Crown DC300A Power Amplifier 电路图.pdf

w crolun INSTRUCTION MANUAL SERIAL NO ISSUED DC-300A DUAL CHANNEL LABORATORY AMPLIFIER DC-300A IM-9 S3P2-15-6 CROWN INTERNATIONAL, INC., BOX 1000, ELKHART, INDIANA 46514 RadioFans.CN 收音机爱 好者资料库 0 wcrown In-runaTlonac BATCH I D SERIAL NO Proof of Performance Report DCA-11 020163 DC-300A laboratory power amplifier Serial Number Line Voltage Requirementao,VAC Amcron Label CH.l 1. Quies. offset of less than 1OmV J 2. 1 KHz 180 wattsRMSminimum into 8 ohms, per channel, both channels operating, 0.1% total harmonic distortion 3. 4 ohm test 4. Protection tests 5. Reliability test 6. 20KHz 155 watts per channel minimum RMS (both channels operating) into 8 ohm. 0.05% total harmonic distortion 7. 10 KHz. sq. wave 8. Mono operation 9. IM Dist. into 8 ohms (%)z 155W (60-7KHz 4:1) S.M.P.T.E. -002 49.0W -002 15.5w *c?oJ. 4.9w _ cl03 1.55w _ Oj 490mW .00cc 155mW . 4 9 m W cci/ Y 15.5mW 10. Hum and noise-db below 155W into 8 ohm (20Hz - 20KHz)2 1 db CH.2 J ,/ la/db 11. Quies. AC power input at 120 VAC is a W see reverse side for explanation of tests performed RadioFans.CN 收音机爱 好者资料库 TOTAL PERFORMANCE IS WHAT COUNTS CROWN test and check-out procedures reflect our basic design philosophy; we believe that reliability can be engineered into a product. As such, our check-out is designed to expose and correct a problem, before it happens. This testing begins when the unit is still a pile of parts; grading and selection of components is standard. The final test-inspection is the culmina- tion of this vigorous program, but our concern doesnt stop here. Our products are backed by an extensive field service program, and protected by a comprehensive warranty. A word about our testing procedure is in order. All our specifi- cations are referenced to an AC input of 120 VAC. The high current demand with high power tends to cause the line voltage to sag, or the sinusoidal waveform to distort. With a distorted waveform (or lower line voltage) the peak voltage is lowered. Since it is the peaks that charge the filter capacitors in the amplifier power supply, and thus determine the maximum power output, a line voltage problem reduces the maximum power output. CROWN uses a peak equivalent AC voltmeter which measures the peaks of any waveform and converts this to an equivalent rms reading for a sinusoidal waveform. This way we can vary or regulate the line voltage, no matter how distorted the waveform, to an equivalent of a 120 VAC sinewave. We are then measuring a true maximum output power. With regard to the precision load which we use for our testing, we realize that a resistive load is quite different than a reactive speaker. However, using readily available parts, a precision resistive load is the easiest to duplicate, with respect to obtaining consistent results. We specify that the load must be resistive, having less than 10% reactive component at any frequency up to five times the highest test frequency. The resistance value should be maintained within 1%, at all power levels. The following discussion examines each of the test procedures listed on the facing page. This is an attempt to help you under- stand, in laymans terms, what the tests mean. Quiescent Offset - This simply assures that your amplifiers output is balanced with reference to its input. Thus the amplifier will not “bias” the program with a dc component. To meet specifications, offset must be less than 10 mv. 1KHz - This test measures the power across an 8 ohm load at a frequency of 1 KHz with both channels operating. This is a determination of how much power an amplifier can produce before a specified total harmonic distortion is reached. For the DC-300A, the power is 180 watts at less than .1% THD. 4 Ohm Test - This is a critical examination of the DC-300s performance at impedances below that for which it is rated. We check the wave form for level (it must reach a specified voltage before clipping) purity, and stability. 4. 5. 6. 7. 8. 9. 10. 11. Protection Test - This is a test with a 2 ohm load which determines the threshold at which the protection circuitry will be activated. Sharp clipping should occur with no evidence of instability. The positive and negative limiters operated independently and therefore may not be activated simultaneously. Reliability Test - This test puts the output stages through an extremely vigorous thermal cycling. The test is a very low frequency input signal driving the output to full power across a short circuit for a predetermined period of time. 20KHz - This tests the amplifier at its rated power level. We specify that at any frequency between 1Hz and 2OKHz the DC-300A will produce 155 watts minimum rms (both channels operating) into an 8 ohm load, at a sum total harmonic distortion of .05% or less. We choose 20KHz as the test frequency because high frequencies produce more heat than lower frequencies. Thus, if the amplifier can safely pass the 20KHz test, it will operate safely at lower frequencies. 10 KHz Square Wave - This test critically examines the amplifiers frequency response and rise time. (How fast the amplifier can follow rapid signal changes.) The output square wave (with an 8 ohm load) should be clean and sharp, with no ringing or overshoot. Mono Operation - This is a check for proper operation of the stereo mono switch. A signal is applied to channel 1 input only and the mono output is observed between the two red output terminals of the amplifier. IM Distortion Test - At CROWN we feel that IM distortion testing yields a truer picture of amplifier performance than harmonic distortion testing. While a large amount of documentation supports this opinion, some of the reasons are apparent, even in laymans terms. For example, a sinusoidal waveform (used in HD testing) bears little resemblance to the complex waveforms associated with actual program materials. IMD testing uses such a complex waveform. Also, harmonic distortion is not always aurally offensive. The human ear may interpret such distortion as pleasing, but usually finds IM distortion rather obnoxious. In order to support this design philosophy, we designed and built our own IM analyzer with residual noise and distortion low enough to test our amplifiers. Hum and Noise - This test, in plain English, tells you how small a signal can be amplified without it becoming “lost in the mud”. The test is limited to the audio band width of 20Hz-20KHz, with a bandpass filter. Our specification for the DC-300A is: hum and noise from 20Hz - 20KHz will be at least 110db below the full power output of 155 watts. This means that with a 155 watt output the noise will be only .00155 micro watts. (Thats 1.55 billionths of a watt ) Quiescent AC power Input at 120 VAC - This test confirms that your amplifier is not drawing excessive power while “idling”. If an amplifier exhibits a tendency toward instability, or oscillation, it may draw power with no signal input. The DC-300A will draw 40 watts or less at idle. RadioFans.CN 收音机爱 好者资料库 TABLE OF CONTENTS PAGE Section 1 DESCRIPTION 1 .1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2, 3, 4, 5 1 .3 Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Section 2 INSTALLATION 2.1 Unpacking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.2 Mounting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.3 NormalHi-FiInstallation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 2.4 Connecting Output Lines ., 14 2.4.1 Mono Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 2.5 ConnectingInputLines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 2.6 ConnectingPower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Section 3 OPERATING INSTRUCTIONS 3.1 Controlsand Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 3.2 TheProtectionMechanisms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3.3 Operating Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 3.4 LoadProtectionMethods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 3.5 Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Section 4 CIRCUITRY 4.1 Principlesof Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 4.2 Test Procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 4.3 Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Section 5 APPLICATION NOTES Application Note No.1 - V-lLimits of aLoad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 ApplicationNoteNo.2 - VFX-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 Application Note No. 3 - Speaker Protection . . . . . . . . . 29 LIST OF ILLUSTRATIONS TITLE PAGE l-l DC-300APictorial. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 l-2 DC-300A Performance Graphs I.M. Distortion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 HarmonicDistortion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Frequency Response. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 PowerResponse. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Phase Response. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 NoiseSpectrum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Crossta Ik. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ._. 8 NominalLimitsof V-l Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Damping Factor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 PowerEfficiency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Input Impedancevs.Gain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 2-l 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 3-l 3-2 3-3 3-4 3-5 Maximum Output vs. Load Impedance. 11 output (Z) .