Summary of the content on the page No. 1
®
THE PROFESSIONAL AUDIO DIVISION OF CROWN INTERNATIONAL, INC.
®
®
Exported to select countries as Amcron.
™
Studio Reference
PROFESSIONAL STUDIO AMPLIFIERS
OWNER’S MANUAL
©1995 by CROWN INTERNATIONAL, INC.
P.O. Box 1000, Elkhart, Indiana 46515-1000
Telephone: 219-294-8000
Printed on
recycled paper.
™ ™ ™ ™ ™ ™
Trademark Notice: Studio Reference, Smart Amp, MPX-6, SMX-6, AMB-5, and grounded bridge K80604-0
® ® ® ® ®
8/95
are trademarks and Crown, IOC , ODEP, IQ System and P.I.P. are registered
Summary of the content on the page No. 2
3 YEAR THREE YEAR FULL WARRANTY WORLDWIDE NORTH AMERICA SUMMARY OF WARRANTY SUMMARY OF WARRANTY The Crown Audio Division of Crown International, Inc., 1718 West The Crown Audio Division of Crown International, Inc., 1718 West Mishawaka Mishawaka Road, Elkhart, Indiana 46517-4095 U.S.A. warrants to you, Road, Elkhart, Indiana 46517-4095 U.S.A. warrants to you, the ORIGINAL the ORIGINAL PURCHASER and ANY SUBSEQUENT OWNER of each PURCHASER and ANY SUBSEQUENT OWNER of each NEW Crown 1 NEW Crown prod
Summary of the content on the page No. 3
The information furnished in this manual does not include all 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. 10
Summary of the content on the page No. 4
Studio Reference & Professional Studio Amplifiers CONTENTS 1 Welcome.......................................................................... 7 1.1 Features ................................................................... 7 2 Facilities .......................................................................... 8 3 Installation ..................................................................... 10 3.1 Mounting ..........................................................
Summary of the content on the page No. 5
Studio Reference & Professional Studio Amplifiers ILLUSTRATIONS 1.1 Studio Reference Amplifier ........................................... 6 2.1 Front Facilities ................................................................. 8 2.2 Rear Facilities ................................................................. 9 3.1 Mounting Dimensions .................................................... 10 3.2 Removing an End Cap .................................................. 10
Summary of the content on the page No. 6
Studio Reference & Professional Studio Amplifiers ® 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 ini- tiate 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 inspectio
Summary of the content on the page No. 7
Studio Reference & Professional Studio Amplifiers 1 Welcome traditional amplifiers. This results in significantly lower The stunning realism you will experience when listen- ™ distortion and superior reliability. ing to a Crown Studio Reference amplifier will ® redefine your expectations. The evolution of this studio ❏ Patented ODEP (Output Device Emulation Protection) circuitry detects and compensates for overheating and standard ushers in a new era of powerful, ultraquie
Summary of the content on the page No. 8
Studio Reference & Professional Studio Amplifiers A B C D D C B A E F ® GH Fig. 2.1 Front Facilities 2 Facilities cators may not flash at very low input signal levels. See A. Level Controls Section 4.2. Each channel’s output level can be adjusted accurately using the 31-position detented level controls on the front E. Enable Indicator panel (see Section 4.4). This indicator lights when the amplifier has been “en- abled” or turned on, and AC power is available. B. ODEP Ind
Summary of the content on the page No. 9
Studio Reference & Professional Studio Amplifiers Fig. 2.2 Rear Facilities N. Stereo/ Mono Switch I. Reset Switch This switch is used to select one of three operating This back panel switch can be used to trip and reset the modes. Stereo mode is used for normal two-channel AC mains circuit breaker (see Section 4.3.4). operation, Bridge-Mono mode is used to drive a single J. Power Cord channel with a load impedance of at least 4 ohms, and For 120 VAC, 60 Hz North American
Summary of the content on the page No. 10
Studio Reference & Professional Studio Amplifiers 3.2 Cooling 3 Installation Your amplifier has an internal variable speed fan that is 3.1 Mounting controlled to match the unit’s real-time cooling needs. With proper installation and typical studio use, the fan Studio Reference amplifiers are designed for standard may never need to run. For best results, you should fa- 19 inch (48.3 cm) rack mounting or stacking without a miliarize yourself with its cooling requirements. ca
Summary of the content on the page No. 11
Studio Reference & Professional Studio Amplifiers FRONT you may want to install supplemental cooling like a AIR BLOWER OF FLOW (OPTION 2) RACK rack-mounted blower or an air conditioner. DOOR 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, EQUIPMENT Option 1). The blower should not blow air into or tak
Summary of the content on the page No. 12
Studio Reference & Professional Studio Amplifiers making connections, selecting sources and controlling mode, turn it off, slide the stereo/mono switch to the output levels. The load you save may be your own! center position, and properly connect the output wiring Crown is not responsible for damaged loads that result as shown in Figure 3.5. Each output channel has two from carelessness or deliberate overpowering. sets of binding posts to make it easier for you to con- nec
Summary of the content on the page No. 13
Studio Reference & Professional Studio Amplifiers greatly degraded. Also, turn down the channel 2 level is very different from the other modes and requires control (fully counterclockwise). special attention. Note: The channel 2 input and level control are not de- To select Parallel-Mono mode, turn off the amplifier and feated in Bridge-Mono mode. Any signal feeding chan- slide the stereo/mono switch to the left (as you face the nel 2 will work against the channel 1 signal
Summary of the content on the page No. 14
Studio Reference & Professional Studio Amplifiers 3.3.4 Input Connection – + The balanced inputs have a nominal impedance of Note: If two or more channels with the same input ground reference 10 K ohms (5 K ohms unbalanced) and will accept the 3 are driven from the same 1 2 INPUT floating source, connect line-level output of most devices. Phone jacks are pro- Floating only one shield to the source chassis. source vided on the back panel, while the factory-installed P.I.P.-
Summary of the content on the page No. 15
Studio Reference & Professional Studio Amplifiers 470 ohms SOLVING INPUT PROBLEMS + + .0056 Sometimes large subsonic (subaudible) frequencies Balanced In A Balanced Out µ f are present in the input signal. These can damage – – 470 ohms loudspeakers by overloading or overheating them. To 1.8 mH attenuate such frequencies, place a capacitor in series + + with the input signal line. The graph in Figure 3.11 .015 B Balanced In Balanced Out µ f shows some capacitor values and h
Summary of the content on the page No. 16
Studio Reference & Professional Studio Amplifiers power cables and power transformers. We also recom- the damping factor decreases as the cable resistance mend using shielded or twisted pair wire. With loose increases. This is very important because the ampli- wires, use tie-wraps to bundle together each pair of in- fier’s excellent damping factor can be easily negated put wires. This helps reduce magnetically-induced by using insufficient cable. current by minimizing the
Summary of the content on the page No. 17
Studio Reference & Professional Studio Amplifiers 1. For loads connected in parallel, use the equation that amplifiers share a common cable tray or jacket, follows to calculate each channel’s total load resistance. use tie-wraps to bundle individual conductors so Substitute the rated impedance of the connected loud- the wires for each loudspeaker are kept close speakers for the Zs in the equation. When finished, mark together. (Do not bundle wires from different your answe
Summary of the content on the page No. 18
Studio Reference & Professional Studio Amplifiers available from most electrical supply stores. A better approach is to fuse each driver independently. This allows you to apply the most appropriate protec- 3.3.6 Additional Load Protection tion for the type of driver being used. In general, low- Studio Reference amplifiers can deliver very high frequency drivers (woofers) are most susceptible to power levels, so it’s a good idea to add protection for thermal damage and high
Summary of the content on the page No. 19
Studio Reference & Professional Studio Amplifiers 4 Operation 4.1 Precautions Although your amplifier is protected from internal and external faults, you should 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). Fig. 4.1 Indicators 2. When driving an inductive load like an electrostatic power supply
Summary of the content on the page No. 20
Studio Reference & Professional Studio Amplifiers As dynamic range meters they show each channel’s The green signal presence indicators flash synchro- ratio of peak-to-average power in dB. The dynamic nously with the amplifier’s output signal. The signal de- range may be low for sources like AM/FM radio or low- tector is connected to the signal path after the input quality recordings. Other sources like live music or gain stages and level controls, so a flashing indicator
