage of Studio Reference amplifiers is the ability to customize them using Programmable In put Processor modules Each amplifier is equipped with an edge card connector inside the back panel compartment The modules install easily gt PANEL 9 Gr AMPLIFIER Fig 8 1 Installing a P I P Module WARNING Disconnect power to the amplifier when in stalling or removing a PI P module Here are some of the available modules Programmable Input Processor P LP P I P AMCb unites many features of the P I P XOV and It offers a variable 4th order Linkwitz Riley crossover and an OC driven variable threshold com pressor In addition it provides constant directivity horn equalization and filter assisted vented box equaliza tion Biamping and triamping capabilities are provided via XLR connectors Programmable Input Processor P LP P I P EDCb combines a sophisticated error driven com pressor and smooth limiter with a subsonic filter for each channel The compressors have adjustable attack and release times and can be set to track each other The Page 38 Studio Reference I 8 IM Professional Studio Amplifiers compressors activate when a signal will clip the input an OC error occurs or the output exceeds the selected threshold The subsonic f
72. s fees whentransporting the product HOW TO OBTAIN WARRANTY SERVICE You must notify us of your need for warranty service not later than ninety 90 days after expiration of the warranty period All components must be shipped in a factory pack Corrective action will be taken within a reasonable time of the date of receipt of the defective product by our authorized service center If the repairs made by our authorized service center are not satisfactory notify our authorized service center immediately DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES YOU ARE NOT ENTITLED TO RECOVER FROM US ANY INCIDENTAL DAMAGES RESULTING FROM ANY DEFECT IN THE NEW CROWN PRODUCT THIS INCLUDES ANY DAMAGE TO ANOTHER PRODUCT OR PRODUCTS RESULTING FROM SUCH A DEFECT WARRANTY ALTERATIONS No person has the authority to enlarge amend or modify this Crown Warranty This Crown Warranty is not extended by the length of time which you are deprived of the use of the new Crown product Repairs and replacement parts provided under the terms of this Crown Warranty shall carry only the unexpired portion of this Crown Warranty DESIGN CHANGES We reserve the right to change the design of any product from time to time without notice and with no obligation to make corresponding changes in products previously manufactured LEGAL REMEDIES OF PURCHASER No action to enforce this Crown Warranty shall be commenced later than ninety 90 days after expiration of the warranty
73. sed to trip and reset the AC mains circuit breaker see Section 4 3 4 J Power Cord For 120 VAC 60 Hz North American units the Studio Heference includes a 10 AWG power cord and NEMA plug and the Studio Reference includes a 12 AWG cord and NEMA 5 15P plug Other units are shipped with an appropriate power cord and plug K P I P Module The standard P I P FX input module is provided with your amplifier It provides female XLR input connectors Each pair of XLR and phone jack connectors is wired in parallel so the unused connector can be used as a daisy chain output to connect a source to multiple am plifiers Other P P modules can be used in place of the P I P FX to provide additional features that customize your amplifier for different applications see Section 8 for available P I P modules L Balanced XLR Inputs A balanced three pin female XLR connector is provided on the P I P FX K for input to each channel Caution Do not use the channel 2 input in either mono mode M Output Connectors Two pairs of versatile 5 way binding posts are provided for the output of each channel so multiple loudspeakers can be connected easily They accept banana plugs spade lugs or bare wire N Stereo Mono Switch This switch is used to select one of three operating modes Stereo mode is used for normal two channel operation Bridge Mono mode is used to drive a single channel with a load impedance of at least
74. sts for each channel for connecting banana plugs spade lugs or bare wire Output Impedance Less than 10 milliohms in series with 2 5 microhenries DC Output Offset Shorted input 2 millivolts Output Signal Stereo Unbalanced two channel Bridge Mono Balanced single channel Channel 1 con trols are active channel 2 should be turned down Parallel Mono Unbalanced single channel Channel 1 controls are active channel 2 is bypassed Protection If unreasonable operating conditions occur the protec tion circuitry limits the drive level to protect the output stages especially in the case of elevated temperature Transformer overheating will result in a temporary shut down Controlled slew rate voltage amplifiers protect the unit against RF burnouts Input overload protection is fur nished at the amplifier input to limit current Turn On The four second turn on delay prevents dan gerous turn on transients To change the turn on delay time contact Crown s Technical Support Group Construction Steel chassis with durable black finish aluminum front panel with super gloss Imron finish Lexan overlay and a specially designed flow through ventilation system from front to side panels Cooling Convection cooling with assistance from the computerized on demand proportional cooling fan Dimensions Standard 19 inch 48 3 cm rack mount width EIA RS 310 B 7 inch 17 8 cm height 16 inch 40 6 cm depth beh
75. t blow air into or take air out of the space behind the amplifiers For racks without a front door you can evacuate the rack by mounting the blower at the top of the rack so air blows out the back Figure 3 4 Option 2 You can estimate a rack s required air flow by adding each unit s maxi mum air flow rating The Studio Reference and can each move up to 45 cubic feet 1 3 cubic meters of air per minute So if you put one of each in a rack you would need 90 cubic feet 2 5 cubic meters of air flow through the rack per minute under worst case condi tions 45 cubic feet 45 cubic feet 90 cubic feet Another way to increase cooling is to use air condition ing It is rarely a necessity because internal fans and rack mounted blowers almost always provide enough air flow for the most extreme conditions Still air condi tioning helps reduce the ambient temperature of the air flowing through the rack If you plan to use air condi tioning refer to Section 7 for information on calculating the hourly thermal dissipation of your system 3 3 Wiring Figures 3 5 through 3 7 show common ways to set up a Studio Reference amplifier Input and output connec tors are located on the back panel Be careful when CHANNEL 2 LOUDSPEAKER CHANNEL 1 LOUDSPEAKER 5 d 5 5 STUDIO REFERENCE E 21 bi AMPLIFIER STEREO
76. t devices Phone jacks are pro vided on the back panel while the factory installed P I P FX provides female XLR input connectors see Figure 2 2 Optional P I P modules like the P I P BB and the P I P FPX can provide barrier block and phono RCA connectors Various P P s are also avail able which provide a wide range of input signal pro cessing features see Section 8 Correct input wiring depends on two factors 1 whether the input signal is balanced or unbal anced and 2 whether the signal floats or has a ground reference Figures 3 8 and 3 9 show the recom mended connection techniques for each combination of source signal characteristics Shield connected Floating Source to apang terminal BESE Output naal l 2 wire line cord d or battery power 7 Twin lead shielded cable INPUT Grounded Shield is not source connected at this end th Output 3 wire grounded line cord or other ground connection INPUT Floating Shield connected to both source negative and ground ___inputterminals Output A 2 wire line cord or battery power Los INPUT Grounded Input ground source terminal not used Hh Output Single conductor coax or twisted pair NN Se is See EUN EN 3 wire grounded line cord or other ground connection Fig 3 8 Unbalanced Input Wiring Page 14 Studio Reference I amp If Professional Stu
77. t is important that you have your copy of the bill of sale as your proof of purchase 9 2 1 Service at a North American Service Center This method usually saves the most time and effort Simply present your bill of sale along with the defective unit to an authorized service center to obtain service They will handle the necessary paperwork and repair Remember to transport the unit in the original factory pack A list of authorized service centers in your area can be obtained from our Technical Support Group Studio Reference I 8 IM Professional Studio Amplifiers 9 2 2 Factory Service To obtain factory service fill out the service information page that follows and send it along with your proof of purchase and the defective unit to the Crown factory For warranty service we will pay for ground shipping both ways in the United States after receiving copies of the shipping receipts Shipments should be sent UPS ground If the unit is under warranty you may send it C O D for the cost of freight via UPS ground The fac tory will return it via UPS ground Please contact us if other arrangements are required Always use the original factory pack to transport the unit Factory Service Shipping Instructions 1 When sending a Crown product to the factory for service be sure to fill out the service information form that follows and enclose it inside your unit s shipping pack Do not send the service information form separately
78. ts compressor is driven by the amplifier s built in OC error detection circuitry Unlike typical signal driven com Studio Reference I amp Professional Studio Amplifiers pressors it only compresses the signal to prevent over load It can deliver up to 13 dB of additional headroom without being noticeable ISO cu z input h WARNING ar THIS P I P PROVIDES FULL ISOLATION FOR IS0 MODIFIED AMPLIFIERS ONLY DO NOT CONNECT THE OUTPUT GROUND m CH 1 INPUT h TO THE INPUT COMMON OR CHASSIS GROUND REFER TO P I P ISO OWNER S 150 Programmable MANUAL FOR FURTHER INFORMATION Input Processor P LP P I P ISO is designed especially for 25 to 140 volt dis tributed systems where UL listed isolation is required Installation requires minor amplifier modifications With the P I P ISO installed the amplifier outputs are safely isolated from the input terminals and the chassis CH 1 INPUT ATTENUATION ao ATN CH 2 INPUT h ATTENUATION 1 y Programmable Input Processor P LP P I P ATN includes all P I P FTE features plus a 32 step precision attenuator for each channel gt Programmable OUTPUTS INPUTS Input Processor P P P I P XOV is a versatile 18 dB octave mono crossover filter with biamping and triamping capabilities P I P FMX facilitates daisy chaining balanced ampli fier inputs Female to male three pin XLR connectors are used to p
79. uld still take the following pre cautions for optimum performance and safety 1 Improper wiring for the Stereo Bridge Mono or Parallel Mono modes can result in serious operat ing difficulties see Sections 3 3 1 through 3 3 3 2 When driving an inductive load like an electrostatic loudspeaker use a high pass filter or protective network to prevent premature activation of the amplifier s protection circuitry see Section 3 3 4 3 WARNING Do not change the position of the ste reo mono switch unless the amplifier is first turned off 4 CAUTION In Parallel Mono mode a jumper must be installed between the channel 1 and 2 red 4 binding post outputs Be sure to remove this jumper for Stereo or Bridge Mono modes otherwise high distortion and excessive heating will occur Check the stereo mono switch on the back panel for proper position 5 Turn off the amplifier and unplug it from the AC mains before removing the amplifiers P P mod ule or dust filter 6 Use care when making connections selecting sig nal sources and controlling the output level The load you save may be your own 7 Do not short the ground lead of an output cable to the input signal ground This will form a ground loop and may cause oscillations 8 Operate the amplifier from AC mains of not more than 10926 above or below the selected line voltage and only at the rated line frequencies 9 Never connect the output to a power
80. used 5 Connectors having any tendency to short should never be used Page 16 Studio Reference I 8 IM Professional Studio Amplifiers the damping factor decreases as the cable resistance increases This is very important because the ampli fiers excellent damping factor can be easily negated by using insufficient cable Use the nomograph in Figure 3 14 and the procedure that follows to find the recommended wire gauge AWG or American Wire Gauge for your system 0002 Rs SOURCE RESISTANCE ohms RL Rs 002 DAMPING FACTOR 20 000 004 10 000 8000 COPPER sop WIRE AWG 2 000 5 AL 1 000 1 LOAD L RESISTANCE TF 1 ohms 500 45 ohms 1000 ft 2 COND 1000 CABLE F 500 F feet Example Shown Rp 8 ohms Rg 0 016 ohms or D F 500 Cable Length 10 ft answer 8 wire Fig 3 14 Wire Size Nomograph Studio Reference I 8 IM Professional Studio Amplifiers 1 For loads connected in parallel use the equation that follows to calculate each channel s total load resistance Substitute the rated impedance of the connected loud speakers for the Zs in the equation When finished mark your answer on the nomograph s Load Resistance line Total Load Resistance in Ohms 112 112 tiza 2 Select an acceptable damping factor and mark it on the Damping Factor line Your amplifier can provide an pheno
81. vel controls has 31 detents for accurately repeatable settings In Bridge Mono and Parallel Mono modes the channel 2 level control should be turned down The meter switches are located behind the front panel They make it possible to switch between the dy namic range and signal level display modes for the meters or you can turn the meters off From the factory the meters automatically display dynamic range which is computed as the ratio of peak to average out put power To change these switches you will need to remove part of the front panel A phillips screwdriver will be needed and it will help to remove the amplifier if itis mounted in a rack Follow these steps 1 Make sure the amplifier is turned off and its power cord is disconnected from the AC mains source 2 Remove the two screws that hold each end cap in place and remove both end caps see Figure 3 2 3 Remove the six screws that hold each handle in place and remove each handle see Figure 4 3 4 Remove the dust filter by gently pulling it away from the front panel 5 Remove the two screws that secure the lower half of the front panel and remove the lower front panel 6 Locate the meter switches as shown in Figure 4 4 Set the switches as desired The left switch is used to turn the meters on and off and the right switch is used to change display modes 7 Reassemble the front panel handles and end caps in reverse order of disassembly 8 Install the
82. ven watts Cycle sen end X3415 Duty cycle of infrequent paging is 196 btu hr Amplifier Efficiency 65 Studio Reference LOAD 8 Ohm Stereo 16 Ohm Bridge Mono 4 Ohm Parallel Mono AC Mains Power Current Draw Amps Thermal Dissipation 4 Ohm Stereo 8 Ohm Bridge Mono 2 Ohm Parallel Mono AC Mains Current Draw Amps Power Thermal Dissipation Draw Watts 100 120 V 220 240 V btu hr kcal hr Draw Watts 100 120 V 220 240 V btu hr kcal hr 1325 15 9 7 2 1 780 450 1 925 23 1 10 5 2 500 630 1075 12 9 5 9 1 485 375 1 555 18 7 8 5 2 060 520 830 10 0 4 5 1 190 300 1 190 14 8 6 5 1 620 585 7 0 3 2 900 230 825 9 9 4 5 1 185 300 340 4 1 1 8 605 155 460 5 5 2 5 745 190 Fig 7 1 Studio Reference Power Draw Current Draw and Thermal Dissipation at Various Duty Cycles Page 36 Studio Reference I amp IM Professional Studio Amplifiers crown Studio Reference LOAD 8 Ohm Stereo 16 Ohm Bridge Mono 4 Ohm Parallel Mono 4 Ohm Stereo 8 Ohm Bridge Mono 2 Ohm Parallel Mono AC Mains Current Draw Amps Thermal Dissipation AC Mains Current Draw Amps Thermal Dissipation Power Power Draw Draw Watts 100 120 V 220 240 V btu hr kcal hr Watts 100 120 V 220 240 V btu hr kcal hr Fig 7 2 Studio Reference Power Draw Current D
83. w era of powerful ultraquiet amplifiers capable of faithfully reproducing the most demanding signals that state of the art 20 bit digital recording systems can offer This kind of sonic integrity does not happen accidentally It demands the leader ship and technical excellence for which Crown has long been known With the best transfer function in the industry ultra high dynamic range and extraordinary damping factor your Studio Heference amplifier comes closer to the ideal straight wire with gain than any other amplifier As you listen it will become apparent the amplifier s low frequency transient response is the standard by which all others must be judged We have taken great care at every step in the creation of your amplifier from the selection of its components to the routing of each wire It is our goal to provide you with total satisfaction This is one reason why we have spent considerable effort in providing you with the most complete Owner s Manual in the business Please read it carefully especially the instructions warnings and cautions It will help you successfully install and use your new amplifier Be sure to read Sections 3 3 2 and 3 3 3 if you plan to use one of the amplifier s two mono modes Please send in your warranty registration card today and save your bill of sale because it is your official proof of purchase We hope you enjoy your new ampli fier and thank you for choosing Crown 1 1 Features
84. y low input signal levels See Section 4 2 E Enable Indicator This indicator lights when the amplifier has been en abled or turned on and AC power is available F Enable Switch This push button is used to turn the amplifier on and off When turned on the output is muted for about four sec onds to protect your system from start up transients This is why a power sequencer is rarely needed for mul tiple units The turn on delay can be changed Contact Crown s Technical Support Group for details G Dust Filter The dust filter removes large particles from the air drawn in by the cooling fan In most cases the fan will not run so the filter will remain clean If the filter becomes dirty it can be removed for easy cleaning see Section 4 5 H Dynamic Range Level Meters A five segment output meter is provided for each chan nel The meters are factory set to show dynamic range of the signals in dB which is computed as the ratio of peak to average output power Also the meter can op tionally be set to show output levels see Section 4 4 T Meter Switches Two switches behind the front panel can be used to customize the output meters H By default the meters display dynamic range To make the meters display sig nal levels or to turn them off see Section 4 4 Studio Reference I amp Hf Professional Studio Amplifiers croun Fig 2 2 Hear Facilities Reset Switch This back panel switch can be u

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