® 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™ are trademarks and Crown ,® IOC ®, ODEP,® IQ System ® and P.I.P.
3 YEAR THREE YEAR FULL WARRANTY 3 YEAR 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.
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.
Studio Reference I & II Professional Studio Amplifiers CONTENTS 1 Welcome .......................................................................... 7 1.1 Features ................................................................... 7 2 Facilities .......................................................................... 8 3 Installation ..................................................................... 10 3.1 Mounting ................................................................ 10 3.2 Cooling ......
Studio Reference I & II Professional Studio Amplifiers ILLUSTRATIONS 1.1 2.1 2.2 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 4.1 4.2 4.3 4.4 4.5 5.1 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 7.1 7.2 8.1 Studio Reference I Amplifier ........................................... 6 Front Facilities ................................................................. 8 Rear Facilities ................................................................. 9 Mounting Dimensions .................
Studio Reference I & II Professional Studio Amplifiers ® Fig. 1.1 Studio Reference I 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 company immediately. Only you, the consignee, may initiate a claim for shipping damage. Crown will be happy to cooperate fully as needed. Save the shipping carton as evidence of damage for the shipper’s inspection.
Studio Reference I & II Professional Studio Amplifiers 1 Welcome The stunning realism you will experience when listening to a Crown Studio Reference ™ amplifier will redefine your expectations. The evolution of this studio standard ushers in a new 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.
Studio Reference I & II Professional Studio Amplifiers A BCD DCB A E F ® G H 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 thermodynamic energy.
Studio Reference I & II Professional Studio Amplifiers Fig. 2.2 Rear Facilities I. Reset Switch N. Stereo / Mono Switch This back panel switch can be used to trip and reset the AC mains circuit breaker (see Section 4.3.4). This switch is used to select one of three operating modes.
Studio Reference I & II Professional Studio Amplifiers 3.2 Cooling 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 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. ® 7 in (17.
Studio Reference I & II Professional Studio Amplifiers you may want to install supplemental cooling like a rack-mounted blower or an air conditioner. FRONT OF RACK BLOWER (OPTION 2) AIR FLOW A “squirrel cage” blower can be installed at the bottom of the rack so it blows outside air into the space between the door and the front of the amplifiers. This will pressurize the “chimney” behind the door (Figure 3.4, Option 1).
Studio Reference I & II Professional Studio Amplifiers 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. mode, turn it off, slide the stereo/mono switch to the center position, and properly connect the output wiring as shown in Figure 3.5.
Studio Reference I & II Professional Studio Amplifiers greatly degraded. Also, turn down the channel 2 level control (fully counterclockwise). is very different from the other modes and requires special attention. Note: The channel 2 input and level control are not defeated in Bridge-Mono mode. Any signal feeding channel 2 will work against the channel 1 signal, and usually results in distortion and inefficient operation.
Studio Reference I & II Professional Studio Amplifiers 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 most devices. Phone jacks are provided 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.I.P.
Studio Reference I & II 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. 470 ohms + A Balanced In + .
Studio Reference I & II Professional Studio Amplifiers power cables and power transformers. We also recommend using shielded or twisted pair wire. With loose wires, use tie-wraps to bundle together each pair of input wires. This helps reduce magnetically-induced current by minimizing the cross-sectional area between 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.
Studio Reference I & II 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 loudspeakers for the Zs in the equation. When finished, mark your answer on the nomograph’s “Load Resistance” line. Total Load Resistance in Ohms = (1¦ Z1 + 1¦ Z2 + 1¦ Z3…)–1 2. Select an acceptable damping factor and mark it on the “Damping Factor” line.
Studio Reference I & II Professional Studio Amplifiers available from most electrical supply stores. 3.3.6 Additional Load Protection Studio Reference 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 overpowering and mechanical damage from large transient voltages. In both cases, fuses may be used to protect your loudspeakers, or you may opt for the convenience of a P.
Studio Reference I & II Professional Studio Amplifiers 4 Operation 4.1 Precautions Although your amplifier is protected from internal and external faults, you should still take the following precautions for optimum performance and safety: 1. Improper wiring for the Stereo, Bridge-Mono or Parallel-Mono modes can result in serious operating difficulties (see Sections 3.3.1 through 3.3.3). 2.
Studio Reference I & II Professional Studio Amplifiers The green signal presence indicators flash synchronously with the amplifier’s output signal. The signal detector is connected to the signal path after the input gain stages and level 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.
Studio Reference I & II Professional Studio Amplifiers and transformer thermal protection. These systems will prevent amplifier damage in virtually any situation. 4.3.1 ODEP Crown invented ODEP to solve two long-standing problems in amplifier design: to prevent amplifier shutdown during demanding operation and to increase the efficiency of output circuitry.
Studio Reference I & II Professional Studio Amplifiers former than in the output devices. This can overheat the transformer and activate its protection system. Studio Reference amplifiers are designed to keep working under conditions where other amplifiers would fail. But even when the limits of a Studio Reference amplifier are exceeded, it still protects itself—and your investment—from damage. 4.3.
Studio Reference I & II Professional Studio Amplifiers METER ON/OFF SWITCH OFF ON ® 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 I and 2.7 volts for the Studio Reference II. If needed, it can be switched to a sensitivity of 0.
Studio Reference I & II Professional Studio Amplifiers 5 Technical Information 5.1 Overview Studio Reference amplifiers incorporate several new technological advancements including real-time computer simulation of output transistor stress, low-stress output stages, an advanced heat sink embodiment and the Programmable Input Processor (P.I.P.) expansion system. Custom circuitry is incorporated to limit temperature and current to safe levels making it highly reliable and tolerant of faults.
BALANCED 1/4" PHONE P.I.P. Fig. 5.
Studio Reference I & II Professional Studio Amplifiers output signal and the input signal from the gain pot, and drives the voltage-translator stage. From the error amp, the voltage translator stage channels the signal to the Last Voltage Amplifiers (LVAs) depending on the signal polarity. The +LVA (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.
Studio Reference I & II 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 0.02% THD and noise. Standard 1 kHz Power: refers to maximum average power in watts at 1 kHz with 0.1% THD and noise. Full Bandwidth Power: refers to maximum average power in watts from 20 Hz to 20 kHz with 0.1% THD and noise.
Studio Reference I & II Professional Studio Amplifiers Sensitivity: A three-position switch inside the P.I.P. compartment used to select the input sensitivity for both channels: 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.
Studio Reference I & II Professional Studio Amplifiers 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.
Studio Reference I & II Professional Studio Amplifiers 100 VAC, 50 Hz FTC Continuous Average 0.1% THD+N (See note 1) Stereo 4 565 495 560 555 470 (both channels driven) 8 360 340 355 360 340 Bridge-Mono 8 1,145 1,020 1,130 1,105 960 720 690 715 720 680 Stereo/Mono Mode (balanced output) 16 Parallel-Mono 0.1% THD+N (See note 2) 0.05% THD+N (See note 3) 0.
Studio Reference I & II Professional Studio Amplifiers Maximum Power Specifications Crown’s maximum power specifications represent the largest amount of output power you can expect from your amplifier 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.
Studio Reference I & II Professional Studio Amplifiers 120 VAC, 6 0 Hz Stereo/Mono Mode 100 VAC, 50 Hz Single Cycle Tone Burst 40 Millisecond Tone Burst 0.05% Distortion + Noise (See note 1) 0.
Studio Reference I & II Professional Studio Amplifiers +2 +1 0 1 watt –1 8 ohm –2 dB 4 ohm –3 –4 –5 –6 –7 10 100 1K 10 K 100 K FREQUENCY (Hz) Fig. 6.5 Typical Frequency Response 100,000 10,000 DAMPING 1,000 8 ohm 100 10 20 100 1K 10 K 20 K FREQUENCY (Hz) Fig. 6.6 Typical Damping Factor 1 0.1 8 ohm OHMS 0.01 0.001 0.0001 20 100 1K 10 K 20 K FREQUENCY (Hz) Fig. 6.
Studio Reference I & II Professional Studio Amplifiers +135˚ +90˚ +45˚ 0˚ –45˚ –90˚ –135˚ 20 100 1K 10 K 20 K FREQUENCY (Hz) Fig. 6.8 Typical Phase Response 0 –20 –40 dB –60 –80 –100 –120 20 100 1K FREQUENCY (Hz) Fig. 6.
Studio Reference I & II Professional Studio Amplifiers 0 –20 –40 dB –60 Studio Reference II –80 Studio Reference I –100 –120 20 100 1K 10 K 20 K FREQUENCY (Hz) Fig. 6.
Studio Reference I & II Professional Studio Amplifiers 7 AC Power Draw and Thermal Dissipation Here are the equations used to calculate the data presented in Figures 7.1 and 7.2: 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.
Studio Reference I & II Professional Studio Amplifiers Studio Reference II L O A D 8 Ohm Stereo / 16 Ohm Bridge-Mono / 4 Ohm Parallel-Mono 4 Ohm Stereo / 8 Ohm Bridge-Mono / 2 Ohm Parallel-Mono Duty Cycle AC Mains Power Draw (Watts) 50% 645 7.8 40% 535 6.4 30% 425 20% 10% Current Draw (Amps) Thermal Dissipation 100-120 V 220-240 V btu/hr kcal/hr AC Mains Power Draw (Watts) 3.5 970 245 975 11.7 2.9 840 215 795 9.6 5.1 2.3 705 180 620 315 3.8 1.7 575 145 205 2.4 1.
Studio Reference I & II Professional Studio Amplifiers 8 Accessories 8.1 P.I.P. Modules One advantage of Studio Reference amplifiers is the ability to customize them using P.I.P. (Programmable Input Processor) modules. Each amplifier is equipped with an edge card connector inside the back panel P.I.P. compartment. The modules install easily: compressors activate when a signal will clip the input, an IOC error occurs, or the output exceeds the selected threshold.
Studio Reference I & II Professional Studio Amplifiers pressors, it only compresses the signal to prevent overload. It can deliver up to 13 dB of additional headroom without being noticeable. PA – + – LINE + MIC CH-2 MIC LEVEL CH-1 REMOTE MIC LEVEL – ISO CH-2 INPUT + CH-1 INPUT – + + – MIC CH-2 INPUTS + LINE CH-1 INPUTS Programmable Input Processor (P.I.P.) – —WARNING— THIS P.I.P.
Studio Reference I & II Professional Studio Amplifiers 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 servicing to a qualified technician. 9.1 Worldwide Service Service may be obtained from an authorized service center.
Studio Reference I & II Professional Studio Amplifiers Crown Factory Service Information Shipping Address: Crown International, Inc., Factory Service, 57620 C.R.
