Instruction Manual
DC-300A II Power Amplifier
Page 19
Construction
Dimensions: 19 inch (48.3 cm) standard rack mount
width (EIA std. RS-310-B); 7 inch (17.8 cm) height; 10.5
inch (26.7 cm) depth behind front mounting surface;
0.625 inch depth in front of mounting surface.
Weight: Net weight is 40 pounds, 11 ounces (18.5 kg);
Shipping weight is 45 pounds, 0 ounces (20.3 kg).
Finish: Carbide black front panel, splatter-coat black
chassis and top cover.
Chassis: All aluminum construction for maximum heat
conduction and minimum weight. Heavy aluminum
front panel is a single extrusion.
Heat Sinking: Massive black-anodized heat sinks are
thermally joined with the chassis, thereby utilizing the
entire amplifier as a heat sink.
Notes:
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 sine wave is presented to the amplifier over the range from 1 Hz to 20 kHz and the output is monitored for nonlinear distortion. The level at
each frequency is increased until the THD reaches 0.05%. At this level the average power per channel is reported.
4. A single cycle of sine wave is presented to the amplifier and monitored for nonlinear distortion. The average power during the burst is reported.
Speakers must be able to withstand this level if they are to be safely used with this amplifier.
5. A 40 millisecond burst or two cycles of 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 hearing
process.
6. EIA standard RS-490 (both channels driven).
D C - 3 0 0 A I I
Dual-Mono
Mode
Dual
(both channels
driven)
Bridge-Mono
(balanced output)
FTC Continuous Average
Power at 0.1% THD
(See note 1)
20Hz-20kHz 1 kHz
Single Cycle Tone Burst
Watts at <0.05% THD
(See note 4)
40 mS Tone Burst
Watts at <0.05% THD
(See note 5)
1 kHz 1 kHz
50 Hz20 Hz50 Hz20 Hz
EIA Watts
at 1% THD
(See note 6)
Max Average
Power at
0.1% THD
(See note 2)
Max Average
Power at
0.05% THD
(See note 3)
1 kHz
295
175
100
595
355
250
165
95
545
340
305
175
100
610
355
1 Hz-20 kHz
155
310
260
185
590
355
350
195
660
370
405
215
785
415
260
180
595
350
310
185
615
355
300
180
585
345
310
185
100
625
370
4
8
16
8
16
Load (Ohms)
Fig. 6.1 Power Matrix
Crown specifications are guaranteed for three years.
In an effort to provide you with as much information as possible about the high power-producing capabilities of your amplifier, we have created
the following Power Matrix. All specifications found in these tables are valid for 120 VAC, 60 Hz models and are guaranteed for three years. Some
spaces in the tables 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. One of the maximum average power columns 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. Full-bandwidth maximum average power measured at 0.05% THD
provides more reasonable, non-clipped conditions. Crown provides this specification with the hope that other manufacturers will also start
providing specifications that correspond to the way amplifiers are used in the real world—without a clipped input signal.
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.