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PROFESSIONAL STUDlO AMPLIFIERS
Studio Referenc
dio Referenee
Some models may be exported under the name Asrr@rou@
O "99 8y Crown Ir~ternatit:,nal, P.O. Box t COO, Elkhart. lndizn~i b fnc., 46575-?OQO U.S.A. Telephone: 219-2448000.Sfudio Refere?-9c:cawplifiers are produced by Crawn fnterrsaticsnal, Inc, xr'radernark Notice: Skrdio Reference'*and Gronnd~d &!.idge7"are tradcrnarks and Amcnm:'@ &IrcswsT 10C? ODEP IQ S,ysl'cm.e" and &"i.PF are registered trademarks trf Crcwn BntsrnationaY, Irx. Blher trademarks are the properv of their
respecliveowrwrs.
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The information furnished in this manual does not Include all of the de"iaifs s design, production, or variations of f the equipment. Nor does it cover every possible 8itua"ii~n which may ariss during installation, operation sr maintenance. if you need special assistance beyond the scope of this manuas, please eontact the Crown Technical Suppart Group,
Mai/: P.0. BQX4008 Elkhart lN 465?5-1000 Sbippin-ag: Pit. 2 S,W,, 1718 W, Mishawaka Rd., Elkhark E 4 5 7 N 61
Phone: $800) 342-6939/(2 ) 19 294-8206 FAX: $2" 9 1) 294-8361
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TO PREVEMT ELECTRlC SMOCK 80 NQT REMOVE TOP OR B Q n D M COMERS. NQ USER SERVICWBLE . PARTS INSIDE, REFER SERVOCtNC TO QUALIFIED SERVICE PERSOMNEL* DISCONNECT POWER CORD BEFORE REMOVING R R ENPUT MODULE TO ACCESS m GAIN SWITCH,
A PR~VENIRLE CHOG ~LECTRIOUEN'ENLEVU PA8 LES CQUVERTURES, RlEM DES PARTlES UTlLES A L"INT~RIEUR, D~BRANCHER BORNE u AVANT DWUVRIR U MODULE EN ARRI~RE.
f 0 REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT EXPOSE THlS EQUIPMENT TO RAIN OR MOISTURE!
Rev. Q
12-98
Initial Printing
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Studio Reference Service Manu3l
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1 Bntroductisn ................................................................................................... 3-1 1-1 1.1 The Stndis Referents ........................................................................ 1.2 Scope ................................................................................................ 1-1 1.3Warranty ............................. ~ . ~ ~ ~ ~ ~ . . . ~ . ~ . . A ~ ~ ~ ~ ~ . . . . , 1-1 . . . . 2 Specifications ................................................................................................ -2-1 2."Berformance ...................................................................................... 1 2 . 2.2 Pswei ................................................................................................. 2-1 23 Cantrofs ............................................................................................. 2-2 2.4 f ndicators .......................................................................................... 2.2 ...................................................................................... 2.5l~putsautput 2-3 2.6 Output Signal ..................................................................................... 2-3 2 2 Protcctisn .......................................................................................... 23 . 2.8 Construction ...................................................................................... 2.3 3 Va1tags Conversion ........................................................................................ 3-1 4 Circuit Theory ................................................................................................. 4-4 4.1 Overview ........................................................................................... 4-1 4.2Features ............................................................................................. 4-2 4.3 Frant End Operation .......................................................................... 4-2 4.3.1 Balanced Gnin Stage (BGS) .....................................................4-2 4.3.2 Variable Gain Stage (VGS) ........................................................4-2 4.3.3 Error Amp ..................................................................................2 4. 4.4 Voltage Amplification ......................................................................... 4-2 4.4.1 Voltage Transfators .................................................................... 4.3 4.4.2 bast Voltage Amplifiers (LVAS).................................................. 4-3 4.5 Grounded Bridge Topology ...............................................................4-4 4.5. Wigh Side (HS) ......................................................................... -4-4 4.5.2 Side (LS) Law ............................................................................4.4 4.6 Output Device Emulation Prccalectian (OBEP) ....................................4-5 4.7 Ganliol Circuitry ................................................................................4-6 4.7.1 DC$LFProtect ............................................................................ 4-6 4.7.2 fault Circuit ............................................................................... 4-6 4.7.3 Turn On Belay ........................................................................... 4-6 4.7.4 Fan Corjtrol ................................................................................ 4-6 4.8 Power Supply .................................................................................... 4-6 4.8.AC kine Fiiter ............................................................................ 1 4-6 423.2 Soft Start ................................................................................... 4-6 4.8.Over Voltage Protection ............................................................ 3 4-7 4.9Display Circuitry .............................................................................. "4-7 4.9.1 1QC ............................................................................................ 4-7 4"9+2 ODEP ........................................................................................ 4.7 ........................................................................ 47 4 3 3 Signal Indicafis~s .
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5 Electrical Checkout and Adjustment Procedures ,,,....................................... 5-1 5 1 General Informatiow ........................................................................... 5-1 5 2 Standard Initiat Conditions ................................................................ 5-1 53 DC Offset .......................................................................................... 5-1 5.4 Output Bias Adjustmen$.................................................................... 5-1 5 5 OBEP Voltage Adjustment ................................................................. 5-1 5.6 AC Pawer Draw ................................................................................. 5-1 5.7 High tine Gutsue ................................................................................ 5-1 5-8 Common Mode Wejects'sn ..................................................................5-1 5.9 Voltage Gain ...................................................................................... 5-2 533 Level Controls ................................................................................. 5-2 5.1 1 Current bimi"r .. ............................................................................... 5-2 5 1 2 Slew Rate and *a OK Square Wave .................................................... 5-2 5.f 3 Crosstalk ..........*<."........................................................................... 5-3 5.1-4 Output Power ................................................................................... 5-9 5.1 Reactive Loads ................................................................................ 5 5-3 5.16 ODEP Limiting .................................................................................5-4 5% Mute and Turn-On Delay ..................................................................5-4 17 5. Law Frequency Protection ............................................................... 18 5-4 5. 19 Signal to Noise Ratia ....................................................................... 4 55 5.20 Intermadulation Diskoflion ............................................................... 5-5 5.21 LED Functions ................................................................................. 5-5 5.22 Display Set-Up ................................................................................ 5-5 5.23 Turn-On Transients ........................................................................... 5-5 5.24 Turn-OM Transiep-rts..........................................................................5-5 525 Past Testing .....................................................................................5-5 6 Schematics ....................................................................................................6-1 7 Parts Information ............................................................................................ 7-1 7. 1 General lnfarmation ........................................................................... 7-1 7.2 Standard and Special Parts ............................................................... 7-1 7.3 Ordering Parts ................................................................................... 7-1 ........................................................ 7.4 Shipment .................... .,..... 7-1 7.5 Terms ................................................................................................. 7-7 .. , 7.6 Illustrated Parts List ........................ , , , . ................................7-1 Figure 7.1 Front Panel Exploded View ................... , .........................7-2 . . Figure 7.2 Top Main Assembly Exploded View ...................................... 7-4 Figure 7.3 Bottom Main Assembly Exploded View ................................ 7-6 Figure 7.4 Back Pans[ Assembly Exploded View ................................ 7-8 , Fi%jure7.5 Output Assembly Exploded View ....................................... 3-1 61 Figt,ire 7% Capacitor Assembly Exploded View ................................... 7-12? Figure 7.7 PIP Cage Assembly Exploded View ................................... 7-15
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Stvd8"~ Reference Service Manuai
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8 Module information ........................................................................................ 8-4 8.1 General information ........................................................................... 8-4 8.2 Studia Reference 1 Module lnfsrmatisn ............................................. 8-1 8.3 Studio Reference If Module Infsrmatisn ............................................8-1 8-4 Q.4397 1-6 Main Module ......................... .., . ..................................$3-2 . 8 5 Q43369-0 Outp&r"lodeelie .................................................................. 8-8 8.6 Q43183A3 Control Module .............................................................. 8-11
8.7 Q43.450-8 Control Module ...............................................................8-14 8.8 843584-2 Control Module ............................................................... 8-17 8.9 4 0 8-3 Display Modu8e ...............................................................8-20 a31 8.1Q 64331 1-2 Main Module ................................................................. 8-23 8.11 Q43388-0 Main Module ................... .,.. . .. , .............8-28 . ., . , 8. 2 Q43389-8 Butput Module ..............................................................8-33 t 8.13 a43312-0 Display Module ............................................................. 8-36
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Figure 2.1 Studio Wefsrence Dimensions ......................................................... 2-3 Figuss 3.1 Specific Voltage Wiring ................................................................... 3-1 Figure 3 2 Circuit Breaker Selection ...................,... ...................................... - 1 31 Figure 4 .t Simplified Studio Refereilea Biock Diagram ...................................4-1 Figure 4.2 Simplified Ampiitier Front End and Voltage Ampiifiication Stages .. 4-3 Figure 4 3 SimpfifiedGrounded Bridge ...................., .... .............................. 4-5 Figure 5.1 Differentiatar Circuit ........................................................................ 5-2 figure 5-2 Differentiated Square Wave .............................. ..,,,,..*+.+'......... 5-2 Figure 5 3 10 kHz Square Wave ................... .. ................................................. 5-2 Figure 5.4 inductive Load CoId ........................................................................ 5-3 Figure 5.5 5~nd~etive Warm ...................................................................... Load 5-3 Figure 56 Tartup@Yest Waveform ..................................................................... 5-4 Figure 5-4 OBEP Limiting Waveform ..................................................................... 5-4 Figure 7. 1 Front Panel Parts ............................................................................. 7-2 Figure 4. Top Main Assembly Parts ................................................................7-4 2 Figure 7.3 Bottom Main Assembly Parts ....................... .................................. 7-6 ........................7-8 Figure 7.4 Back Panel Assembly Parts ..................... . ....... Figure 7 5 Output Assembly Par& ................... . , ........................................7-16 Figure 7 3 Capacitor Asssmbly Parts ............................................................F.12 Figure 7 2 PIP Cage Assembly Parts .............................................................7-14 Figure 8. 1 a43371-6Main Msdule Map ..........................................................8-7 Figure 8.2 Q43363-8 Output Module Map ..................................................... 8-18 Figure 8 3 Q43383A3 Control Maduis Map .................................................... 2 8-13 Figure 8.4 Q 4 4 8 8 8 3 5 - Control Madula Map .....................................................8-16 Figuse 8 5 Q4J5Q4-2 2 Control Module Map ..................................................... 8-19 Figuw 8. 643818-3 Bispray Module Map ..................................................... 8-22 6 Figure 8.7 a 3 6 1-2 Main Module Mag ...................... .............................. 8-27 43 figure 8.8 843388-0 Main Module Map ........................................................8-32 Figure 8 3 043389-8 Output Modube Map ..................................................... 8-35 Figurs 8 1 Q43312-0 Display Msduls Map .................................................. '6 8-38
t .I Ths Studia Referenee
The Studio Reference amplifiers are the flagship s f Crown Internatfsna\.They oRsr the best in sound reproduction with a dynamic range capable of accurately reproducing 20-bit digital recardings. Super low harmonic and intermodulationdis$or$ion provides the best transfer function in the business. And the ultra-high damping factor af 20,000detivsrs superior foudspeaker motion control for a tight and clean low-end.
Schematics are included. Note that a Mexdu%e comis prised a$the circuit board with the component parts instal!@d. Crown does not sell blank (unpopulated)cis=. cuiQ boards.
CAUTIOH: TRs infermatien in this manual Is Intsndsd to b~ ossd by an exparlenc%dt@~hnlclaa h only
1.3 Warranty
Each Reference Manual contains basic pslieies as refated to %he customer. In addition, it should be staked This massr_eaI contains sewice information for the Grown that this ssrviee dacumentalisn is meant ts be used Studio Reference power amplifiers..It ia designed I ~ P snly by properly trained service personnel. Because most Crawn products carry a 3 Year Full Warranty (inbe used with the appilcable ReferenceManual' Howciud~ng round trip shipping within the United States), ever, some important information is duplicated in this aft warranty service should be referred to the Crown Servica Manual in case t h e Reference Manual is not Factory or Authorized Warran& Sewice Center. See the readily availabls. applicabls Owner's Manual for warranty details,To find the iocation Q nEarsst Authorired Sarvice Center, the I This Service Manual includes severaB sections,These sectiians include Sp~cifications, Vottag~ Conversion, or to obtain instructions fcar receiving Crown Factory Circuit Thssry? EEfectrieal C h e ~ k o u tParts Information, Service, piease contact tho Crown Technical Support , Module Information, aod Exploded View Drawings, Group (within North Amerrca) or your Crown/Amcrg;bn Importgr (outside North America),
1.2 Scape
Plant 2 S.W, 1718 W. Mishawaka Bd, Elkhaa, IN USA 4651'7
Phone: (219) 294-8200 Tall Free: (8QO) M2-6939 F M : (219) 294-8301 Web: .er~wnaudis~com
Introduction t -7
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introduction 4 -2
Studio Referenee Service ,Msnual
The following specifications Mode, with an 8Ohm load, a 26dB, banless stherwise specified.
on Bode Wajsctlon [CMR):Better than 100 dB beted full bandwidth power from 20 Hz to 480 Hz, rising tinearly I better than 79 dB at 20 kb4z, s
Voltage G ~ i n :(With Isvel controls set far maximum ocnt: put,) At the 2 d B garn setting, 2 Q : h 3 %or 26 dB 6 ~ 0 ~dB, 25 Studio m , n , & z ; e L At 0.775volt sensitivity? 'I 1 k 12% or 40 dB 1 dB; at 1.4 volt 63: sensitfvity,57: k 12% or 35 dB k 1 dB. 1 S d - ..-. to ui At 0.775 volt sen%itiviby, 6 9 : k j2% ar 37 dB 41 dB; at "84 volt sensitivity, o 38.1 ~ 1 2 % o r 3 2 d BdB. ~1
Low-.DJ&o~P@@ Psaar: Refers to maximum avert kHz age power in watts at 1 kHzwith 0.02% THO and noise..
S t a ~ d ~ r B Power: Refers t maximum avsrage 1 kHz s pswer in watts at I kHz with 8.1% TkJD and noise,
Full B ~ n d ~ i dPawer; Refers to maximum average th pawer in watts from 2 Hm to 2 kHz with 0.1% THB 0 6 and noise.
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2,l PeHormsnee
Ftgquency Response:: ~8,MdB 20 Hs to 20 kHz at from
1 watt.
2,2 pa we^
P s ~ eBandwidth: (At standard 1 kHz power.) r &,df-rence6: -^B dB from 5 Mz to 27.5 kHz and - dB from 3 Hz ta 32.8 kHz. 3 -1 dB from 5 Hz fa 28.6 kHz and --3d B from 2.3 Hz to 34.4 kHz,
Phase R~$pon%@: to -75 degrees from 20 Hz ta 2 +5 6
kHz at 3 w ~ t t ~
8ignai-to-noise: (A-weighted)
reater than 120 d B belaw
rcater than 13 7 dB below
full bandwidth powerh
Tat@! Harmonic Dldsalon (TWO): Less than 0,02% a 4 rated low-distortion I kHz pswer. Less than 0.1% af rated full bandwidth power,
tsw-Di%tofllsn f kHz Butput Power: S udio Rcf@rea& f .... $t~?rea Made with both cchannsbs driven. 1,160 watts per channel into 4 ohms, 7 8watts per channel into 8 ohms. 6
B~idge-Mono mode: 2,228 watts Into 8 ohms, 1,580 watts into 16 ohms
P8~3I/e/-Msn0 mode: 2,37 5 watts into 2 ohms, 1,565watts into 4 ohms.
lntsrmoduEIaZlon Qiatagian {IMDf: (60Ha & 7 kklz 4: 2)
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Studio R ~ f ~ Less than 0,005%from full r w bandwidth power to 78 watts rising linearly to 8.025% at 78milfl~atks~ Studio Re f Less than 0.005% from ;Bull bandwidth power ta 36 watts rising lineariy $a 0.025% at 36 mtliiwatts,
Damping Factar: Greater than 20,000 from "B BHZ to 280 Hz, and greater than 2,568 1 kHz. at
Crosstalk: (At rated full bandwidth power,) S b ~ dReferi~ Batter than 1 6 dB from 0 25 Hz ta 100 Hz, falling linearly to better than 4 70 dB at 20 kHz, Betdef khan 180 dB from 20 M E to f 66 Hz, falling tinearly to better than 65 dB at 20 kHz,
m,,B@Stereo Mode with both chag.gne!sdriven: 555 watts per channel into 4 ohms, 355watts per chanilel into 8 ohms.
Bridge-Mono mods: "i110 watts into 8 ohms. 715 watts into 16 ohms.
Parab/e/*!donsn~ade:
1,115watts into 2 alms. 730watts inta 4 ohms,
Stereo mode wid)~ both ~haanneIs driven: 1,190watts per channel into 4 ohms. 800 watts per chaunef iota 8 ohms,
Bridge-Mono mode: 2,375 watts inis 8 ohms. 1,595 watts into 16 ohms.
Enable: A front panel push button used to turn the amplifier on and off,
Level: A front panel rotary potentiometer far each ehannel with 3 1 dstents, used $0C B ~ ~ F O I the output level.
Stsreomono: A three-pasitiaw back panel switch used to select either Stereo, Bridge-Mano or Parallel-Msns
SsnsitivlQ: A three-position switch inside the P,l,I,p cornpartment used ta select the input sensitivity for both ek?annefs: 6,795 i 1.4 volts for standard 'IkHz pg;aw~r, a
or 26 dB voltage gain,
Par~jIef-Mono mode:
2,350 watts into 2 ohms, 1,588watts into 4 ohms.
St~d8"o RefefcnceH: S!W@Q mode wifh both cchanne/s drjven: 565 waus pea channel into 4 ohms. 360 watts per channel into 8 ohms.
Mater OnfBff: A tws-position switch behind the front pane! used to turn the front panel meters on or off,
Bridge-Mono m ~ d ~ r 3 ,f 45 waEs into 8 ohms, 720wakk into 16 ohms
Par8$/@/-Mono mode:
7,135watts into 2 ohms. "715waE%into 4 ohms,
Meter Display Mode: A twa-position switch behind the frsnt panel used to set the display mudc tor t h s front panel meters. Display modes include dynamic range af the output signal in dB or output levels in dB.
Ground Lift: A two-position back panel switch used to isslate the irrput phone jack and AC {chassis) grounds.
Full Bawdwidth Butput Pewer: (20 Hr lo 28 kHz)
E@r@o made wjtfi both -lh~aanne/s drivepa: 1,075 watts per chanaal into 4 ohms. 768watts per chaalnel ir3Po 8 ohms.
BrBdge-M~f?~ 2,150 watts into 8 ohms+ " , 3watts into f 6ohms. 355
$&2dio Ref-K St~f-sa mode wifk bath chhanng!~ db^ven: 495 watts per channel into 4 ohms. 340 watts per chaanel into 8 ohms.
Reset: A t w o - p ~ ~ l t i o n panel switch used fa roset back t h e AC mains circuit b~eaker*
2,4lndicatars
Enable: This indicator shows the o n / M status of the unit's How-voltage power supply
Signal::Each channel has a signal inclicatar that flashes
to show audio output.
Brid~e-Mgbf?~ mode: 1,020watts into 8 ohms. 698watts into 16 o h m s .
i@C: Each channel has an 18C indicator %hat flashes if the output waveform differs from the input wavsform by 0.85% or more. The LED$ act as sensitive distsrtion indicators to provide p o f of di~f~rtian-free ro performance, In Paralfel-Mono mode the channel 2 / @ 0 Ilght stays an.
Load Impedsn~e: Safe with all types of loads, Raked far 4 ts 8 ohms in stereo mode, 8 ts 16 ohms in BridgeMona made, and 2 to 4. ohms in ParalteI-Mon~ O ~ G , M
Required AC Mains: 5 or 60 Hz; 1 6 120, 200, 220or 6 0, 240 VA6 (k 10%)< Both units draw 90watts or less at
0DEP:Each channel has an ODEPindieator that shows the channel's resewe energy status, Normally, the LEDs are brigfatly tit to show that reserva energy is available. In the rare event that a channel has no reserve, its indicator wisi dim in proportion to BDEPlim-
idle.
Dynamic Ranga/Lsuel Meter: Each Channel has a fiveInput: Input overload prstectisn is furnished at the segment meter that displays either the dynamic range amplifier input to limit current. of the output sigrrai in dB sr the output love! in dB, (From the factory, the amplifier is set to display dyTurn On: The four second ~ C ~ T M - deilay prevents dam Q~ namic range.) A s dynamic range meters, they show gerous turn-on transier~ts, %he ratio sf peak to average power of tach channel, As output level meters they show how high the ~ ~ ~ l p u t Constrvctlon 2,8 levels a r e relative to standard 1 kHz powerq Steel chassis with durable b8ack finish, aluminum front panel with super-glass Imronfinish, l e x a ~ , averiay?and 2.5 llnputlOutput a specially designed flaw-through ventilation system input Csnneetor: Two balanced '!,is-inch jacks an the from front to side panels. back panel and two balanced three-pin XLR connectors on the factory-installed P..B,?-FX, CoeiJng: Convection cooling with assistance from the computerized, on-demand proportional cooling fan. lnput impsdanee: Nominally 10 K ohms, balanced Pdornina!ly 5 K ohms, unbaianced. Dimen$ions: Standard 19 inch (48.3 em) rack mount width fElA RS-316-B),9 inch (17.8 cm)height, 16 inch I ~ p uSan%itiuiQ:Settings include 0,775 t volts sr 1A volts (40'6 CM) depth behind mountingsurface and 2.75 inch for standard 1 kHz pswea: or 26 dB voleage gain. (7 em) prstrusion in front sf mounting surface (sea Fig. 2.1 belaw), Output Canaeetam: Two sets of color-coded 5-way binding posts far each cha~3rrel(for connecting barlana plugs, spads lugs si bare wire),
Qutput Impsdaase::Less than 10 miBliahms in sarisa with 2,s micr~henries,
DC Output 8@ssZ;(Shorted input) 3 2 millivslts.
2.6Output Signal
Starsa: Unbalanced, twa-channel.
Brldgs-Mona: Balanced, singla-channel. Channel f controis are active; channel 2 should be turned down.
Parallai-Mono: Unbalanced, single-channel.Channel "icontmls are active; channel 2 is bypassed.
which could stress the output circuitry?the QDEPcircuit limits the output current level until safe operating conditions exist.
2,7 Protection ODEP: ff unreasonable operating conditions $~~g;;urApprsxlmata WaiigM: Center of gravity is about 6 inches (15.2 behind the front mounting surface. cm)
Trensformer: Transformer overheating will result in a temporary shut-down due ta a ttmerrnal ~wifchin the
1
60 pounds, 11 ounces unds, 3 ounces (332k g )
shipping weight.
transformer primaryRF Burnout: Controlled slew-ratevoltage amplifiers pro-
56 pounds, 2 ounces (25.5 net; 69 pounds, " 0ouncss (31"6kg) kg) 1
shipping weight.
tect the unit agairlst RF burnouts,
Specifications 2-3
Studio Reference Service ManuaI
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Studio Reference Service Manual
age Convers -."-
The Studis Reference Ampfifiers can be wired for 100 VAC? I20 VAG, 200 VAC, 220 VAC or 240 VAC operation, This is made passible by the use of a multitap transformer for the high energy power supplies. Perform the fallowing pracedure and refer %s Figures 3.3 and 3.2 ta convert the operating voltage. YOUmay have to order t h e approprate circuit breaker using the part number listed in Figure 3.2.
corner of module). 3, Cut and remsve the wire ties to access the jumpers and wires, 4. Refer to Figure 3,1 and make the appropriate charrges for the desired operating voltage. 5. lnstaBI wire ties to dress the wires above the conright hand
CAUPfO#: B~eausa thare 1% a risk of slsctr!~sheek, sniy on gxperisne~d t~ehnician ahould aggmpfk ts altgr the line
valtage contlguratiian,
1. Remove tha tap cover of the Studio Referenee amplifier (held on by 8 screws). 2, With the front panel toward you, locate tka controt module {frontcenter) and the tab connectors (upper
nections. 6, Note the switch on the ief2 hand side of the module and change, if necessary, for the operating line frequency. 7 , Refer " Figure 3 2 and change the Circuit Breaker if I necessary+ 8. On the rear 0 $he unit, change ?$"re cord tag to 5 line read the correct valtage. This is on the lower right hand side of the rear panel, just above t h e serial tag. 9, ReassembHe the unit.
VOCrAGE
JUMPER
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WPt 6
Figure 3.1 Specific Vo1tage Wifing
Ct RCUfT BREAKER SELECTiON
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AMP. Cl 0193-8
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Voltage Conversion 3-2
Studio Reference Service Manual
INVERTING
BRIDGE
LOW SIDE
OUTPUT
BWUNCE
PNP STAGE
Circuit Theory 4-1
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plastic case style.This alIo\~s a significantlyhigher for thermal margin for the given voltage and current ratto ings. Ail devices used are tested and grad~d ensure maximum reliability,Another electronic technique $puts the BGS, the signal goes to the f used is negative feedback. Almost atl power amplifigain is determined by the position of the ers utilize n~gativa;. feedback8 control gain and pro0 itch, and lev@/ detc~mined the level is by vide stabifity$ Crown uses multiple nested feedbut s an inverting stage with the input being back imps far maximum stability and greatly impag>k/ed mp stage. Because gain after this stage damping. Studio Reference ampiifiers have damping B (factors 2Q), f greater amplifier sensiin @XC$S$ af 20,000 in the bass frequencyrange. This s d $y csntrosling the ratio of f~edback feedback,along with our compensation and u t " l 3 - l ~ ~ nee, The Sensitivity Switch sets the indistortion output tapol~gy~ make Grown Studio Refput impedance to this stage and varies the gain such erence amplifier superior* that the overall amplifier gain is 26 dB, or is adjusted or 0.775V ar d.4V input to attain rated Fsatt~res specific to the Studio Reference include: A high power toroidal Esansfsrmsr;Computer controlad, varjable speed, whisper quiet fan; Built in AC power fiffes; Softstart circuit Z control inrush curroot; Fuji ova tpuX from the VGS is fed to the nonervodtage and internal fault protection, This amplithe Errof Amp op-amp stage through fier can operate in either Bridgge;! Parallel Mans mode, or capacitor $Ct 00)and input resistor as well as in Dual (stereo) made, A sensitivity switch output is led back via the negative a)lowsseiectian sf input voltage requiredfor rated &rutop re~istor 1 3 , ratlo of feed(W Q ) The put. Level cnr-llr~ls mounted on the front panel and are are of the rotary type, Front panel indicators let the tpuWof the amplifier at 26 dB, Biuser know the status of amplifier enable, QDEP9signal revent averdriving the Error Amp. presence (SP!), and distortion ( 0 )Alsa included on 9C, mp amplifies the difference bethe front panel is a five-segmet display Tr each chano ut signals, any differencein the riel which displays either dynamic range tn d B ar auttwo waveforms will produce a near open loop gain put level in dB, condition which, in turn, results in high peak auWpu&. ths Error Amp, called the Error For addiriauai details s~fer the specification section, to Signal (ES) drives the Voltage Translators, or ta the appficable WaFerence Manual,
k to interrupt around lw~=os the Ground via Lift Switch. The non-inverting (hot)si& of the balanced Studio Referenee amplifiers utilize numerous Crown input is fed to the non-hverting input of the; firs@ opinnovations, including gf@tuflded bridge and ODEP amp stage. The inver"ring (negative)side o the balf teehnofogies. Cooling t~chniques make use o what is f essentially air conditianer technology.Air flows bottom ancsd input is fed to the inverting input of the firswspamp stags. A potentiometer is provided far esmmon lo top, and front to side. Air ftsws a shafi distance rejection adjnmstment ( R 5 f2.Electricaiiysthe BGS ) across a wid@heatsink. This type of air flow pro.\rides mod@ is at unity gain, (From an audio perspe~tive, however, significantlybetter emling than the "wind $unnel'"techthis stage actually provides +6dB gain if a fully bainology used by many other manufacturers, Output stransistors are of the metal can type, rather than f h ~ anced signal is placsd on its iraput.) Tho BGS is a n n
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4.3 Front End Operation
The front end is comprised of three stages: Balanced
4.4Voltage Alnplifi~ation
The Voltage Translator stage separates the output of the Error Amp into balanced positive and negative drive vol"s~ge?s the Last bltage Amplifiers (LVAS)~ for translating the signal from ground referenced n15V to kV@c referenee, LVAS provide the rnak voltage amplification and drive the High Side output stages. Bemuse there is a slight lass of gain in the translator stage, the gain after the translatar is a factor of 25.2,
Gain Stage (BGS), Variable Gain Stage {VGS), and the Error Amp. Figure 4 2 shows a simplifieddiagram o the front end and voltage ampixfieation stages, f
4-3,f Balanced Gain Stage (80%) lnpk~t the amplifier is balanced, The shield from the ts 1/4" inputs may be isolated from chassis ground by
Cir~uit Theory 4-2
ence. Their outputs drive their respechive tVA,
muting transistors, The QQEP transistors steal drive as dictated by th@ BDEP circuitry or shunt the audio as dietated by thg fault circuit,
Circuit Theory 4-3
Figure 4.3 is a simplified exampfe of the grounded bridgs output topology. It consists of four quadrants of three deep DarDington (composite) emitter-follsw~r stages per channel: one NPN and one PNP an the High Side of the bridge (driving the Isad), and apse NPN and one PMP an the Low Side of the bridge (controlling the ground reference for %Re rails). The output stages are biased ta operate class AB+B far ultra low distortion in the signal zero-crossing region and high efficiency.
A diode suing pr~vents excessive charge build up within the high conduction output devices whew off, Flyback diodes shunt bask-EMF pulses from reactive loads to the power supply to protect output devices from dangerous reverse voltage levels. An output terminating circuit blocks W on output lines from enterF ing the amplifier through its output connectors,
4,5.% High Side [NS)
Thhe High Side (HS) af the bridge operates much like a conventional bipolar push-pull output configuration,As the input drive vsitage becomes more po%itive,the HS NPN conducts and delivers positive voltage to the 10ad, Eventually the NPN devices reach full conduction and +Vcc is acrsss the load, At this time the HS PNP is biased off. When the drive signal is negative going, "Be HS PNP canducts to deliver -Vcc to the load and the HS NPN stage is off.
~ The output of the +LVA drjvm the base of $ 8 . pradriver device. Sgsgethar, the predriver and driver farm the first two parts sf the three-deep Darlingtonand are biased class AB, They provide output drive through the bias resistorxbypassing the output devicas, at Bevels beIsw about 180mW, An RLC network between the predriver and driver provide phase shift csmpensation and limit driver base current $asafs Bevels. Output devices are biased class B, below s%sculotf. about Just At 1QOmW blr~tpat they switch on to eonduct high current to the load. Together with predriver and driver? outthe put device provides an averall cFass AB+B output,
4,5,2 L@w Side (L8) The tow Side (LS) operates quite differently. The power supply bridge rectifier is not ground referenced, nor is the secondary of the main transformer, in othsr wards, tha high vsltage power supply floats with respect ta ground, but ~ V c remain canstant with respect to each c other, This allows the pswer supply to deliver +Vcc and -Vcc from the same bridge rectifier and fiitsr as a total difference io potential, regardless of their voltages with respect ts ground. The LS uses inverted feedback from the HS output $0control the ground refer* ence for the rails (AVCC), Both L quadrants are arS ranged in a three-deep Darlington and are biased AB+B in the same manner as thc WS,
When the amplifisr output swings positive, the audio is fed to an sp-amp stage where it is inverted, This inverted signal is delivered direeIIy to the bases of the positive (NPN) and negative (PNP) predrrivers. The LS negative drive forces the L PMP devices on (NPN S off), As the PNP devices coaduct, VCB af the PNP Darlington drops. With LS dsviics emitters tied to ground, -Vcc is pulled toward ground reference. Since the pswer supply is not ground referenced (and the tatai vsltage from aVcc to -Vcc is constant) +VGC is forced higher above ground potential. This continues until, at the positive amplifier output peak, -Vcc -. OV and +VGC e q ~ a I the total power supply potential with s a positive pslarily' In the Reference 1, for example, %he power supply produces a totat af14488 from rail ts rail (k72VDC me?asur@d from ground with ns signal), therefore, the amplifier output can reach a positiva peak sf +"I 44v*
The negative half sf the HS is almsst identical to the positive half, except that the devices are PNP One difference is that the PNP bias resistor is slightly greater in value sa that PNP output devices run closer to the cutoM level under static (no signal) conditions, This is because PNP devices require greater drive current.
WS bias is rsgulated by Q18, the Bias Seavs, Q l S is a Vbe multipiier which maintair-rsapproximately 3,2V Vee under static conditions, The positive and negative halves of the W output are in parallel with this 3.2V S With a full base-emitter on voltage drop across predrivers and drivers, tha balance of voltage rasuits in approximately .3V drop across the bias resistors in the positive half, and about .5V acrsss T e bias resish {and ~ tor in the negative half, Q J bn$ ~ ~ n d ~ c l i o rthus bias)
Circuit Theory 4-4
Cosrversely, during a negative swing af the HS output
where HS PNP devices conduct, the op-amp would
output a positive voltage forcing hS NPN devices to canduct. This would result in +Vcc swinging tsward ground potential and -Vcc swinging further from groidnd patentraf. At tl-$6 negative amplifier sutpvt peak, SVCC =z OV and -Vcc equals the tstal power supply potential with a negative pofariWy. Using the same ex-
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k72VDC statically) is capable of produsing 288V
rent (negative amplifi~r output) and +Vcc are sensed,
An iocrease in positive output signal into a load will
measurable by normal means) and the time delay from
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4.7 C@~tr@l eireuitry
The Reference amplifiers have fault protect circuitry to guard against dangerous DC voltages and turn on/ off transients, At the heart sfthis ~ir~~ifry winthe dew comparator ~ 1 0 2?kg fan control girc~ij: , monitors the thermal conditions, via the OBEP eireuit, and regulates the fan speed accordingly,
4.7,1 DCBF Pr@t@@
The amplifier output sigf-ralis passed through a low pass filter (R184, C1 19, R186 *and C107)ts the windew comparator (UJQ21, if DC campsnent exceeds a predetermined level, the output o the camf parator (pins 1 and 2) goes law. The result is U302 pin 23 going to a high state which turns on the muting
nal. As the outpeat transistorlheatsink increases in temPeratu~e, ODEP voltage kvei will drop fmm the +joVBC f3ear ~ ~If ~ 1s a dropv one of C in both QDEP vsltages it will Cause the fan csntroi signal to change,The fan contra& signal starts out around -12.5VDC, 3rd after complete ODEP limiting, ends up at + 12,5VDC0Phis voltage is fed into the inverting input of the op-amp U1B, The initial output sf U1B is high $+24V), and as the fan control signal becomes more positive, this output will became low, thus turnThe ing the fan accordin~j~~output of U1I3 drives U4,an opts-triac, which in turn drives Q4, a triac in AG supply forf h e fan,
Ph@Gating Signadis fed into the nsn-inverting input of $heQP-amP Uj@+This gating signal is a p ~ ~ d uof t c U7 A, Q 3 , and the Fan Enable signal from the display madule., C12 and RE3 farm an RC timing circuit that, from the +15V supply, begins I charge, U1A rnonis tars the tine voltage wave farm and is a O i l crossing detector. Every lime the line waveform crosses OV, Q4 is turned s ? discharges C12, This causesa rampa and ing type waveform.The higher p~$i$ive portion of .&he ~pto-triac, aven when waveform is used to turn off %he the fan contrkal signat itself is a a value k turn sn the F s fan.Therefare,the fancantrod curr~nt a duty cycle, has
transistors and disables the high energy supply by opening the relay K2.
4,7,2 Fsuft Circuit The fau&circuitry i designed to mute s audio and disa$le the high energy supply in the event of an output fault. A fau/$is defined as any time in which t h e output semicsnductars, in both the negative and positive sections, draw excessive currents,
The [ow side of &ridgefaultdetection consists sf Q128, Q329 and Q130, ff both NPN and PNP output devices are conducting excessive cajirrents,tha output af U'T82 (pin 13) is forcegs$high, This disables the high energy supply and mutes the audio path,
The high side s bridge fault detection consists of f a126,Qf 2 and U101. This circuit compares the NPN 7 and BNP drive to the feedback signal, giving a representation of output devics current. If excessive curwnt occurs, the window cegmparatsr U1Q2is triggered through the opto isslatsr U101.
'The f%f? Enabje %nai cQm@s the display !"nodfrom u!@and holds the Gating Si~flaf when the amp& high fief is in standby<"I^'herefsfe the fan will not turn when the amplifier is in standby*
At the heart of the power supply is a muiti-tap torraidaH power transformer, There are two ungrounded, high energy, secondary windings, one for each channel, and there is one low voltaga winding for t h e 24V supplies, "f?er@ also a thermal eu% switch built into is off the transfarmer wtlich will disable the secondary windings in the event of the transformer overheating.
4.1.3 TBFR8 n Bs%ay During power up, the capacitor C'I 1 is charging, 8 which causes %he nan-inverting input {pin -4 0 of U 182 9 to be !OW and the output (pin 13)$0be high, With pin 13 high, the high energy taik are disabled by the r e lay K2,and the audio is mutsd by the muting transistors. A f t ~ r approximately 4 seconds, C1 " Qis fully I charged and pin 10 is pulled high, thus causing pin 13to go low and the amplifier to :,cams out o standbyf
4,7,4 Fn Centre! s The F8n ContrdSi~na$is t.akenfromthe positive ODE$ bias valfages. Both channel 1 and channel 2 ODEP voltages are eambined to create the fan c~rrtrsl sig-
4,8,1 AC tin@Filter
824 and 025 are ir-t the AC primary, They are wired such that they null out any DC compo9-ren"inthe AC pawereThis done because the tarriodiat transformer may develop a mechanical buzz if them is any DC shift in the AC waveform applied to the transfarmer
inrush current that is possible with the rmer, a SO%$ Circuit has been inStart
Circuit Theov 4-6
and power is applied diractty to the transformer.
4,9.3 Signal Indlcatlan incorporated on the display module are three modes
ef signal indication.
4,8.3 Over Voltage Proteetion U l El serves as a window comparator for the purpose of over line voltage cantro!, In the event that the line vslfags sxceeds 10%over the rated line voltage, the high energy power supplies are disabled, W %up7 plies the regulated + I SV to pin " of U1B and serves I as the window reference level. With pin 10 in csntrof of U1D, output: (pin 1 )has a logic law which is &he 3 applied across 033 and 014, This prevents csndue-
S B (Signal Presence Bndicnfiow) U1A and D3 serve to rectify the amplifier output signal. U1B takes this rectified signal and drives t h e LED, E3, which illuminates any timg there is signal pre~ent
at the autpkdt of the amplifier channel,
Dynamic Range
With t h e switch 51 in the Dynamic position, this rectified audio signal is placed on the invsrtin~ inputs of a sequence of window comparators.This signal is rectified but unfiltered, therefore it contains ah@ peak value of %he audio waveform, U3C, U3D, USA, U5B and U5B serve as the current sources for the five Dynamic Range LEDs. R29,R 3 t R33, W35, R37 and R39 provide a resistor dropping network for the inverting inputs " ah LED drivers, l te
tisn and allows Q1 to remain on, which thus allows K2 to remain ensrgired
Resistors W3, W4, R5 and R6 serve a$ a resistor dropping neWsrk from the unregulated +24V supply to ground, A s the line voltage incraas~s,h e unregulated t supply will increase, The voltage ievsD s the wiper of n R4 is applied to Pin 11 (non-inverting input). When the Hevel exceeds %he window level of pin -10, circuit the switches states, This allows D 3 and 014 to canduet, l
placing a logic high on t h e base 0% 1 % 0 This,iu turn, biases off Q 1 and de-energizes K2.
4.9 Display Circuitry
4.9.1 ilOC
U3A and U3B serve as a voltage comparator with R13, R15 and R'W 7s the r@sistor dropping newark. Pin '7' has a window level of +7V and pin 4 has a window of -7V U3A and U38 have a logic high which turns off and the 1 0 ~ El, when ths LEO Signal fro.cam the error amp appears, the 7V window is overcame and switches t h e state of U3A and U3B. Q1 is then biased on and the tOC LED, E l , iliuminates. The capacitor C27 makes sure the LED is lit long enough for the human eye to see it.
This same reclifisd signal is placed an the non-inverting i~lputs the filtering Function o C3 and the opvia f amp, C. filtered sigr~al of an RMS value, With U1 This is the nan-inverting inputs receiving the RMS value, and the inverting inputs receiving t h peak value, the aut~ pull of each LED comparator equals the dynamic ranga of tha signal,
a1
Output Leved With the switch, $1, in the Level positian, the peak signal is still placed on the inverting inputs af the cornparatsr drivers. A small DC level is piaced o all of the w non-inverting inputs, This DC level serves as a cali$rated reference far comparatofs. W78 calibrates the display balance between the two channels sf the amplifier"
4,9,2 60EP U1B on the display module is the curr@nt source far the OBEP LED E15, Under normas operating conditions pin 14 of Uf D is a negative vsitags. This allows B ts conduct and El5 to illuw~inate. s the ODEP Y A signal drops ts the point wkiiere OBfP limiting takes
Circuit Theory 4-7
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t8,9 28.0
Procedures
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9.91 9.86
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5,2 Standard initial Cowdltigns
Level controls fully clockwise. StereoBMano switch in Stereo. Sensitivity switch in 26 dB fixed gain pasition. It is assumed, each step, that E e conditions of the in h amplifier are per these initial conditions unless otherwise specified,
32.2 -9.63
9.80 9.44 9-69 9.63
5,3QC Offset
Spgc; 8 WBC, 2 rnV k lnltial Ce~dttOax~gr Controls per standard, mputs shorted Preeadurs: Msasure DC voltage at the sutput canncctors (rear panel). There is n adjustment for output offs set. If spec is not met, there is an afectricai rnaifunctian, Sligh8fyout of spec measurEment is usually due to U"iQiU204 0165: of tolerance,
-ODEP Proe8Bure: Measure pin 3 of 3500and, if newssary, adjust R121 to obtain V,, a s specified above. Measure pin 3 of J700 and, if necagsarx adjust R22t to obtain V ,, as s~ecifred ,, above, +OOEP ~rocgiite:e a s u r e 4 of 3500 and, if neces~ pin sary, adjust R132 to obtain V, as specified above. +, ,, Measure pin 4 of J700 and, if necessary, adjust R232
5,6BC Power Draw
Spbc:: 70 Wazrs nmaximkam quiescent. initial Csnditions: Controls per standard. Procedure: With no input s i ~ n aand BBQ16ad, measure l AC line wattage draw. if current draw is excessive, check.far high AC Iim voltage or high bias vsitaga.
5 4 Output Bias Adjustment .
Spec: 300 ta 320 rnVDC, ilnitiall Gandstiaa$::Contrais per standard, healsink ternperatare less than 4 ° 0C P~oeedurs:Measwe DC voltages or? the output module across R02, adjust R26 if B-eecessary,Measure DC voltages on t h e output module across R21, adjerst R23 if necessary.Repeat for second channel.
5.7 High Line Gutout
Spec: Unit goes into standby when the AC line voftage goes ^f 8% to to 12% aabw onominal,
5.5 ODEP Voltage Adjustment
Spat: Bias Per Chart, ~ 6 , 4 V DC. InltiaiP @oiaridition%: ContnaSs per standard, heatsink at room temperature 20 t 30°C (68 86°F)" Note: This o to adjustrnerr"rh8ufd nsrmaliy be performed wilhin 2 r~rintsts% turn an from ambient (esfd) cornditions, If 07 possible, measure healsink temperature; if not, msasure ambient room temperature. Use this infarmation
when referencing the $.a/lawing chart,
lnltial Gondltionsl: Controls par standard. Proeedgre: No load, no signal, Bring up AC line voltage with a variac 10%to 12% high. Far 120VAC units this is 132VAC is 334.4VAC. Unit should go into standby. Adjust R4 sn the control module if neees-
sary.
5.8 Common M o d e Reje~tion Spac: >70 dB at 1 kHz, initial Cendilions: Controls per standard, Prosgdure: No load, Inject a 0 dBil(.775VRMS), 1 kHz sine wav@into each channel, one channel at a time, wieh inverting and non-inverting inputs shorted togetkaer. Adjust R512 ( C h l ) and RE12 (Ch2) for less
than 4,9mVRMS (-44 dBu) at the amplifier output.
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Elcctrfcal Checkout 5-1
Gheckou
5.9 Voltage Gain
Spee 2666 Gg%n;Gain of 20,8 k3%. Spac 0.775V 5 e ~ % i t l v iREF I ."---Gain '508.65 ~: at &3%, REF ! i - ~ ~ ~ ~ ~ 68,28 E a%n. af ~ ~ ~ ~ 3 i ~ Spec 1.4V S~nsltivlQ: I ---Gain of 5521 &3%. REF REF t l ----Gainst 37 .SOa3%, Inibtia%l Eondlti@n%: Controls per standard. 26 dB Procsduf@:Inject a 0,775 VAC 1 kHz sine wave with the Sensitivity Switch in ths 2 dB position, Mea6 sure 15.5 f0.S VAC at the amplifier skstpu2. VAC 0,775V Prosedut~:: Inject a 0.775 VAC 1 kHz sins wave with the Sensitivity Switch in the 8.975V position*REF i measure 78 VAC, f2.3 VAC, at Z @ h amplifies output. REF I I measure 52.9 VAC, ;s;. "1.6 VACt at the amplifier
output.
Procedures
1.@V Bros@dure:lnject a 1,4 VAC 1 kHz sine wave with the S~n~itisgify Switch in the 1.4V position. REF 1 meas u m 78VAC, &2,3 7 VAC, st the amplifier output. REF I! measure 52.9 VACFA 1.6 VAC, at the amplifier output*
Figufe 5.2 DiF@r@nZia$ed Square Wave
5,10Level C~ntrsls
S@@s: kevef cantroiled by level controls, Inltlairl Conditiows: Controls per standard. Bre@adur@: Laad, lnject a % kHz sine wave. With No level controls fully clockwise you should see futf gain, As controts are rotated eountercixkwise, sbsewe sirniIiar gain reduetisn in each channel, &$hen complete, return !eve8 contrsls $0fully clockwise pssitian,
5.12 Slsw Rate & 10kHz Square Wave
Spac: REF 1 - 3 d V/pS. 2 3
REF I f -1 9 ~3 V&S.
5,lf Current Limit
Spec: REF 1 ---Current fimit at 43 amps, 3 amps. 2 3 REF II -Current limit at 30 amps, k3 amps, lnrtlal Csndftians: ConWols per standard. Procad&~s: Load each channel ta 7 Ohm. Inject at "I kHz differentiated &ear3 % duty cycte) square wave. 8 See Figure 5 %. Insrease output level until current limf iting occurs, Refer $0Figure 5 2 for wave Form. REF f will limit (clip) at 43 vstt peak, 2~3 voltss. REF II will limit (clip) at 38 v~iwpeak, volts, k3
lnltrai eondltlo~s:Cantrsls per standard, F~ecedurg:Laad each ~hawwel 8 sk~rns. to inject a 10 kHz square wave at a level of 2 ts 5 volts below clip. Observe the slope af the waveform and catculate the sllew rate, Any ringing must die out in lass than "44 of the period, and its amplitude must be less then 2% a f O %be waveform amplitude. See Figure 5.3.
In
I
Out
Figure 5.3IQ kHz Square kVave
Electrical Checkout 5-2
Checkau
Injt[g[ C@nd[tisns: Controls per standard. T~rmi~ai;e input of channal not driven with 800 ohms, P ~ @ ~ @ @ u Pohm load on each channel, Inject a 20 8 @: kHz sine wave into the ehannei 1 input and inereass sutput level to full pawer (REF f =78 VAC, REF 11 =52 VAC)* For REF l measure less than 78 mVAC at the output of channel 2, REF s measure less than 52 For i mVAG at the output o channel 2. Repeat by injecting f the signal into channel 2 and measuring channel 1.
Procedures
Prccedure Shed: inject a 6QHz sine wave. REF I output level = 46 VAC. REF I! output fewel= 28 VAC. After
s~@@:at 20 kHz, -6048
5.13 Crosstalk
5.14 Output Power For 12@V @@Hz enftg: Spec sf 8 OAm Stereo: REF I z 780W a"lQ.62%THO,
REF fl 2 355W at 8,82%THB. Spas st 4 Ohm S ~ ~ P BREF I r 1'I Q: 60W at O-02%THD. REF if a 555W at 0,02%THD, Far lntsrnatignal50Hz unl%: %peegt 8 Ohm %tare@: Ii a 7750W at O,S % THD, REF REF I f a 355W at 0.19 TWD, & spec af 4 Ohm B8t@reo:REF i 2 1095W at 8.1% I H D . REF : 1 2 535W at 0.1% THD, Inlt%al C@@difi@~$:: Controls per standard. Proced~re:Load each channel tea 8 ahrns. lnject a 1 kHz s i n s wave and measure output power?at speeified TWD, with both channels driven. Next, load each channel to 4 ohms, Inject a 3 kHzsine wavg and measure output pawer* at specified THD, with both channefs driven.
Figure 5.4Inductive Load Cojd
5,15 RsaeSIve Loads
Spge: No oscillations. Safe with ail types of Soads. llnltlal C@nd%Olons: Controls per standard. Procadurn Capaeitiue: Load each channel to 8 ohms in parallel with 2 yE Inject a 2 kHz sina wave, REF I 9 output ievei = 45 VAC, REF II sutput level -- 30 VAC. Drive load for 10 seconds> oseiliations. No P r o e e d ~ Onductiv~:Load each channel 1 8 ohms in r~ s parallel with 159 yHenriss. Inject a 1 kHz sine wave, REF I output level = 36 VAC* REF f I satput Ieval = 28 VAC, See Figures 5,4 and 5.5 for typical wavsform shapes, Test duration is 5 sscsnds. ProseBure To@uf@: Load each channel with Zhs primary (red and black Beads) sf a PSU transformer $D70405 ,inject a 20 Hz sine wave into each channe!, REF I 1 output level = 40 VAC* REF 1 1 output Ievd -- 375 VAC. Observe 3 to 7 flyback pulses in both polarities, Test duration is 10 seconds, See Figure 5,6 typical far waveform shape,
I
Electrical Checkout 5-3
Checkou
Procedures
5,16 ODEP Limiting Spss: No ascillatisn on ODEP Limiting wave form\ QDEP LED dims and Is out as the amplifier starts QDEP fimiting.Either channel esntrols limiting in ParatiefMoue
Mode. initsat Con@itlong:Centrals per standard; rag or other obstruction blocking fan so that it does not turn. Ftacedufe:: Load the amplifier to 4ohms ou each channet, Inject a sine wave with the same frequency as the AC power line. REF i output level .-- 40 VAC. REF I! &a~fpkifleve128VA6, After a few minutes observe a = wave form similar to Figure 5'9. Remove the input signal from both channels and ailgaw the amplifier to cogs! for a few minutes. Switch the amplifier ta Paraltsi Mono and remove the load from channel 1. inject the si~nal Ento channel 1 and obsarve that QDEP limiting occurs a the output BE both channels. Remove the load from t channel 2, and instail the load an channef 3. Again, observe that bath channels lirnik Return all amplifier controls $0standard initiaf conditions. Remove the fan
5.17 Mute and Turn On Delal
Sp@@: Clamps signal; 3 ts 5 second turn on delay, initisi Coadition%:Controls per staradard, PP@@@$u~@: NO load. inject a 1 kHz sine wave into both channels. Observe the output signal with an assillpascope. Turn the amplifier off with the front panel switch. The amplifier should clamp the signal, not allow it to decay with the pswer supplies. Turn the amplifier back an and observe the 3 to 5 second deiay beforeit comes back out of standby"Note thal both channels may not come out of standby at the exact same time.
5.18 Low Frequency Proteclion
$ I : Ampiifier gwutas for low frequency, @@
obstruction.
5 seconds.
InibIail C~nditions:C~ntrols standard, per Frocgdure: No /sad. Inject a 0.5HZ 12 voft peak-topeak square wave, a 2 Hz " ppgak-to-peak sine I wave into each channel, one channel ak:a time, and ygpify tnat $hechannel driven cycles into standby*once in standbysit will lay to cycle o t of standby every 3 to u
Electrical Cheekoast 5-4
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5.19Signal to Ncise Ratio
Sgse: REF I 120dB, A weighlsd, REF 11 117 dB, A wwsighbed,
Procedures
of each channel.
5.20 !ntarmeduiali@n ai%t@@$a@
Spec at O dB Oatp~t (Fgil Powsr]: 8.005%. 8p@s -35 db Output:: 0.02%+ at Inltia1 Cowdltlons;: Controls per standard,
5.24 Turn OH Trsnsients spas: Na dangsr~us transients.
laitis! GonditisnsX~ontrsls standard. per Pro~8lure:From an on condition, turn sff the amplifier and monitor the output noise at the time of turn 08.
35 dB and measurE less than 0.02% IMD,
5,21 hEB Funstions
switch is engaged,
ODEP limit,
5.22 Display Set-Up
Sp@g;Ladder displays balance each other; OadicaWors oilurninate at output voltages per chart below, initial Gssditlo~s:ConlroBs pea standard. Meter Mode Switch i the Bu%put n Leve! positioa. Prosedurs: With the display set to read output Bevel inject a 1 kHz sins wave into both channels of the amplifier- Adjust the level se that the -18 dB LEDs puke an and OM. Adjust R78sn "Ihe display board until the Ch 1 and Ch 2 -10 dB LEDs pulse a the same fraquency* t Note: "I"@ complete front panel needs to be disassembled in order to access the display board. Next, verify t h a h e a h indicator illuminates per the chart
below.
Eiiestrical Checkout 5-5
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Electrical Checkout 5-6
6 Schema
Schematics 61
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Schematics 6-2
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7,1 General Ilnfo~matian
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5 Terms
Normal terms are pre-paid, Net-30 days applies to 0 1 y 11 those firms having pre-established a~caknnts with Crown. If pre-paying, the order must be packed and weighed before a total bill can be estabJisked, after which an amount due will be issued and shipment made upon r@ceipla$ pre-payment, New parts returned $orcredit are subject fs a 1 % re-stocking fee, 0 authorization from the Crown Parts Department must be obtained before returning parts for credit.
The Crown Parts Department is not a general parts warehause. Parts sold by Crown are solely For servicing Grown products,
This chapter confairas il[usiratisns and parts lists for the Studio Reference ampfifi*ers. The parts lists in this chapter are for all mechanical parts and parts not iwcluded on a module (circuit board). Chapter 8 CODtains artwork and parts lists For af modules. l
7.2 Standard md Spe~ial Parls
Many smaller electrical and elsctronic parts used in ths Studio Wefersnce amplifiers are stacked by, and avaiiabfe from, electranie supply houses, However, some electronic parts that appear to be standard are actually speerial, A part ordared from Crown will ass u r ~ acceptabje replacement.Structural items such aa~r as covers and panels are available only from Crown.
7.3 Ordering Pads
When ordering parts, be sure to give the amplifier model and serial number at-ed include a description and Crown Part Number (CPN) from the parts listing. Price quotes are available on request.
I
Part prjces and avai!abi/ityare S U ~ ~ @to c h a n g ~ C$ withour notice.
7,6 Illggtrated Pa@$Lists
Contained within this section are the illustrated parts lists far the Studio Reference B and I & amplifiers, The electrical and elec"lrsnic parts in ths assembly drawings are referredto by Crown Part Number $@PN),and quantities used are indicated. Thosa parts are also shswn in the circuit schematics {chapter6 , 1 and are idoatified there by circuit designation.
7.4 Shipment
Shipment wfif be normally mad^ by UPS or best other method unless you speciQ %,thewise. %hipm.wenls are made $0and from Elkhart, IN, only. Established accounts with Crown will receive shipment freight prepaid and will be billed, A 1 others will re~eive 1 shipment on a C,O,D.pre-payment (check or credit card) s r
basis,
Crawn
P a ~ Department s
MailingAddress: PO Bsx 1080 Efkha~? USA 46$"s5-100$$ IM
Plant 2 SxWe 1 % W, Mishawaka Rd, 9 EQkhaa, USA 48519 %N
Phone: (219)294-8280 $obi E r e : (Ma)M24939
Parts fnfarmation 7-1
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Studs Refercs?r_;le Service Manual ",."--- ,".-"-,,..,
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Parts Information 7-2
1
$crew,8-32 .75FLSHD x
End Cap Handls
End Cap
2
3
4
Screw,8-32 x 0.5 FLTHD
Handlss
5
Main Chassis
Hoidea;Gablo Fishpaper SCFGW, 6-32 x .3f 2 QNHB T15
6 9
Display Brkf
8
#8 Star Washer
DPDT On/Off Push Button Switch
9
10
31
Screw,6-32 x 318 PNHO TrI
SCWW, 4.40 x 395
Covers, etc. OnlBfF Switch
22
13
Screw,6-32 .3125 x
Dtsplay Module, REF I
Display Module, REF I I
Display
14
Pot, 5K ohm Linear 3 Det. 1
t solatsf? LED Foam
2 5
16
Display Bracket
37 18
Front Pane!, Top Extrusion
Overlay, REF t
Overlay?REF i l
19 Air Filter
20
21
Screw!8-32 x -37 WDWB
#8 Star Washer
Btm Extrusion
2 2
23
24
Front Panel, Bottom Extr~aion
Finger Gr~ard
Knob
Set Screw, 6-32 ,I8 x
Sub Front
Level
Level Knobs
Not Shown
Screw, 8-32 x .5 PNHD Taptits
Mandlas
2 5
Push Button
On80ff
Parts Information 7-3
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Studio Referer7ce Service Manual
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Parts information 7-5
@crown*
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Studio Refergnee Service Manual -,- -.P
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Parts lnfsrmatiorl 7-6
Studio Reference Service Manuaf
Screw, 8-18x 1.375 PNWD
Main Madufe
811%02 $08182
Spacefx3 7 5 Toggle Nut Plastic
Board Support, 7$8Lock
Screw, 6-32 x -3f 2 Par? Hd. T15
Clamp, TO-22On8-3P
Output Assambly
crew, 6-32 x .56 Washer Head T ? 5
1 x .625 Rubber Grommet
Back Pan& Assembly
W8sher8 112 Steel
Power Transfarme& REF 1
POW@% Tran~forrner, I! REF
$crew, f 12-20 x 4 Hex Cap
I
I
i
Parts information 7-7
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Studio Reference Service Manua$
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Back Pane
Bask Panel Plate Shield, Circuit Breaker
Screw, 8-32 38 PNHD x
Screw, 6-32 .25 x
WasherEW lnt, Shar 6
REF I Circuit Breaker$30A REF I! Circuit Breaker) 288
Strain Relief
Pip Cage Assom bty
Dual Binding Past, Gald PItd
Jumper, 2 Position
Wire, # I 2
BLK 22 in,
Wire, #I2 BkK 15 in,
Wire?#12 RED 20 in.
Wire, R 12 RED 13 in.
Solder Lug, #8 Hole
Jumper, Four Output Ground
PIP-FX input Connector
Washer* #8 Star
Screw, 8-32 w 37 RDHB
REF I Power Cord, 10-3m30P
A f W86-70806
A1 1993-Q587F
REF II Powss Card, 12-3 Wd15A
Parts Information 7-9
SCYGW, x "332T I 5 8-42
NPN Power Transistor$REF I
NPN Power Transistor, REF II
PNP Power Transistor* REF
I
PNP Power Transisto6 REF II
Meatsink with Fins, REF I
Haatsink with Fins, REF f t
Sil Pad, 237 x 1457 7 Mil
Parts information 7-7 f
Pa& Infarmalion 7-12
Rev" 0 -
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Studio Ref@r@bac@ Service Manual , , - , . " . - %
,
,
P
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Capacitor, 6 0 yF 150V (REF 9) 30
Capacimtail, 406300pF 186V (REF I!)
Shoulder Wssk-rer
Washee; "Id" 'Believille Spring
Lack Washer* #I0 Inl, Tooth
Wire, W 6 Blue (Gh 1) 1 Wire, # 6 Blue (Ch 2 1 ) Wire, #16 Wed (Ch I )
Wire, #I8 Red 4 R 2) 6
Screw, 10-32 .5 x
A f 0088- 008 27
Parts Informatian 7-3 t
Parts informahian 7-1 4
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Studio Reference Service Man~~sf ------- ~-"-".~..."...,~,". ....
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Rev. 0
This page intantionalty left blank
Parts Infarmatian 7-6 f
Studio Refereace amplifiers, there has been several updates and revisions.
list:af madules is comptete up tu this date,August 1 9 . 96
Fallowing the module information is the parts list for each mada6le. Iwctuded in the parts list is a map isca,,
output module built on PC board P10423-
Csntrst Msduie:
I.% on PC board O 8165A7. . For parts list see page
k on PC board O 8853t Far parts Iist see page
nation. Belaw is a code ts help detarmine what type af part each designatloas is:
itt on PC board D 9099-9.
For parts list see page
C = Capacitor D -- Diode
E = LED HW -. Hardware J = Sack& or connector K -- Relay L z Inductor N = Resistor Netwark
display module built an PC board D 79486. For schematic see For parts list see page
8 3 Studis Rsfe~enceIModute Informatisn . I
Main Module: on PC board B 8688-Q, FOBparts list see page
marn moduls built on -7, schsmalic see For :st see page 8-28, output module built an
P = Terminal
Q .-- Transistor R Resistor S -- Switch TP -- Test Point
X Z
-
U = fntegrated Circuit -- M i s ~ ,
z
Jumper
PC bsard P10423-
them w il be two map iocaklans,The first for channel 1 w and the seesnd for channel 2.
~antral fnadui@ on PC board D B"I5SA4. built For parts list see page
Far parts list see page
8-2 Studio Wef@rsnca m@d@!@ i fnfarmatlen
Main Module:
m - 2c~nlral module built ou PC board D 9099-9. For schematic sca . For parts list see page
see page 8-2.
It on PC board D 9940Far parts list see page
Module Information 8-2
. ..
1 E 1 0 2 0 C 98570/0 EIQ1/261 G9857-1
HW16
Wed LED Wed LED
J5/F5 J6/F6
HW17 HW48 HW29
C 8812-7 C 883 2-9 C 8812-7 C 8832-7
5.5" Cable Tie 5.5" Cable Tie 5+5'T~abiee fi 5.5" Cable Tie
A5
B5 N5
65
H4 11jG1 I1BG1
J2 C 4508-5 J 100i200 C 8432-4 J 10OXf200X C 6778-2
3580
J600 J7QO J8QO
D 8395-2
B 8397-8 B 8399-8 D 8395-2
16 Pin IC Ski. 3CondPhJk PhJkCsver 7,75"I2pin Gbl 2.5" 12pin Cbl
0%
N5 2.5" 12pin Cbl B5 7,$5"12pin 6bl A5
N101B201 D 8248-3 7 pin Rss Net N3021202 B 6082-8 Res Net-C N3 8 A1281A --- NsW~sed 1 --N 1Ol&/201 --- Not Used --B N102C/281@--- Nat Usad --N101Dl201El Not U5ed NJ 01E/2QS E --- No%Used --N 1QIF/20 F ---- N QUsed --I ~
*I+
PI P6 ~ 1 1
@ 7593-4
e 7593-4
C 7592-6
C 8418-3
PI2
P101/201
--- Nc~t --Used
5pas H ~ a d e r H2 3pas Header H2 ~ p o Headef H5 s
64
4pos Header 3 ViFI
AJ0265-18021 10Ml% A?Q265-"IQ521 18.5K1% --- No%Used --A 10266-433"143K 5% A.dO265-7502W5M 1% --- Not Used ----- Not Usad ----- Not Used --A ?0265-75021 75K 1 % A16266-433? 43M 5% A10266-2872 2.7 5?&.5W --- Not Ussd --A18265-10273 f,62K 1% Al0266-5111 5105% A10265-28523 20.5K 1% 1W A"f025-226711 2,67K 1% A"IQ25-26911 2.6'7K l % Al0265-"11821 I 1.&K 7 5% 8% 0266-683t 68K 5% AI8266-8212 8205% A18266-9"11 9"Q% A2 0266-6831 68K 5% A18265-11821 31+8f% A10265-4992Mg9.9K % ^6 AlQ265-48"$ J4,87K I % 1 AlS266-1521 1,5K 5% A"BQ26-5141 51QK 5% A10266-335t 3.3M 5% A1 6266-4931 47K 5% A1 0265-40281 4 % 1 % 8 A10265-12?11 1,21K 1% A10265-40201 482 176 C 5062-2 10BK LIN P8T A 10266-274 1 27BK 5'h A 10266-2832 20K 5% .5W
++ +,