Crown D-75 Service Manual

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4.5.2 Test Procedures
Test or Adjustment
I. Quiescent OC offset
2. Bias
adjustment
3. Power (s ingle channel)
4. Prot.ection Circuit
5. High Frequency
%
-
Rg. 4.1 2 Ohm Load Waveform
Input Signal
Characteristics
None
None
1 voit;IKHz
sine wave
1 voit;lKHz
sine wave
I vo l t; 10KHz
sq. wave
I voit;lKHz
sq.
wave
!
-
I.
Il'
•
Instructions/Comments
± lOmV
Positive output, base-emiuer junction should be between
.3V and .35V. Adjustable by RIl2, R212.
Into 8 ohms, 20 vrms ( SO watts) should be obtainable
before signal clip.
InlO 4 ohms, 11.5 vrms (75 walts) should be obtainable
before signal cJLp.
Int o 2 ohms, signal will appear as in Figure 4.1.
Into ar\ 8 ohm load, a 25 volt peak to peak: square wave
sig nal should exhibit no ringing (see figure 4.2)
Into an 8 ohm load, a 19vrms sine wave signal sh ould
exhibit no ringing (see Figure 4.3).
, ,
Fig . 4.2 10KHz Sq. Wave
Fig. 4.3 20KHz Sine Wave
Maintenance 4·3

Crown D-75 Specifications

General

Cooling	Convection cooled
Frequency Response	20Hz - 20kHz
Total Harmonic Distortion	<0.05% at rated power
Signal to Noise Ratio	>100 dB
Input Sensitivity	0.775V for rated power
Weight	10 lbs
Damping Factor	>400
Input Impedance	20 kOhms balanced, 10 kOhms unbalanced
Dimensions	19" W x 1.75" H x 8.5" D