Professional Power Amplifier User Manual
C o n t e n t s Safety Information................................................................................... 3 1.0 Introduction & Unpacking ..................................................................... 4 2.0 Mechanical Installation ........................................................................ 5 3.0 AC Power Connection .......................................................................... 6 4.0 Audio Connections .................................................................
S a f e t y Important Safety Instructions I n f o r m a t i o n DO NOT REMOVE COVERS. NO USER SERVICEABLE PARTS INSIDE. 1) Read these instructions. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL. 2) Keep these instructions. 3) Heed all warnings. 4) Follow all instructions. 5) Do not use this apparatus near water. 6) Clean only with a dry cloth. 7) Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.
1 . 0 I n t r o d u c t i o n & U n p a c k i n g Front panel Rear panel Introduction The PULSE series of amplifiers are high performance professional power amplifiers capable of delivering major power output from a new generation of switched mode power supplies. All Pulse series amplifiers are housed in the same size 2U cases and feature light, powerful switching power supplies along with massive heatsinks and two dual-speed cooling fans.
2 . 0 M e c h a n i c a l I n s t a l l a t i o n A vertical rack space of 2U (88mm high) is required, with an in rack depth of 18.1 inches (460mm). The amplifier protrudes 1.6 inches (40mm) from the rack supports. Mounting & unit dimensions If the unit is likely to undergo extreme vibration through trucking and touring, front rack ear reinforcement brackets and rear mounting plates must be fitted. These are available from your dealer.
3 . 0 A C P o w e r C o n n e c t i o n WARNING! THIS APPLIANCE MUST BE GROUNDED. The amplifier must always be connected to a 3-wire grounded AC outlet. The rack framework must also be connected to the same grounding circuit. The unit must NOT be operated unless the power cables' ground wire is properly terminated - this is important for personal safety as well as for proper control over the system grounding. The wires in the power lead are color coded as follows: Green and Yellow......Ground Blue....
4 . 0 A u d i o C o n n e c t i o n s Inputs For each channel, there is a 1/4” phone jack socket and female XLR socket provided for signal input on the rear panel of the amplifier. Each is electronically balanced at an impedance greater than 10k ohms. The phone jack and XLR connectors are internally wired in parallel, and therefore either socket may be used for the input signal. The connectors not used in this manner function as loop-through connectors for daisy chaining a number of channels.
A u d i o C o n n e c t i o n s . . . Outputs Stereo wiring Your Pulse 4x300 amplifier can be fitted with either ® binding post or Speakon connectors for each channel. Note that it is possible to lever the caps out of the ends of the binding posts to insert 4mm banana type plugs but this will invalidate the product safety approvals in some territories. The side entry positions for these connectors should therefore be used if possible.
5 . 0 C o n t r o l o p e r a t i o n a. Power Switch Pressing this switch so that the white dot is closest to the front panel signals to the microprocessor that the user wishes to turn on the power supply. Note that the microprocessor will only switch the power supply on once it has assured that there are no internal faults. From the first application of AC power it takes approximately 7 seconds to complete these tests.
6 . 0 I n d i c a t o r s A. AC Present This light glows when AC power is applied to the amplifier, whether or not the amplifier is actually running. This light will still glow even if the rear panel fuse is blown because it is powered from the separate, internally fused supply that powers the microprocessor. B. Operate Illuminated when the main power supply is switched on using the front panel switch. C. Fault If, for any reason, the microprocessor detects a problem then this light comes on.
I n d i c a t o r s . . . E. Signal This indicator lights when a signal exceeding approximately -26dBu is applied to a channel. In bridge mode only the channel 1 and/or channel 3 light operate(s). F. Clip This light is in fact rather more sophisticated than a simple clip indicator; it actually measures distortion.
7 . 0 Ty p i c a l a p p l i c a t i o n s a. Four Channel Sound Reinforcement In this example, each channel of the PULSE 4x300 is being used independently to control the sound level in all four corners of a venue. For this application, ensure that both rear panel BRIDGE switches are in the NORMAL position. More than one speaker may be used on each channel as long as the total impedance is not less that 2 ohms. See section 7e of this manual for more information about how to calculate impedance.
Ty p i c a l a p p l i c a t i o n s . . . c. Three channel operation This configuration demonstrates the flexibility of the PULSE 4x300. Channels 1+2 are bridged and drive a 600W 4 ohm sub-bass speaker. Channels 3 and 4 are used independently to drive two 300W 4 ohm midhigh speakers using an external crossover unit between the mixer and the amplifier. 1+2 bridged 1 3 4 3+4 normal L 4 1 3 R d.
Ty p i c a l a p p l i c a t i o n s . . . e. Calculating Impedance Measured in ohms, impedance is a measure of AC resistance. Loudspeakers generally come in 16, 8 or 4 ohm varieties. Amplifiers have a lower limit to what impedance they can drive without being overloaded, there is not usually an upper limit. The PULSE 4x300 can drive any impedance between an open circuit and 2 ohms when in stereo and between an open circuit and 4 ohms when bridged.
8 . 0 G l o s s a r y In this section many of the terms used throughout this manual are explained in more detail. Active Active electronic circuits are those which are capable of voltage and power gain by using transistors and integrated circuits. Amplitude Refers to the voltage level or intensity of a signal, and is usually measured in volts or decibels. Balanced A three wire connection in which two of the wires carry the signal information, the third acts as a shield tied to chassis ground.
G l o s s a r y. . . dBu or dBv The addition of a lower case ”u” or “v” after dB indicates an absolute scaling for the dB ratio. 0dBu (or 0 dBv) = 778mV or 0.778 Volts, and it has no regard for power or impedance. This term is widely used for expressing signal voltages in modern audio equipment with high input impedances and low output impedances. For dBv the same scale is used as for dBu above, except that 0dBV = 1.0 Volts.
G l o s s a r y. . . Transient A sudden burst of energy in an audio signal which only lasts for a small period of time relative to the rest of the signal. The level of these transients can often reach 10 times (+20dB) or so above the normal operating level of the audio equipment, and may cause distortion if headroom is inadequate. ® Speakon A type of connector, manufactured by Neutrik with either 2, 4 or 8 pole connectors, specifically designed for connecting speakers to amplifiers.
9 . 0 Power Ratings S p e c i f i c a t i o n s Pulse 4x300 Stereo Measured per channel, both channels driven at 1kHz to no more than 0.1% THD+N 8 ohms 170W rms 4 ohms 300W rms 2 ohms 330W rms* * Note: 2 ohm spec is at 1% THD Bridged Mono 16 ohms 400W rms 8 ohms 600W rms 4 ohms 660W rms* * Note: 4 ohm bridged spec is at 1% THD Input Sensitivity +1dBu for full output Input Impedance 20 kohm Input Connectors 1/4-inch TRS balanced phone jack and female XLR Distortion <0.
1 0 . 0 Tr o u b l e s h o o t i n g Checklist Problem: No output Check: Are the AC Present and Operate lights on? Are the Fault & Temp lights off? Are the Signal lights on? Are the level controls turned up? Are the speakers properly connected? (in particular check that older style ‘ring lock’ type Speakons are rotated in the socket).
Tr o u b l e s h o o t i n g . . . Status Indication There is a microprocessor inside each PULSE amplifier responsible for monitoring all critical systems. The status of which are displayed on the front panel lights. Their indication is as follows: Fault and both Temp lights flashing The amplifier has just been plugged in and the microprocessor is carrying out a test sequence. This is normal and will stop after about 7 seconds.
1 1 . 0 S e r v i c e Crown amplifiers are quality units that rarely require servicing. Before returning your unit for servicing, please contact Crown Technical Support to verify the need for servicing. material will not be sufficient to withstand the stress of shipping. Do not use loose, small size packing materials. This unit has very sophisticated circuitry which should only be serviced by an authorized Crown Service Center..
3 YEAR THREE YEAR FULL WARRANTY 3 YEAR UNITED STATES & CANADA WORLDWIDE EXCEPT USA & CANADA SUMMARY OF WARRANTY Crown International, 1718 West Mishawaka Road, Elkhart, Indiana 465174095 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.
Version 2.0 CB 190901 ZM10091-01 Crown part number 133783-1 Crown is a registered trademark of Crown International.
