Crown PB Series Powerbase 1 Power Amp 100 Watts User Manual

Crown PB Series Powerbase 1 Power Amp 100 Watts User Manual

Product Information

Models

The Power Base-1, Power Base-2, and Power Base-3

Applies to

120V AC North American PB-1, PB-2, and PB-3 units with the following markings: E106377, LL 32521C, 101229-1 12/96

Warranty

A full warranty is provided for three years from the date of purchase by the original purchaser and any subsequent owners. The warranty covers defects in materials and workmanship, and the product will be repaired, replaced, or refunded if it fails during the warranty period. The warranty does not cover intentional misuse, accidents, negligence, or loss covered by insurance, nor does it cover products with defaced or removed serial numbers.

Product Usage Instructions

1. Ensure that the Power Base unit is plugged into a wall outlet that provides 120V AC power.
2. To turn the Power Base off, press the power button three times.
3. If a defect occurs during the warranty period, contact an authorized service center to have the product repaired or replaced. If a refund is elected, return the defective product free and clear of all liens or other encumbrances, and a refund equal to the actual purchase price (less depreciation) will be issued.
4. Do not intentionally misuse the Power Base unit, as this will void the warranty.

© 1996 by Crown International, Inc., P.O. Box 1000, Elkhart, Indiana 46515-1000 U.S.A. Telephone: 219-294-8000. Power-Tech amplifiers are produced by the Professional Audio Division of Crown International, Inc. Trademark Notice: Power Base-3™ is a trademark and Power Base-1®, Power Base-2 ®, Crown,® IOC ® and ODEP ® are registered trademarks of Crown International, Inc. Other trademarks are the property of their respective owners.

THREE YEAR FULL WARRANTY

WORLDWIDE

SUMMARY OF WARRANTY
The Crown Audio Division of Crown International, Inc., 1718 West Mishawaka Road, Elkhart, Indiana 46517-4095 U.S.A. warrants to you, the ORIGINAL PURCHASER and ANY SUBSEQUENT OWNER of each NEW Crown1 product, for a period of three (3) years from the date of purchase by the original purchaser (the “warranty period”) that the new Crown product is free of defects in materials and workmanship, and we further warrant the new Crown product regardless of the reason for failure, except as excluded in this Crown Warranty.
1 Note: If your unit bears the name “Amcron,” please substitute it for the name “Crown” in this warranty.

ITEMS EXCLUDED FROM THIS CROWN WARRANTY
This Crown Warranty is in effect only for failure of a new Crown product which occurred within the Warranty Period. It does not cover any product which has been damaged because of any intentional misuse, accident, negligence, or loss which is covered under any of your insurance contracts. This Crown Warranty also does not extend to the new Crown product if the serial number has been defaced, altered, or removed.

WHAT THE WARRANTOR WILL DO
We will remedy any defect, regardless of the reason for failure (except as excluded), by repair, replacement, or refund. We may not elect refund unless you agree, or unless we are unable to provide replacement, and repair is not practical or cannot be timely made. If a refund is elected, then you must make the defective or malfunctioning product available to us free and clear of all liens or other encumbrances. The refund will be equal to the actual purchase price, not including interest, insurance, closing costs, and other finance charges less a reasonable depreciation on the product from the date of original purchase. Warranty work can only be performed at our authorized service centers. We will remedy the defect and ship the product from the service center within a reasonable time after receipt of the defective product at our authorized service center. All expenses in remedying the defect, including surface shipping costs to the nearest authorized service center, will be borne by us. (You must bear the expense of all taxes, duties and other customs fees when transporting the product.)

HOW TO OBTAIN WARRANTY SERVICE
You must notify us of your need for warranty service not later than ninety (90) days after expiration of the warranty period. All components must be shipped in a factory pack. Corrective action will be taken within a reasonable time of the date of receipt of the defective product by our authorized service center. If the repairs made by our authorized service center are not satisfactory, notify our authorized service center immediately.
DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES YOU ARE NOT ENTITLED TO RECOVER FROM US ANY INCIDENTAL DAMAGES RESULTING FROM ANY DEFECT IN THE NEW CROWN PRODUCT. THIS INCLUDES ANY DAMAGE TO ANOTHER PRODUCT OR PRODUCTS RESULTING FROM SUCH A DEFECT.

WARRANTY ALTERATIONS
No person has the authority to enlarge, amend, or modify this Crown Warranty. This Crown Warranty is not extended by the length of time which you are deprived of the use of the new Crown product. Repairs and replacement parts provided under the terms of this Crown Warranty shall carry only the unexpired portion of this Crown Warranty.

DESIGN CHANGES
We reserve the right to change the design of any product from time to time without notice and with no obligation to make corresponding changes in products previously manufactured.

LEGAL REMEDIES OF PURCHASER
No action to enforce this Crown Warranty shall be commenced later than ninety (90) days after expiration of the warranty period.
THIS STATEMENT OF WARRANTY SUPERSEDES ANY OTHERS CONTAINED IN THIS MANUAL FOR CROWN PRODUCTS.
Telephone: 219-294-8200. Facsimile: 219-294-8301

NORTH AMERICA

SUMMARY OF WARRANTY
The Crown Audio Division of Crown International, Inc., 1718 West Mishawaka Road, Elkhart, Indiana 46517-4095 U.S.A. warrants to you, the ORIGINAL PURCHASER and ANY SUBSEQUENT OWNER of each NEW Crown product, for a period of three (3) years from the date of purchase by the original purchaser (the “warranty period”) that the new Crown product is free of defects in materials and workmanship. We further warrant the new Crown product regardless of the reason for failure, except as excluded in this Warranty.

ITEMS EXCLUDED FROM THIS CROWN WARRANTY
This Crown Warranty is in effect only for failure of a new Crown product which occurred within the Warranty Period. It does not cover any product which has been damaged because of any intentional misuse, accident, negligence, or loss which is covered under any of your insurance contracts. This Crown Warranty also does not extend to the new Crown product if the serial number has been defaced, altered, or removed.

WHAT THE WARRANTOR WILL DO
We will remedy any defect, regardless of the reason for failure (except as excluded), by repair, replacement, or refund. We may not elect refund unless you agree, or unless we are unable to provide replacement, and repair is not practical or cannot be timely made. If a refund is elected, then you must make the defective or malfunctioning product available to us free and clear of all liens or other encumbrances. The refund will be equal to the actual purchase price, not including interest, insurance, closing costs, and other finance charges less a reasonable depreciation on the product from the date of original purchase. Warranty work can only be performed at our authorized service centers or at the factory. We will remedy the defect and ship the product from the service center or our factory within a reasonable time after receipt of the defective product at our authorized service center or our factory. All expenses in remedying the defect, including surface shipping costs in the United States, will be borne by us. (You must bear the expense of shipping the product between any foreign country and the port of entry in the United States and all taxes, duties, and other customs fees for such foreign shipments.)

HOW TO OBTAIN WARRANTY SERVICE
You must notify us of your need for warranty service not later than ninety (90) days after expiration of the warranty period. All components must be shipped in a factory pack, which, if needed, may be obtained from us free of charge. Corrective action will be taken within a reasonable time of the date of receipt of the defective product by us or our authorized service center. If the repairs made by us or our authorized service center are not satisfactory, notify us or our authorized service center immediately.
DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES YOU ARE NOT ENTITLED TO RECOVER FROM US ANY INCIDENTAL DAMAGES RESULTING FROM ANY DEFECT IN THE NEW CROWN PRODUCT. THIS INCLUDES ANY DAMAGE TO ANOTHER PRODUCT OR PRODUCTS RESULTING FROM SUCH A DEFECT. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATIONS OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION OR EXCLUSION MAY NOT APPLY TO YOU.

WARRANTY ALTERATIONS
No person has the authority to enlarge, amend, or modify this Crown Warranty. This Crown Warranty is not extended by the length of time which you are deprived of the use of the new Crown product. Repairs and replacement parts provided under the terms of this Crown Warranty shall carry only the unexpired portion of this Crown Warranty.

DESIGN CHANGES
We reserve the right to change the design of any product from time to time without notice and with no obligation to make corresponding changes in products previously manufactured.

LEGAL REMEDIES OF PURCHASER
THIS CROWN WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, YOU MAY ALSO HAVE OTHER RIGHTS WHICH VARY FROM STATE TO STATE. No action to enforce this Crown Warranty shall be commenced later than ninety (90) days after expiration of the warranty period.
THIS STATEMENT OF WARRANTY SUPERSEDES ANY OTHERS CONTAINED IN THIS MANUAL FOR CROWN PRODUCTS. Telephone: 219-294-8200. Facsimile: 219-294-8301

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 mainte- nance. If you need special assistance beyond the scope of this manual, please contact our Technical Support Group.
Crown Audio Division Technical Support Group
Plant 2 SW, 1718 W. Mishawaka Rd., Elkhart, Indiana 46517 U.S.A.
Phone: 800-342-6939 (North America, Puerto Rico and Virgin Islands) or 219-294-8200
Fax: 219-294-8301 Fax Back: 800-294-4094 (North America only) or 219-293-9200
Internet: http://www.crownintl.com

IMPORTANT
THE POWER BASE-3 REQUIRES CLASS 1 OUTPUT WIRING. THE POWER BASE-1 AND 2 REQUIRE CLASS 2 OUTPUT WIRING.

CAUTION
RISK OF ELECTRIC SHOCK DO NOT OPEN
TO PREVENT ELECTRIC SHOCK DO NOT REMOVE TOP OR BOTTOM COVERS. NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL. DISCONNECT POWER CORD BE-FORE REMOVING BACK PANEL COVER TO ACCESS GAIN SWITCH.

WARNING
TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE!

Magnetic Field
CAUTION! Do not locate sensitive high-gain equipment such as preamplifiers or tape decks directly above or below the unit. Because this amplifier has a high power density, it has a strong magnetic field which can induce hum into unshielded devices that are located nearby. The field is strongest just above and below the unit.
If an equipment rack is used, we recommend locating the amplifier(s) in the bottom of the rack and the preamplifier or other sensitive equipment at the top.
The lightning bolt triangle is used to alert the user to the risk of electric shock.
The exclamation point triangle is used to alert the user to important operating or maintenance instructions.

Fig. 1.1 Power Base Front and Back Panels

Welcome

Congratulations on choosing a Power Base amplifier. Power Base amplifiers are compact, professional stereo power amplifiers engineered to meet the most demanding sound reinforcement needs. They compare very favorably to more expensive amplifiers, providing uncolored sound and signal-to-noise ratios commonly associated with recording studios.
This manual will help you successfully install and use your amplifier—we strongly recommend you read all instructions, warnings and cautions. If you plan to operate in one of the two mono modes, be sure to read Section 2.2. Also for your protection, please save your bill of sale as it is your official proof of purchase.

Unpacking
Please unpack and inspect your new amplifier for any damage that may have occurred during transit. If dam-age is found, notify the transportation company immediately. Only you, the consignee, may initiate a claim with the carrier for damage resulting during shipment. Even if the unit arrived in perfect condition, as most do, save all packing materials so you will have them if you ever need to transport the unit. NEVER SHIP THE UNIT WITHOUT THE FACTORY PACK.

Features

• Rugged, professional power amplifier built for the road. Mounts in a standard 19 inch (48.3 cm) rack.
• Crown’s patented grounded bridge circuitry generates large voltage swings while avoiding electrical stress on the output stages. This results in low distortion and high reliability.
• Front panel power switch with turn-on delay for loud-speaker protection.
• Patented Output Device Emulation Protection (ODEP®) keeps the amplifier working when others would fail.
• High damping factor provides superior control over low frequency drivers for a clean, accurate low end.
• Safe with any load. Bridge-Mono and Parallel-Mono modes offer optimal load-matching performance.
• Complete protection against shorted outputs, mismatched loads, overheating, DC input/output and high-frequency overload; full internal fault protection.
• Balanced phone jack inputs with internal three-position sensitivity switch. Optional XLR or barrier block input connectors are available with the MT-XLR or MT-BB ac-cessories.
• Ground lift switch is provided to isolate the chassis ground from the phone jack input ground.
• Efficient heat sinks and self-contained forced air cooling system dissipate heat quickly and evenly for extra amplifier protection and greater power output.
• Three year “No-Fault” full warranty and guaranteed specifications protect your investment.

Installation

Always remove power from the unit and turn the level controls off (fully counterclockwise) when making or breaking connections. This reduces the chance of blasts that can cause loudspeaker damage.
The guidelines below are provided to help you quickly get your amplifier installed and ready to go. Be sure to follow the instructions in Sections 2.1 and 2.2 for the selected mode of operation. Additional information on input sensitivity, load protection and required AC mains is provided in Sections 2.3, 2.4 and 2.5.

1. Install the amplifier in a standard 19 inch (48.3 cm) rack or place it on a stable surface. The mounting dimensions are 19 inches (48.3 cm) wide, 3.5 inches (8.9 cm) tall and 16 inches (40.6 cm) deep behind the mounting sur-face. IMPORTANT! Allow for adequate ventilation.
   Fig. 2.2 Do NOT Block Air Flow

2. Use high-quality loudspeaker cables to connect the load to the amplifier’s outputs. Do not use shielded cable.

3. Use shielded cables to connect audio sources to the amplifier inputs. Either balanced or unbalanced wiring can be used as shown below. (XLR connectors are avail-able with the MT-XLR accessory. See Section 5.)
   Fig. 2.3 Power Base Input Wiring

Stereo

1. Turn down the level controls (fully counterclockwise) and turn off the amplifier.
2. Set the back panel stereo/mono switch to Stereo.
3. If present, remove the Parallel-Mono jumper.
4. Connect the input and output cables as shown in the first example in Figure 2.1.
5. Turn on the amplifier and adjust the level for each channel using the back panel level controls.

CAUTION: Never parallel the two outputs by directly tying them together, and never parallel them with the output of another amplifier.

Mono
Your amplifier’s mono modes provide double the power of Stereo mode in a single channel. In Bridge-Mono mode, the outputs are wired in series for twice the output voltage. In Parallel-Mono mode, the outputs are paralleled for twice the current capacity.
Bridge-Mono mode is provided for loads with an impedance greater than 4 ohms. Parallel-Mono mode should be used with loads of 4 ohms or less.

BRIDGE – MONO

1. Turn down the level controls (fully counterclockwise) and turn off the amplifier.
2. Set the back panel stereo/mono switch to Bridge-Mono.
3. If present, remove the Parallel-Mono jumper.
4. Connect the input and output cables as shown in the second example in Figure 2.1. Only use the channel 1 input.
5. Make sure the load is balanced (neither side shorted to ground) and do not use the black (–) binding posts.
6. Turn on the amplifier and adjust the level. Only use the channel 1 level control.

PARALLEL – MONO

1. Turn down the level controls (fully counterclockwise) and turn off the amplifier.
2. Set the back panel stereo/mono switch to Parallel-Mono.
3. Install a solid, 14-gauge (2 mm2) or heavier jumper wire across the two red (+) binding post outputs.
4. Connect the input and output cables as shown in the third example in Figure 2.1. Only use the channel 1 input.
5. Turn on the amplifier and adjust the level. Only use the channel 1 level control.

CAUTION: With Parallel-Mono wiring, do not switch to Stereo or Bridge- Mono mode until the output jumper wire is removed.

Input Sensitivity Adjustment
The input sensitivity switch inside the amplifier is set to 0.775 volts at the factory. It can be changed to 1.4 volts or a voltage gain of 26 dB as follows:

1. Turn off and unplug the amplifier from the AC source.
2. Remove the access cover on the back panel.
3. Locate the labeled access hole for the sensitivity switch.
4. Set the switch to the desired position.
5. Replace the access cover plate.

When set to 26 dB gain, the Power Base-1® requires a 2.0 volt input, the Power Base-2 ® requires a 2.5 volt in-put and the Power Base-3 ™ requires a 3.2 volt input to deliver full output into an 8 ohm load.

Fig. 2.4 Input Sensitivity Switch

Additional Load Protection
To protect against excessive power, a fuse can be added in series with each loudspeaker cable. A single fuse can protect the entire system, or one can be used for each driver. High-frequency drivers (tweeters) are usually more sensitive to large voltage peaks, while low-frequency drivers (woofers) are typically most sensitive to the heat from average (RMS) output power. To protect your tweeters, we recommend that you use a high-speed instrument fuse like the Littlefuse 361000 series. To protect your woofers, we recommend using a slow-blow fuse that more closely represents the thermal response of your woofer. Use Figure 2.5 to find the correct value for either type of fuse.
Example: (A) Find the peak music power of your loudspeaker (such as 75 watts). (B) Find the loudspeaker impedance (8 ohms). (C) Draw a line between points A and B. The line inter-sects the middle scale at the correct fuse value (1.5 amps).

Fig. 2.5 Loudspeaker Fuse Nomograph

Required AC Mains
All Power Base amplifiers are shipped with an appropriate line cord and plug. When possible, use a power receptacle on a dedicated circuit, and always make sure it will provide the right voltage and sufficient cur-rent. We do not recommend operating your amplifier with voltages greater than 10% above or below the unit’s rated voltage. For example, if your amplifier is rated for 120 VAC, the line voltage should not exceed 132 VAC.

Operation

Precautions
Although your amplifier is protected from external faults, the following safety precautions are recommended:

1. There are important differences among the Stereo, Bridge-Mono and Parallel-Mono operating modes. Please refer to Sections 2 for additional information.
2. WARNING: Do not change the position of the stereo/mono switch unless the amplifier is first turned off.
3. CAUTION: In Parallel-Mono mode, a jumper is used to connect the red binding post outputs. Be sure to remove this jumper for Bridge-Mono or Stereo mode, or high distortion and excessive heating will occur. Also, make sure the stereo/mono switch is set to the proper position.
4. Use care when making connections, selecting sig-nal sources and controlling the output level. The load you save may be your own!
5. Do not short the ground lead of an output cable to the input signal ground. This will form a ground loop and may cause oscillations.
6. Operate the amplifier from AC mains of not more than 10% variation above or below the selected line voltage and only at the specified line frequency.
7. Never connect the output to a power supply out-put, battery or power main. Such connections may result in electrical shock.
8. Tampering with the circuitry by unqualified person-nel or making unauthorized circuit changes may be hazardous and invalidates all agency listings.

Remember: Crown is not liable for any damage that re-sults from overdriving other system components.

Power Indicator
When lit, the amber power indicator (to the left of the power switch) shows that the amplifier has been turned on. It is driven only by the low-voltage power supply and does not indicate the status of the high-voltage supplies.

Protection Systems
Power Base amplifiers have extensive protection systems, including ODEP, ultrasonic/RF protection, drive protection, transformer thermal protection and fuses or circuit breakers that protect the power supplies.

ODEP
Crown invented ODEP to keep the amplifier working under demanding conditions and to increase output efficiency. To do this, Crown established a rigorous pro-gram to measure each transistor’s safe operating area (SOA). Intelligent circuitry was then designed to simulate the instantaneous conditions of the output transistors. Its name describes what it does: Output Device Emulation Protection, or ODEP. In simple terms, ODEP compares transistor conditions to their known SOA. If more power will be asked of them than they can deliver under the existing conditions, ODEP limits the drive until conditions fall within the SOA. Limiting is proportional and kept to an absolute minimum—only what is required to prevent output transistor damage. Under normal conditions, no limiting is required and ODEP is transparent to the audio signal.
ODEP makes possible a quantum leap in output efficiency and reliability—with ODEP, the show goes on.

Ultrasonic and Radio Frequency Protection
An amplifier’s slew rate only needs to be large enough to deliver the maximum voltage at the highest required frequency. Higher slew rates actually allow undesirable ultrasonic and radio frequencies to be reproduced. By design, Power Base amplifiers have a controlled slew rate to limit the highest frequencies that they reproduce. Limiting occurs well above 20 kHz so there is no audible effect on performance. This approach protects the amplifier from radio frequencies and can even protect some sensitive loads (including some tweeters).

Drive Protection
The drive protection system temporarily removes output drive to protect the amplifier and its loads. Drive protection can be activated in two situations. First, if dangerous subsonic frequencies or direct current (DC) is detected in the amplifier’s output, the unit will activate its DC/low-frequency protection circuitry which puts the amplifier in drive protection mode. This protects the loads and pre-vents oscillations. The unit resumes normal operation as soon as the amplifier no longer detects dangerous out-put. Although it is extremely unlikely that you will ever activate the amplifier’s DC/low frequency protection system, improper source materials like subsonic square waves or input overloads that excessively clip the input signal can activate this system.
The amplifier’s fault protection system will put the amplifier in drive protection mode in rare situations where heavy common-mode current is detected in the output.
The unit should never output heavy common-mode cur-rent unless its circuitry is damaged. Activating drive protection helps prevent further damage.

Transformer Thermal Protection
All Power Base amplifiers have transformer thermal protection. This protection circuitry is activated in un-usual situations where the unit’s transformer tempera-ture rises to unsafe levels. Under these abnormal conditions, the unit removes power to the high-voltage transformer. The fan will continue to run in all units ex-cept those with 220/240 VAC transformers. The ampli-fier will return to normal after it cools to a safe temperature.
It is very unlikely that your Power Base amplifier will ever activate transformer thermal protection as long as it is operated within rated conditions. Your amplifier is designed to continue operating under conditions where other amplifiers would fail. But even when you exceed the limits of a Power Base amplifier, it still protects itself—and your investment—from damage.

Fuses and Circuit Breakers
All 120 VAC, 60 Hz units and all Power Base-3 units have a fuse that protects the low-voltage power supply and cooling fan. The Power Base-1 and Power Base-2 high-voltage power supplies are protected by fuses, while the Power Base-3 high-voltage power supplies are protected by a circuit breaker. With rated loads and output levels, these fuses (or the circuit breaker) should only shut down the amplifier in the incredibly rare instance of a catastrophic amplifier failure. The ODEP protection system keeps the amplifier opera-tional under most other severe conditions. The fuses (or breaker) can also shut down the amplifier in situations where extremely low-impedance loads and high output levels result in excessive current draw.
A Power Base amplifier will not blow its fuses or trip its breaker unless something is wrong. In the rare event that an internal fuse blows, please refer the unit to a qualified technician. If the breaker in a Power Base-3 trips, try to identify and correct the problem before re-setting it with the back panel Circuit Breaker Reset. If the problem persists, refer the unit to a qualified technician.

Controls
The Power switch is th only control located on the front panel. All others are located on the rear, including the level controls.
When making any setup or wiring changes, don’t forget to turn off the amplifier, turn down the level controls and disconnect the power cord. Be sure to turn down (full counterclockwise) the channel 2 level control when using either mono mode. The Parallell Mono/Stereo/Bridge Mono switch is used to select Stereo, Bridge-Mono or Parallel-Mono operating modes. The Input Ground Lift switch isolates the phone jack input grounds from the chassis ground to help prevent ground loops. It does not affect any installed input accessories. The Input Sensitivity Switch, located inside the back cover plate, sets the amplifier’s input sensitivity (refer to subsection 2.3 for information on changing this switch). And the Power Base-3 has a back panel Circuit Breaker Reset button that resets the circuit breaker (refer to subsection 3.3.5).

Fig. 3.1 Back Panel Level Controls

Filter Cleaning
A dust filter is provided on the unit’s air intake. If it be-comes clogged, the unit will cool less efficiently and may produce lower output levels. To clean the filter, use a Philips screwdriver to remove the three screws the secure the front grille. Use mild dishwashing deter-gent and warm water for best cleaning results. Be sure the filter is dry before you reinstall it. Replacement filters may be ordered from the factory.
Dust filters are not 100% efficient—long term this may require internal heat- sink cleaning by a qualified technician. Internal cleaning information is available from our Technical Support Group.

Specifications

All specifications apply to units in Stereo mode with 8-ohm loads and an input sensitivity of 26 dB unless otherwise specified.
Standard 1 kHz Power: refers to maximum average power in watts at 1 kHz with 0.1% THD+noise.
Full Bandwidth Power: refers to maximum average power in watts from 20 Hz to 20 kHz with 0.1% THD+noise.
120 VAC, 60 Hz Units: refers to amplifiers with dedicated trans-formers for 120 VAC, 60 Hz power mains.

Performance

• Frequency Response: ±0.1 dB from 20 Hz to 20 kHz at 1 watt.
• Phase Response: ±10 degrees from 10 Hz to 20 kHz at 1 watt.
• Signal-to-Noise: A-weighted, better than 105 dB be-low full bandwidth power. Better than 100 dB below full bandwidth power from 20 Hz to 20 kHz.
• Total Harmonic Distortion (THD): Less than 0.05%at full bandwidth power from 20 Hz to 1 kHz increas-ing linearly to 0.1% at 20 kHz.
• Intermodulation Distortion (IMD): (60 Hz and 7 kHz 4:1) Less than 0.05% from less than 158 milliwatts to full bandwidth power.
• Damping Factor: Greater than 1,000 from 10 Hz to 400 Hz.

Crosstalk

• Power Base-1: Greater than 75 dB below full band-width power from 50 Hz to 2 kHz, rising linearly to greater than 60 dB at 20 kHz.
• Power Base-2 : Greater than 90 dB below full band-width power from 50 Hz to 2 kHz, rising linearly to greater than 66 dB at 20 kHz.
• Power Base-3 : Greater than 90 dB below full band-width power from 50 Hz to 4 kHz, rising linearly to greater than 70 dB at 20 kHz.

Better than 70 dB below rated full bandwidth power from 20 Hz to 1 kHz falling linearly to better than 50 dB at 20 kHz.

• Controlled Slew Rate: Greater than 13 volts/ms.
• Voltage Gain: 20:1 ±3% or 26 dB ±0.25 dB at the maxi-mum level setting (Input Sensitivity switch set to its 26 dB position).
• Power Base-1: 51:1 ±12% or 34.3 dB ±1 dB at 0.775 volt sensitivity; 28:1 ±12% or 29.1 dB ±1 dB at 1.4 volt sensitivity.
• Power Base-2 : 64:1 ±12% or 36.2 dB ±1 dB at 0.775 volt sensitivity; 35:1 ±12% or 31.0 dB ±1 dB at 1.4 volt sensitivity.
• Power Base-3: 83:1 ±12% or 38.4 dB ±1 dB at 0.775 volt sensitivity; 46:1 ±12% or 33.3 dB ±1 dB at 1.4 volt sensitivity.

Power
Output Power: The following specifications are guaran-teed minimums for standard 1 kHz power. For more infor-mation, see the power matrices in Figures 4.1 through 4.6 (maximum average power @ 0.1% THD + N).

Power Base-1

• Stereo mode (both channels driven):
  • 240 watts into 4 ohms.
  • 200 watts into 8 ohms.
• Bridge-Mono mode:
  • 455 watts into 8 ohms.
  • 395 watts into 16 ohms.
• Parallel-Mono mode:
  • 455 watts into 2 ohms.
  • 400 watts into 4 ohms.

Power Base-2

• Stereo mode (both channels driven):
  • 460 watts into 4 ohms.
  • 325 watts into 8 ohms.
• Bridge-Mono mode:
  • 910 watts into 8 ohms.
  • 660 watts into 16 ohms.
• Parallel-Mono mode:
  • 920 watts into 2 ohms.
  • 655 watts into 4 ohms.

Power Base-3

• Stereo mode (both channels driven):
  • 760 watts into 4 ohms.
  • 540 watts into 8 ohms.
• Bridge-Mono mode:
  • 1525 watts into 8 ohms.
  • 1090 watts into 16 ohms.
• Parallel-Mono mode:
  • 1530 watts into 2 ohms.
  • 1080 watts into 4 ohms.

Load Impedance: Safe with all types of loads. Rated for 4 to 8 ohms in Stereo, 8 to 16 ohms in Bridge-Mono and 2 to 4 ohms in Parallel-Mono mode.
Required AC Mains: Current, frequency and voltage requirements are provided on each unit’s back panel. All models draw 90 watts or less at idle.

• Power Base-1: Draws up to 6 amps of current.
• Power Base-2 : Draws up to 10 amps of current.
• Power Base-3 : Draws up to 15 amps of current.

Low-Voltage Power Supply: A ±24 VDC fanformer supply (fan motor winding) regulated to ±15 VDC.
AC Connector: An appropriate AC line cord and plug are provided. 120 VAC, 60 Hz units have a standard 3-wire, 15-amp grounded connector (NEMA 5-15P).

Controls

• Power: A front panel rocker switch used to turn the amplifier on and off.
• Level: A back panel rotary potentiometer for each channel used to control the output level.
• Stereo/Mono: A three-position back panel switch used to select Stereo, Bridge-Mono or Parallel-Mono mode.
• Sensitivity: A three-position switch inside the back cover plate used to select the input sensitivity for both channels: 0.775 volts or 1.4 volts for standard 1 kHz power, or 26 dB voltage gain (see Section 2.3).
• Input Ground Lift: A two-position back panel switch used to isolate the phone jack and chassis grounds.
• Reset (Power Base-3 only): A back panel push but-ton used to reset the circuit breaker that protects the power supplies.

Indicators

• Power: This amber indicator shows the on/off status of the low voltage power supply.

Input/ Output

• Input Connector: Balanced ¼ inch phone jacks. See Section 5 for XLR and barrier block accessories.
• Input Impedance: Nominally 20 K ohms, balanced; 10 K ohms, unbalanced.
• Output Connector: Two sets of color-coded 5-way binding posts (for banana plugs, spade lugs or bare wire).
• Output Impedance: Less than 10 milliohms in series with less than 2 microhenries.
• DC Output Offset: Less than 10 millivolts.

Output Signal

• Stereo: Unbalanced, two-channel.
• Bridge-Mono: Balanced, single-channel. Channel 1 controls are active; Channel 2 controls should be turned down and not used.
• Parallel-Mono: Unbalanced, single-channel. Channel 1 controls are active; Channel 2 controls should be turned down and not used.

Protection
Power Base amplifiers are protected against shorted, open or mismatched loads; overloaded power supplies; excessive temperature, chain destruction phenomena, input overload and high-frequency blowups. They also protect loudspeakers from input and output DC, as well as providing protection from turn-on/turn-off transients.
If operating conditions are unreasonable, the patented ODEP circuitry proportionally limits the drive level to protect the output transistors, particularly in the case of elevated temperature. A thermal switch imbedded in the transformer protects the power supplies from overload. In the rare event that a transformer overheats, the thermal switch removes power, waits until the unit has cooled to a safe temperature and then resets itself.
Turn On: Four second delay with no dangerous transients. Contact us if you need to change the delay.

Construction
Durable black finish on steel chassis with special “flow-through” ventilation from front to side panels.

• Cooling: Internal heat sinks with forced-air cooling for rapid, uniform heat dissipation.
• Dimensions: Standard 19-inch (48.3 cm) rack mount width (EIA RS-310-B), 3.5-inch (8.9 cm) height and 16-inch (40.6 cm) depth behind the mounting surface.
• Approximate Weight: Center of gravity is 6 inches (15.2 cm) behind front mounting surface.

120 VAC, 60 Hz Units:

• Power Base-1: 30 pounds (13.6 kg) net; 34 pounds (15.4 kg) shipping weight.
• Power Base-2: 34 pounds (15.4 kg) net; 38 pounds (17.2 kg) shipping weight.
• Power Base-3: 36 pounds (16.3 kg) net; 40 pounds (18.2 kg) shipping weight.

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 Power Specifications
Crown’s minimum power specifications represent the absolute smallest amount of output power you can expect from your amplifier when it is driven to full output under the given conditions. Some spaces in each matrix may be left blank because the same guarantee is not provided for those conditions—however, your amplifier will perform well under all conditions listed in each matrix.
When measuring power, 0.1% THD appears to be the industry standard for distortion. Two of the maximum average power specifications shown in each minimum power matrix are measured at 0.1% THD so you can easily compare Crown specifications to those of other manufacturers. But this high level of distortion actually allows for some clipping which is undesirable. Because of this, a maximum average power spec at 0.05% THD is included in each minimum power matrix which represents non-clipped conditions. Although most manufacturers do not give you power specifications at 0.05% THD, we encourage them to provide these specifications so you will have a more realistic representation of the way amplifiers should be used in the real world—without a clipped output signal.
Many manufacturers publish power specs with a tolerance of ±1 dB or worse. This means their amplifier can deviate more than 20% in output! A 100 watt amplifier would meet their specification if it only produced 79.4 watts. Other manufacturers qualify their specs by saying they are “typical,” “subject to manufacturing tolerances,” “single channel driven” or that they are specified with “fuses bypassed.” Each of these statements effectively removes any performance guarantee. In fact, some manufacturers use these tactics to generate large power numbers, and they don’t even print a disclaimer. We take a different approach at Crown—our amplifiers are guaranteed to meet or exceed their specifications for three years. Further, because our published specs are set below our “in-house” measurements, you can expect every Crown amplifier to exceed its published minimum power specs. We believe you should get what you pay for.

Minimum Power Notes:
All minimum power specifications are based on 0.1% regulated AC mains and an ambient room temperature of 70° F (21° C). A 100V, 50Hz model was used because of its higher current demand. The standard EIA power measurement (RS-490) is not identified here because it is identical to the FTC Continuous Average Power specification.

1. A 1 kHz sine wave is presented to the amplifier and the output monitored for nonlinear distortion. The level is increased until the THD reaches 0.1%. At this level the average power per channel is reported.
2.  A sine wave is presented to the amplifier over the range from 20 Hz to 20 kHz and the output monitored for nonlinear distortion. The level at each frequency is increased until the THD reaches 0.1%. At this level the average power per channel is reported.
3.  A 1 kHz sine wave is presented to the amplifier and the output monitored for nonlinear distortion. The level is increased until the THD reaches 0.05%. At this level the average power per channel is reported.
4. Continuous power in the context of Federal Trade Commission testing is understood to be a minimum of five minutes of operation. Harmonic distortion is measured as the RMS sum total and given as a percentage of the fundamental output voltage. This applies for all wattages greater than 0.25 watts.

Power Base-1 – Minimum Guaranteed Power (Watts)

AC Mains|

Stereo-Mono Mode

| Load (Ohms)| Maximum Average| FTC Continuous Average

0.1% THD + Noise (See note 4)

0.1% THD+N

(See note 1)

| 0.1% THD+N

(See note 2)

| 0.05% THD+N

(See note 3)

1 kHz| 20Hz-20kHz| 1 kHz| 1 kHz| 20Hz-20kHz
120 VAC, 60 Hz Units| Stereo

(both channels driven)

| 4| 240| 175| 235| |
8| 200| 185| 200| 200| 180
Bridge- Mono

(balanced output)

| 8| 455| 360| 455| |
16| 395| 370| 390| 390| 350

Parallel- Mono

| 2| 455| | 445| |
4| 400| | 395| 390|
International Units| Stereo

(both channels driven)

| 4| 230| 165| 225| |
8| 205| 185| 200| 200| 175
Bridge- Mono

(balanced output)

| 8| 465| 355| 455| |
16| 410| 375| 405| 390| 350
Parallel- Mono| 2| 440| | 430| |
4| 410| | 405| 390|

Fig. 4.1 Power Base-1 Minimum Power Matrix

Power Base-2 – Minimum Guaranteed Power (Watts)

AC Mains| __

Stereo-Mono Mode

| Load (Ohms)| Maximum Average| FTC Continuous Average

0.1% THD + Noise (See note 4)

0.1% THD+N

(See note 1)

| 0.1% THD+N

(See note 2)

| 0.05% THD+N

(See note 3)

1 kHz| 20Hz-20kHz| 1 kHz| 1 kHz| 20Hz-20kHz
120 VAC, 60 Hz Units| Stereo

(both channels driven)

| 4| 460| 425| 460| 385|
8| 325| 310| 325| 310| 265
Bridge- Mono

(balanced output)

| 8| 910| 830| 905| 815|
16| 660| 615| 655| 625| 530
__

Parallel- Mono

| 2| 920| | 915| 805|
4| 655| | 650| 630|
International Units| Stereo

(both channels driven)

| 4| 425| 390| 425| 395| 325
8| 310| 290| 305| 305| 275
Bridge- Mono

(balanced output)

| 8| 855| 775| 850| 790| 640
16| 620| 575| 615| 615| 545
Parallel- Mono| 2| 850| | 845| 785|
4| 620| | 615| 610|

Fig. 4.2 Power Base-2 Minimum Power Matrix

Power Base-3 – Minimum Guaranteed Power (Watts)

AC Mains| __

Stereo-Mono Mode

| Load (Ohms)| Maximum Average| FTC Continuous Average

0.1% THD + Noise (See note 4)

0.1% THD+N

(See note 1)

| 0.1% THD+N

(See note 2)

| 0.05% THD+N

(See note 3)

1 kHz| 20Hz-20kHz| 1 kHz| 1 kHz| 20Hz-20kHz
120 VAC, 60 Hz Units| Stereo

(both channels driven)

| 4| 760| 715| 755| |
8| 540| 525| 540| 530| 495
Bridge- Mono

(balanced output)

| 8| 1525| 1430| 1500| |
16| 1090| 1045| 1075| 1055| 985
__

Parallel- Mono

| 2| 1530| | 1520| |
4| 1080| | 1080| 1065|
International Units| Stereo

(both channels driven)

| 4| 680| 630| 660| 555| 485
8| 510| 495| 505| 510| 470
Bridge- Mono

(balanced output)

| 8| 1335| 1240| 1305| 1115| 1085
16| 1025| 980| 1000| 1025| 930
Parallel- Mono| 2| 1365| | 1340| 1115|
4| 1015| | 1010| 1030|

Fig. 4.3 Power Base-3 Minimum Power Matrix

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. Burst signals act like large transient peaks that are present in common source signals. Loudspeakers can respond to a single cycle burst, so the single cycle burst specifications should be used to help you protect your loudspeakers. In contrast, a 40 millisecond burst represents the typical response time of the human ear. Your ear will not respond to the entire dynamic change of a burst that lasts less than 40 milliseconds.
The specifications are provided at 0.05% THD because this represents a low distortion condition. To help you operate your amplifier within these tolerances, Crown’s premium amplifiers include an input/output comparator that shows when the amplifier has exceeded 0.05% THD. Operating the amplifier at levels higher than 0.05% THD can result in output power levels that are higher than those listed in the maximum power matrices.
Maximum Power Notes:
All maximum power specifications are based on 0.1% regulated AC mains and an ambient room temperature of 70° F (21° C). A 100V, 50Hz model was used because of its higher current demand. Although it is an unusual condition, your amplifier can function well with AC mains voltages up to 10% over the specified line voltage. With overvoltage conditions, your amplifier may be capable of delivering instantaneous power levels up to 20% greater than the specifications in the matrix.

1. A single cycle sine wave is presented to the amplifier and monitored for nonlinear distortion. The average power during the burst is reported. Loudspeakers must be able to withstand this level if they are to be safely used with this amplifier.
2. A 40 millisecond sine wave burst (10 percent duty cycle) is presented to the amplifier and monitored for nonlinear distortion. The average power during the burst is reported. This power level is a measurement of the amplifier’s maximum transient power that can be perceived by the human ear.

Power Base-1 – Maximum Power (Watts)

AC Mains|

Stereo-Mono Mode

| Load (Ohms)| Single Cycle Tone Burst At less than 0.05% THD (See note 1)| 40 Millisecond Tone Burst

0.05% THD + Noise

(See note 2)

50 Hz| 1 kHz| 7 kHz| 50 Hz| 1 kHz| 7 kHz
120 VAC, 60 Hz Units| Stereo

(both channels driven)

| 4| 325| 335| 335| 315| 295| 310
8| 265| 310| 300| 230| 220| 230
Bridge- Mono

(balanced output)

| 8| 630| 640| 620| 600| 565| 580
16| 540| 630| 610| 470| 440| 455
Parallel- Mono| 2| 635| 645| 640| 620| 580| 605
4| 530| 615| 600| 465| 430| 450
International Units| Stereo

(both channels driven)

| 4| 325| 330| 330| 320| 315| 330
8| 290| 345| 335| 260| 235| 250
Bridge- Mono

(balanced output)

| 8| 640| 650| 670| 635| 625| 655
16| 580| 690| 670| 520| 470| 495

Parallel- Mono

| 2| 620| 625| 625| 615| 615| 625
4| 580| 690| 670| 515| 475| 490

Fig. 4.4 Power Base-1 Maximum Power Matrix

Power Base-2 – Maximum Power (Watts)

AC Mains| __

Stereo-Mono Mode

| Load (Ohms)| Single Cycle Tone Burst At less than 0.05% THD (See note 1)| 40 Millisecond Tone Burst

0.05% THD + Noise

(See note 2)

50 Hz| 1 kHz| 7 kHz| 50 Hz| 1 kHz| 7 kHz
120 VAC, 60 Hz Units| Stereo

(both channels driven)

| 4| 655| 805| 790| 550| 500| 520
8| 460| 525| 515| 400| 375| 395
Bridge- Mono

(balanced output)

| 8| 1410| 1850| 1805| 1190| 1090| 1125
16| 915| 1060| 1020| 795| 755| 780
Parallel- Mono| 2| 1440| 1685| 1645| 1185| 1085| 1120
4| 915| 1055| 1020| 805| 750| 775
International Units| Stereo

(both channels driven)

| 4| 720| 900| 885| 605| 545| 565
8| 465| 530| 510| 410| 380| 395
Bridge- Mono

(balanced output)

| 8| 1440| 1770| 1785| 1200| 1075| 1120
16| 920| 1055| 1020| 820| 750| 785
__

Parallel- Mono

| 2| 1390| 1670| 1655| 1185| 1065| 1110
4| 915| 1055| 1015| 820| 750| 775

Fig. 4.5 Power Base-2 Maximum Power Matrix

Power Base-3 – Maximum Power (Watts)

AC Mains|

Stereo-Mono Mode

| Load (Ohms)| Single Cycle Tone Burst At less than 0.05% THD (See note 1)| 40 Millisecond Tone Burst

0.05% THD + Noise

(See note 2)

50 Hz| 1 kHz| 7 kHz| 50 Hz| 1 kHz| 7 kHz
120 VAC, 60 Hz Units| Stereo

(both channels driven)

| 4| 1090| 1575| 1525| 910| 815| 855
8| 715| 870| 838| 610| 570| 595
Bridge-Mono

(balanced output)

| 8| 2155| 3140| 3040| 1780| 1615| 1690
16| 1415| 1740| 1675| 1250| 1135| 1180
Parallel-Mono| 2| 2140| 3135| 3015| 1790| 1605| 1680
4| 1420| 1735| 1665| 1225| 1135| 1170
International Units| Stereo

(both channels driven)

| 4| 1190| 1750| 1695| 970| 870| 920
8| 785| 960| 920| 675| 625| 645
Bridge-Mono

(balanced output)

| 8| 2355| 3490| 3380| 1945| 1725| 1805
16| 1540| 1915| 1840| 1360| 1235| 1285

Parallel-Mono

| 2| 2330| 3485| 3345| 1940| 1720| 1800
4| 1570| 1895| 1825| 1360| 1235| 1270

Fig. 4.6 Power Base-3 Maximum Power Matrix

Accessories

There are two accessories available at the time of this printing: the MT-XLR and the MT-BB. Important: The MT-XLR and MT-BB must be installed at a Crown Factory Service Center or the Crown factory.

5.1 MT-XLR
The MT-XLR is an accessory panel that provides two standard 3-pin female XLR input connectors. The MT-XLR accessory makes it easy to quickly change connections in a system that uses standard XLR connectors. It can also be used in systems that need to daisy chain an input signal from one amplifier to an- other. Because the MT-XLR connectors are wired in parallel with the amplifier’s built in phone jack connectors, an input signal fed to either input can be fed to another amplifier from the unused connector for that channel.

Fig. 5.1 The MT-XLR

MT-BB
The MT-BB is an accessory panel that provides barrier strip input connectors. An MT-BB accessory might be desirable in applications requiring bare wire connections. It can also be used to daisy chain an input signal from one amplifier to another just like the MT-XLR.

Fig. 5.2 The MT-BB

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 re-move covers. No user serviceable parts inside. Refer servicing to a qualified technician.

Worldwide Service
Service may be obtained from an authorized service center. (Contact your local Crown/Amcron representative or our office for a list of authorized service centers.) To obtain service, simply present the bill of sale as proof of purchase along with the defective unit to an authorized service center. They will handle the necessary paperwork and repair.
Remember to transport your unit in the original factory pack. We will pay the surface shipping costs both ways for warranty service to the authorized service center nearest you after receiving copies of all ship-ping receipts. You must bear the expense of all taxes, duties, and customs fees when transporting the unit.

North American Service
Service may be obtained in one of two ways: from an authorized service center or from the factory. You may choose either. It is important that you have your copy of the bill of sale as your proof of purchase.

Service at a North American Service Center
This method usually saves the most time and effort. Simply present your bill of sale along with the defective unit to an authorized service center to obtain service. They will handle the necessary paperwork and repair. Remember to transport the unit in the original factory pack. A list of authorized service centers in your area can be obtained from our Technical Support Group.

Factory Service
To obtain factory service, fill out the service information page that follows and send it along with your proof of purchase and the defective unit to the Crown factory. For warranty service, we will pay for ground shipping both ways in the United States after receiving copies of the shipping receipts. Shipments should be sent “UPS ground.” (If the unit is under warranty, you may send it C.O.D. for the cost of freight via UPS ground.) The factory will return it via UPS ground. Please contact us if other arrangements are required.

Factory Service Shipping Instructions:

1. When sending a Crown product to the factory for service, be sure to fill out the service information form that follows and enclose it inside your unit’s shipping pack. Do not send the service information form separately.
2. To ensure the safe transportation of your unit to the factory, ship it in an original factory packing container. If you don’t have one, call or write Crown’s Parts Department. With the exception of polyurethane or wooden crates, any other packing material will not be sufficient to withstand the stress of shipping. Do not use loose, small size packing materials.
3. Do not ship the unit in any kind of cabinet (wood or metal). Ignoring this warning may result in ex-tensive damage to the unit and the cabinet. Accessories are not needed—do not send the instruction manual, cables and other hardware.

If you have any questions, please call or write the Crown Technical Support Group.

Crown Audio Division
Technical Support / Factory Service
Plant 2 SW, 1718 W. Mishawaka Rd., Elkhart, Indiana 46517 U.S.A.
Telephone: 219-294-8200
800-342-6939 (North America,
Puerto Rico, and Virgin Islands only)
Facsimile: 219-294-8301 (Technical Support)
219-294-8124 (Factory Service)
Fax Back: 219-293-9200
800-294-4094 (North America only)
Internet:http://www.crownintl.com

Crown Factory Service Information

Shipping Address: Crown International, Inc., Factory Service, Plant 2 SW, 1718 W. Mishawaka Rd., Elkhart, IN 46517 Phone: 1-800-342-6939 or 1-219-294-8200 Fax: 1-219-294-8124

• Owner’s Name: _____
• Shipping Address: __
• Phone Number: _____
• Fax Number: _____
• Model: ____
• Serial Number: __
• Purchase Date: ___

NATURE OF PROBLEM
(Be sure to describe the conditions that existed when the problem occurred and what attempts were made to correct it.)

• Other equipment in your system: _____

If warranty has expired, payment will be: Cash/Check  VISA  MasterCard  C.O.D.

• Card Number:___
• Exp. Date:___
• Signature:____
  ENCLOSE THIS PORTION WITH THE UNIT. DO NOT MAIL SEPARATELY.

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