STEREO POWER AMPLIFIER OWNER MANUAL PR-150 DESIGNED IN U.K. PDF created with FinePrint pdffactory trial version

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1 STEREO POWER AMPLIFIER OWNER MANUAL PR-150 DESIGNED IN U.K.

2 INTRODUCTION Congratulations on your purchase of MA PR-150 Stereo Power Amplifier. The performance of PR-150 is perfect for any audio application, musician, performer, studio engineer, and sound contractor. We have many years of experience in manufacturing audio products, and excellent research and development, have enable us to provide an amplifier with the highest quality and reliability. PR-150 was designed and manufactured using only the best quality of components and materials. Each amplifier design must satisfy our team of highly-trained technicians and musicians before it is approved. FEATURES 300 Watts RMS. Stereo/Mono Bridge Operation. Internal Protection Circuitry. Convection Cooled. Excellent Signal to Noise Ratio. Automatic Recovery Circuit. Aluminum front panel. Designed in UK. PLEASE READ THIS MANUAL BEFORE OPERATING THIS UNIT Caution : To prevent malfunctioning and/or possible equipment damage: Before plugging the unit into the power source: (1) the voltage switch should be set for the correct one for your area ( or ) and (2) all equipment connected to the unit outputs should be turned off or all the inputs turned down.

3 IMPORTANT SAFETY INSTRUCTIONS Read, follow, heed, and keep all instructions and warnings. Do not operate near any heat source and do not block any ventilation opening on this apparatus. For proper operation, this unit requires 3 (75cm) of will ventilated space around heatsinks and other air flow provisions in the cabinet. Do not use this apparatus near splashing, falling, spraying, or standing liquids. Clean only with lint-free damp cloth and do not use cleaning agents. Only connect power cord to a polarized, safety grounded outlet wired to current electrical cedes and compatible with voltage, power, and frequency requirements stated on the rear panel of the apparatus. Protect the power cord from damage due to being walked on, pinched, or strained. Unplug the apparatus during lightning storms or when unused for long periods of time. Only use attachment, accessories, stands, or brackets specified by the manufacturer for sage operation and to avoid injury. This apparatus does not operate normally and requires service with any physical damage from impact or any exposure to moisture. Service must be performed by qualified personnel. Our amplifiers are capable of producing high sound pressure levels. Continued exposure to high sound pressure levels can cause permanent hearing impairment or loss. User caution is advised and ear protection is recommended if unit is operated at high volume.

4 FRONT PANEL INFORMATION 1.POWER SWITCH: This switch applies AC power to the amplifier. The amp is on when the top of the switch is depressed, off when the bottom of the switch is depressed. The power LED indicator illuminates when the amplifier is on. 2.POWER LED: This LED illuminates when AC power is applied by means of the Power switch. If the LED fails to illuminate, check the AC outlet or the fuse on the rear panel. 3.PROTECT LED: This LED illuminates whenever the internal protection relay for the channel is activated. The protection relay is activated for a short period upon initial turn-on and at turn-off to prevent transient spikes from being reproduced through your speakers. A fault condition is also indicated in the event of an over temperature status, or if DC voltages are present at the output. During thermal protection, both channels are shut down until the temperature returns to a safe operating level. In the event of DC voltage on the output, only the affected channel will be disconnected. The circuitry associated with the LED indicator provides valuable protection for both the amplifier and your speakers. 4.SIGNAL LED: This LED illuminates when signal is detected at the amplifier s output terminals. The level of the signal must be at least 1% of the amplifier s full rated output to make the LED illuminate. 5.PEAK LED: The PR-150 designed an internal automatic limit circuit to prevent the amplifier from clipping. The Peak LED illuminates (indicates the limiter is active) whenever the input signal attempts to overdrive the amplifier. (Not only does clipping produce harsh sounding distortion, it is also capable of damaging speaker components particularly high frequency driver.) Periodic flashing of the Peak LED indicates operation at or near full output. This is normal. Steady illumination of the LED indicates constant operation of the Limiter, with the possibility that the input signal should be reduced by means of the Level control. The Limiter within the PR-150 is fully automatic, with no defeat switch, insuring you complete protection against clipping at all times. 6.SENSITIVITY CONTROL: These rotary potentiometers control the level or gain of each channel, with the fully clockwise position of each providing a sensitivity of +2dBv. Normal calibration of the PR-150 to a mixer would cause the Peak LED to flash at the same time that the mixer s VU meters indicate full output. 7.FRONT PANEL EXHAUST VENT: A variable speed internal cooling fan is used to draw air through the unit to keep it running even under extreme operating conditions. Air is drawn in

5 through the unit s rear and side intake vents and is forced out through the front panel exhaust vent. Keep these vents clear and free from obstruction at all times to insure proper cooling. REAR PANEL INFORMATION 50Hz, 450W 8.FAN INTAKE AREA: Air for cooling the PR-150 is drawn in by the fan at the rear and side, directed through the amplifier, and exhausted through the front panel vent. Do not block or impede the airflow through these vents and keep the area free of foreign materials. 9.STEREO / MONO BRIDGE SWITCH: Use this switch to select the operating mode of the amplifier. In the Mono Bridge mode, Channel 1 functions as the input channel and the Channel 2 inputs are disabled. 10.MIC INPUT: These XLR jacks will accept any balanced or unbalanced low impedance line level source by means of a three-pin XLR plug. The wiring for the plug is as follows: Pin 1 = Ground, Pin 2 = Signal +, Pin 3 = Signal LINE INPUT: These 1/4 jacks accept line level signal sources by means of cables fitted with standard 1/4 phone plugs. Low impedance balanced or unbalanced, as will as high impedance sources are acceptable for these inputs. Low impedance balanced inputs are to be wired as follows: Tip = Signal +, Ring = Signal -, Sleeve = Ground. NOTE: In the Mono mode, the Channel 1 input jacks are used and the Channel 2 input jacks are disabled. 12.SPEAKER OUTPUTS: These five-way binding posts offer an excellent method of connecting the amplifier to your speakers using cables terminated with spade lugs, banana plugs, or bare wire. Use of these connectors is highly recommended for high power operation. When using the amplifier in the Mono Bridge mode, use the RED terminals. (Methods of connecting are shown on Pages 7-13 of this manual.) 13.VOLTAGE SELECTOR: Use this switch to match the unit to the AC line voltage. If the switch is changed, the fuse must be changed according to the labeling on the rear of the unit.

6 14.FUSE HOLDER: The unit use an AC line fuse to help protect it from damages due to excessive current demands. If the amplifier does not function, check this fuse. If it is blown, replace it ONLY with the same size and type as indicated near the holder. If the fuse blows repeatedly, have the amplifier checked by a qualified service person. 15.AC LINE: Firmly insert the supplied AC power cord into this socket until it is fully seated. This grounded power cord is to be plugged into a grounded power outlet, wired to current electric codes and compatible with voltage, power, and frequency requirements stated on the rear panel. Do not attempt to defeat the safety ground connection.

7 INSTALLATIONS AND OPERATION 1. Stereo Operation: The PR-150 can be used in the Stereo Mode as two separate 150 watt units, each capable of driving loads down to 4 ohms. Each channel operates independently and has its own input connectors, sensitivity level controls, signal indicator LEDs, automatic limiter, fault protection circuitry, power amp, and speaker outputs. In the Stereo Mode, the Stereo/Mono Bridge switch must be set to the STEREO mode. One application of the Stereo Mode is using one channel of the amplifier for the left speakers and the other for the right. The mixing board channels can be panned left or right according to the position of the instruments on the stage. This way the sound is a more faithful reproduction of the live performance. 50Hz, 450W 2. Channel Patching: If many speakers must be driven from the same signal, it is possible to

8 slave or patch Channel 2 to Channel 1. One method is to connect a short cable from the unused Channel 1 input jack (either XLR or 1/4 ) to one of the Channel 2 input jacks. In this way, up to four 8 ohm speakers may be driven at once. The Stereo/Mono Bridge switch must be set to the MONO mode. 50Hz, 450W 3. Main/Monitor Combination: Another application of the Stereo Mode is using one channel of

9 the amplifier for the speakers and the other for the monitors. The Stereo/Mono Bridge switch must be set to the STEREO mode. 50Hz, 450W

10 4. Patching Two Bridged Mono Mode Systems: Two Bridged Mono amplifiers can be patched together by connecting a signal cable between their input jacks. The Stereo/Mono Bridge switch of each amplifier must be set to the MONO mode. 50Hz, 450W 50Hz, 450W

11 5. Mono Bridge Operation: The two internal power amplifiers can be bridged together to form a single, higher-powered amplifier this is especially useful when using the amplifier to power a subwoofer. In the Mono Bridge mode, the amplifier uses the Channel 1 input jacks and Sensitivity control (Channel 2 s are disabled). Channel 2 s power amp receives its signal from a tap after Channel 1 s Sensitivity control, but prior to Channel 2 s Limiter, so each channel is independently protected. The Stereo/Mono Bridge switch must set to the MONO position. Because both channels are being used (bridged in series), the minimum speaker load impedance must be 8 ohms. 50Hz, 450W

12 6. Triamping With Two Amplifiers: Two PR-150 can be used to separately power the lows, mids and highs of a three-way system. The Stereo/Mono Bridge switch of the amplifier driving the subwoofer must be set to the MONO mode. The Stereo/Mono Bridge switch of the amplifier driving the midrange and high frequency components must be set to the STEREO mode. Use Channel 2 for the high frequencies and Channel 1 for the mid frequencies. 50Hz, 450W 50Hz, 450W

13 7. Biamping With A Single Amplifier: A PR-150 can be used to separately power the lows and highs of a cabinet with biamp inputs, or a separate low and high frequency cabinet. For Biamp Operation, the Stereo/Mono Bridge switch must be set to the STEREO mode. Use Channel 2 for the high frequencies and Channel 1 for the lows. 50Hz, 450W

14 SPECIFICATIONS 8 Ohm/per Channel : 100W 4 Ohm/per Channel : 150W Watts Bridge 8 Ohms : 300W Frequency Response :+/-.35dB, 20Hz - 20KHz THD (1KHz) : 0.02% THD (20Hz-20KHz ) : < 0.06% Hum & Noise (S/N) : >101dB Slew Rate : 20 volts per nanosecond Input Impedance (Balance/Unbalance) : 20K Ohm / 10K Ohm Input Sensitivity : 1.0V RMS Load Impedance : >4 Ohm(Stereo mode) >8 Ohm(Bridged Mono mode) Protection : Short Circuit, over temp, speaker protection relays, RF burnout, turn on/off transient protection, DC protection and built-in auto-limiter. Cooling : Air fan. Power Requirements : 120 VAC 60Hz, 450W VAC 50/60Hz, 450W Dimensions : 483mm(W)x290mm(D)x44mm(H) Weight : 5.0kgs

15 The specifications contained herein are subject to change without notice.