Crown_Power_Base_Series_Reference_Manual电路图.pdf

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1、Models: Power Base-1, 2 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 t

2、he phone jack input ground. Efficient heat sinks and self-contained forced air cool- ing 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. Fig. 1.1 Power Base Fr

3、ont and Back Panels CAUTION: THIS COVER IS NECESSARY FOR EFFICIENT COOLING OF THE AMPLIFIER. REMOVE ONLY TO ACCESS GAIN SWITCH. REG. U.S. PAT. OFF. 4,330,809 4,611,180 CAUTION: TURN OFF AMPLIFIER BEFORE CHANGING THIS SWITCH! STEREO BRIDGE MONO PARALLEL MONO BRIDGE-MONO WIRING TURN AMPLIFIER OFF. SET

4、 STEREO/MONO SWITCH TO BRIDGE-MONO. OUTPUT ACROSS RED TERMINALS ONLY. (CH-1 IS POSITIVE.) PARALLEL-MONO WIRING TURN AMPLIFIER OFF. SET STEREO/MONO SWITCH TO PARALLEL-MONO. ADD JUMPER (14 GAGE OR LARGER) ACROSS RED TERMINALS. OUTPUT ACROSS CH-1 TERMINALS ONLY. 1 2 3 4 1 2 3 CH-2CH-1 + + THIS AMPLIFIE

5、R IS EQUIPPED WITH SELECTABLE INPUT SENSITIVITY. REMOVE COVER PLATE (ABOVE) TO ACCESS SENSITIVITY SWITCH. CH-2 INPUT GROUND LIFT (AFFECTS PHONE INPUTS ONLY.)(MONO) MODEL: POWER-BASE 3 12.5 AMPS AC VOLTS: 120 60 Hz MAXIMUM OUTPUT: 700 WATTS PER CHANNEL INTO 4 OHMS AT 1 KHz WITH NO MORE THAN 0.1% THD.

6、 INPUT GAIN CH-1 INPUT GAIN CLASS 2 OUTPUT WIRING REQUIRED. OUTPUTS CAUTION: 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 BEFORE REMOVING REAR COVER PLATE TO ACCESS SENSITIVITY SW

7、ITCH. ATTENTION: DBRANCHER AVANT DOUVRIR. WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. LIFT PUSH TO RESET BALANCED INPUT WIRING + TIP RING SLEEVEGND UNBALANCED INPUT WIRING +TIP SLEEVEGND 0 1 2 3 4 567 8 9 10 11 120 1 2 3 4 567 8 9 10 11 12

8、 INTERNATIONAL, INC. ELECTRONIC EQUIPMENT ELKHART, IN 46517 MADE IN U.S.A. SERIAL NUMBER 0000 000000 P R E S S R E S E T OFF POWER Removable grille and dust filter Power Indicator Power Switch Stereo/Mono Switch Ch.1 Inch Phone Input Ch.2 Inch Phone Input Ground Lift Switch Ch.1 Level Control Ch.2 L

9、evel Control 5-Way Binding Post Output Connectors Access Cover Reset Switch (Power Base3 Only) Power Cord 1.1 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 imme- diately. Only you,

10、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. Power Base Seri

11、es Power Amplifiers Page 8 MIXER LOUDSPEAKERS + + CHANNEL 1 CHANNEL 2 CHANNEL 1 CHANNEL 2 STEREO MODE BRIDGE-MONO MODE STEREO BRIDGE MONO PARALLEL MONO PARALLEL-MONO MODE MIXER LOUDSPEAKER + ONLY USE THE CHANNEL 1 INPUT ONLY USE THE CHANNEL 1 INPUT STEREO BRIDGE MONO PARALLEL MONO MIXER LOUDSPEAKER

12、+ POWER BASE AMPLIFIER POWER BASE AMPLIFIER POWER BASE AMPLIFIER STEREO BRIDGE MONO PARALLEL MONO CAUTION: TURN OFF AMPLIFIER BEFORE CHANGING THIS SWITCH. STEREO BRIDGE MONO PARALLEL MONO CH.2 LEVEL CONTROL GROUND LIFT SWITCH CH.1 LEVEL CONTROL ADD A 14 GAUGE (OR LARGER) JUMPER BETWEEN THE RED CHANN

13、EL 1 AND CHANNEL 2 BINDING POSTS. DO NOT USE BLACK TERMINALS TURN CHANNEL 2 OFF (FULLY CCW) IN THIS MODE. CAUTION: TURN OFF AMPLIFIER BEFORE CHANGING THIS SWITCH. STEREO BRIDGE MONO PARALLEL MONO CHANNEL 2 IS NOT USED IN THIS MODE. CAUTION: TURN OFF AMPLIFIER BEFORE CHANGING THIS SWITCH. STEREO BRID

14、GE MONO PARALLEL MONO CH-2CH-1 CH-2CH-1 CH-2CH-1 CHANNEL 2 IS NOT USED IN THIS MODE. Fig. 2.1 Three System Connection Methods Power Base Series Power Amplifiers Page 9 2 Installation Always remove power from the unit and turn the level controls off (fully counterclockwise) when making or breaking co

15、nnections. 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

16、 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) de

17、ep behind the mounting sur- face. IMPORTANT! Allow for adequate ventilation. 2.1 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 ou

18、tput cables as shown in the first example in Figure 2.1. 5. Turn on the amplifier and adjust the level for each chan- nel using the back panel level controls. CAUTION: Never parallel the two outputs by di- rectly tying them together, and never parallel them with the output of another amplifier. 2.2

19、Mono Your amplifiers 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 wi

20、th an im- pedance greater than 4 ohms. Parallel-Mono mode should be used with loads of 4 ohms or less. B R I D G E - M O N O 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 Paralle

21、l-Mono jumper. 4. Connect the input and output cables as shown in the sec- ond 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 th

22、e channel 1 level control. P A R A L L E L - M O N O 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

23、. 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 ju

24、mper wire is removed. AIR FLOW AIR FLOW AMPLIFIER (TOP VIEW) RACK CABINET 16 in 40.6 cm 2 in MIN. 17 in 43.2 cm AIR FLOW IMPORTANT: Be sure the back of the amplifier is supported. + 3 1 2 GND FROM PREAMPLIFIERINPUT BALANCED + SHIELD FROM PREAMPLIFIER INPUT UNBALANCED + SHIELD + 3 1 2 SHIELD Fig. 2.3

25、 Power Base Input Wiring 2. Use high-quality loudspeaker cables to connect the load to the amplifiers 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 avai

26、l- able with the MT-XLR accessory. See Section 5.) Fig. 2.2 Do NOT Block Air Flow Power Base Series Power Amplifiers Page 10 2.3 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

27、 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

28、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. 0.77 V 26 dB SENSITIVITY SWITCH INSIDE ACCESS HOLE 1.4 V THIS AMPLIFIER IS EQUIPPED WITH SELECTABLE INPUT SENSITIVITY. REMOVE COVER PLATE

29、(ABOVE) TO ACCESS SENSITIVITY SWITCH. CH-2 INPUT GROUND LIFT (AFFECTS PHONE INPUTS ONLY.)(MONO) INPUT GAIN CH-1 INPUT GAIN LIFT BALANCED INPUT WIRING + TIP RING SLEEVEGND UNBALANCED INPUT WIRING +TIP SLEEVEGND 0 1 2 3 4 5 6 7 8 9 10 11 120 1 2 3 4 5 6 7 8 9 10 11 12 Fig. 2.4 Input Sensitivity Switch

30、 2.4 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 l

31、ow-frequency drivers (woofers) are typically most sen- sitive 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 closel

32、y represents the thermal response of your woofer. Use Figure 2.5 to find the cor- rect 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- se

33、cts the middle scale at the correct fuse value (1.5 amps). 1.0 1.2 1.4 1.6 2.5 3 4 5 6 7 8 9 10 12 14 16 20 25 30 20 15 10 8 6 5 4 3 2 1.5 1 .8 .6 .5 .4 .3 .2 .15 .1 .08 3000 2000 1500 1000 800 600 400 300 200 150 100 80 60 40 30 20 15 10 8 6 4 3 2 1.5 1 LOUDSPEAKER IMPEDANCE (ohms) FUSE (amps) LOUD

34、SPEAKER RATING PEAK MUSIC POWER (watts) (Typically 4 times the continuous average power) Answer: Fuse = 1.5 A 2 40 Example: Impedance = 8 ohms. Peak Power = 75 W Fig. 2.5 Loudspeaker Fuse Nomograph 2.5 Required AC Mains All Power Base amplifiers are shipped with an appro- priate line cord and plug.

35、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 units rated voltage. For example, if your amplifier is rated f

36、or 120 VAC, the line voltage should not exceed 132 VAC. Power Base Series Power Amplifiers Page 11 3.3.1 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 transistors

37、 safe operating area (SOA). Intelligent circuitry was then designed to simu- late the instantaneous conditions of the output transis- tors. 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 p

38、ower 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 propor- tional and kept to an absolute minimumonly what is required to prevent output transistor damage. Under normal conditions, no limiting is req

39、uired and ODEP is transparent to the audio signal. ODEP makes possible a quantum leap in output effi- ciency and reliabilitywith ODEP, the show goes on. 3.3.2 Ultrasonic and Radio Frequency Protection An amplifiers slew rate only needs to be large enough to deliver the maximum voltage at the highest

40、 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 au- dible effect on

41、 performance. This approach protects the amplifier from radio frequencies and can even pro- tect some sensitive loads (including some tweeters). 3.3.3 Drive Protection The drive protection system temporarily removes output drive to protect the amplifier and its loads. Drive protec- tion can be activ

42、ated in two situations. First, if dangerous subsonic frequencies or direct current (DC) is detected in the amplifiers 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

43、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 amplifiers DC/low frequency protection system, improper source materials like subsonic square waves or input overloads that excessively clip

44、the input signal can activate this system. The amplifiers fault protection system will put the am- plifier in drive protection mode in rare situations where heavy common-mode current is detected in the output. 3 Operation 3.1 Precautions Although your amplifier is protected from external faults, the

45、 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 tur

46、ned 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

47、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 n

48、ot 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

49、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. 3.2 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. 3.3 Protection Systems Power Base amplifiers have extensive protection sys- tems, including ODEP, ultrasonic/RF protection, d