Crown D-45 Reference Manual page 13

D-45 / D-75A Power Amplifiers
In an effort to provide you with as much information as possible about the power-producing capabilities of your amplifier, we have created the
following power matrix. The specifications found in these tables are for 120 VAC, 60 Hz North American units and are guaranteed for three years.
Some spaces in the matrix are left blank because we do not provide this same guarantee for those conditions—however, your amplifier will
perform well under all conditions listed in the table.
Power Specifications
When measuring power, 0.1% THD appears to be the industry standard for distortion. The maximum average power shown in the power matrix
is measured when THD rises to 0.1% so you can easily compare Crown specifications to those of other manufacturers. But this high level of
distortion actually allows for some clipping which is undesirable. The burst power specifications in the power matrix are measured at 0.05% THD
which is not a clipped condition. Crown has chosen to provide these specifications with the hope that other manufacturers will also start provid-
ing specifications that correspond to the way amplifiers should be used in the real world—without clipped output.
Many manufacturers publish power specifications with a tolerance of ±1 dB or worse. That means their amplifier can deviate more than 20% in
output! A 100 watt amplifier would meet their specification if it only produced 79.4 watts. Other manufacturers qualify their specs by saying they
are "typical, " "subject to manufacturing tolerances, " "single channel driven" or that they are specified with "fuses bypassed. " Each of these
statements effectively removes any performance guarantee. We take a different approach at Crown—our published specifications are guaran-
teed for three years. Further, because our "in-house" specs are more stringent than our published specs, every Crown amplifier will exceed its
published specs. We believe you should get what you pay for.
FTC Continuous Average
Power at 0.1% THD
Configuration (See note 1)
& Load (ohms)
20Hz-20kHz
4
Dual
8 20
(both channels
driven)
16 20
8
Bridge-Mono
(balanced output)
16 40
FTC Continuous Average
Power at 0.1% THD
Configuration (See note 1)
& Load (ohms)
20Hz-20kHz
4 45
Dual
8 35
(both channels
driven)
16
25
8 95
Bridge-Mono
(balanced output)
16 70
Notes:
All power matrix specifications are based on a 0.1% regulated 120 VAC, 60 Hz power mains and an ambient room temperature of 70° F (21° C).
1. Continuous power in the context of Federal Trade Commission testing is understood to be a minimum of five minutes of operation. Harmonic distortion is measured at the RMS sum
total as a percentage of the fundamental output voltage. This applies for all wattages greater than 0.25 watts.
2. A 1 kHz sine wave is presented to the amplifier and the output monitored for nonlinear distortion. The level is increased until the THD reaches 0.1%. At this level the average power
per channel is reported.
3. A single cycle sine wave is presented to the amplifier and monitored for nonlinear distortion. The average power during the burst is reported. Loudspeakers must be able to
withstand this level if they are to be safely used with this amplifier.
4. A 40 millisecond burst or a two cycle sine wave (whichever is of greater duration) is used and the power computed as the average power during the burst. The duty cycle of this
test is 10 percent. This power level is a measure of how loud an amplifier is as perceived by the human ear.
5. EIA standard RS-490 (both channels driven).
Crown specifications are guaranteed for three years.
D - 4 5
Max Average
Single Cycle Tone Burst
Power at
Watts at <0.05% THD
0.1% THD
(See note 2)
1 kHz 1 kHz 20 Hz
35 40
25 25 25
20 20 20
70 85
50 50 50
Fig. 4.1 D-45 Power Matrix
D - 7 5 A
Max Average
Single Cycle Tone Burst
Power at
Watts at <0.05% THD
0.1% THD
(See note 2)
1 kHz 1 kHz 20 Hz
50 55 65
40 40 45
25 25 25
105 110 140
75 80 90
Fig. 4.2 D-75A Power Matrix
(See note 3)
50 Hz 1 kHz 20 Hz
50 75 55
30 35 40
20 20 20
105 145 85
60
70 50
(See note 3)
50 Hz 1 kHz 20 Hz
85 120 65
50 60 45
30 30 25
165 235 140
100 130 90
40 mS Tone Burst EIA Watts
Watts at <0.05% THD at 1% THD
(See note 4) (See note 5)
50 Hz 1 kHz 1 kHz
60 60
40 40
20 20
85 85
50 55
40 mS Tone Burst EIA Watts
Watts at <0.05% THD at 1% THD
(See note 4) (See note 5)
50 Hz 1 kHz 1 kHz
70 70
45 45
25 25
140 140
90 95
Page 13
35
25
20
70
50
55
40
25
105
75