Crown Audio STUDIO AMPLIFIER - Manual (Page 29)

Page 29
Studio Reference IIIII & II II II II II
Professional Studio Amplifiers
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 matrices.
Minimum Guaranteed Power Specifications
Crown’s minimum power specifications represent the absolute smallest amount of output power you can expect from your
amplifier when it is driven to full output under the given conditions. Some spaces in each matrix may be left blank because the
same guarantee is not provided for those conditions—however, your amplifier will perform well under all conditions listed in
each matrix.
When measuring power, 0.1% THD appears to be the industry standard for distortion. Two of the maximum average power
specifications shown in each minimum power matrix are measured at 0.1% THD 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. Because
of this, a maximum average power specification at 0.05% THD is included in each minimum power matrix which represents non-
clipped conditions. Also, power at 0.02% THD is provided in the preceding specifications. Although most manufacturers do not
give power specifications at 0.05% or 0.02% THD, we encourage them to provide these specifications so you will have a more
realistic representation of the way amplifiers should be used in the real world—without a clipped output signal.
Many manufacturers publish power specs with a tolerance of ±1 dB or worse. This 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. In fact, some manufacturers
use these tactics to generate large power numbers, and they don’t even print a disclaimer. We take a different approach at
Crown—our amplifiers are
guaranteed to meet or exceed their specifications for three years. Further, because our published
8
Studio Reference I – Minimum Guaranteed Power (Watts)
Stereo/Mono
Mode
Stereo
(both channels
driven)
Bridge-Mono
(balanced output)
Parallel-Mono
16
4
FTC Continuous Average
0.1% THD + Noise
(See note 4)
1 kHz 20Hz-20kHz
750
1,490
785
1,575
1,565
Maximum Average
Load (Ohms)
AC Mains
120 VAC, 60 Hz
1 kHz
0.1% THD+N
(See note 1)
0.1% THD+N
(See note 2)
1,190
800
2,375
1,595
2,350
1,580
20Hz-20kHz
1,075
760
2,150
1,535
4
2
8
8
16
4
715
1,440
750
1,515
1,490
1,095
750
2,200
1,515
2,185
1,500
970
725
1,985
1,440
0.05% THD+N
(See note 3)
1 kHz
1,170
790
2,335
1,580
2,320
1,565
1,075
745
2,160
1,495
2,175
1,480
4
2
8
100 VAC, 50 Hz
Bridge-Mono
(balanced output)
Parallel-Mono
Stereo
(both channels
driven)
8
16
4
795
1,595
820
1,660
1,640
1,255
825
2,505
1,660
2,485
1,655
1,135
820
2,280
1,610
1,255
815
2,460
1,645
2,475
1,640
4
2
8
240 VAC, 50 Hz
Bridge-Mono
(balanced output)
Parallel-Mono
Stereo
(both channels
driven)
Fig. 6.1 Studio Reference I Minimum Power Matrix
specs are set below our “in-house” mea-
surements, you can expect
every Crown
amplifier to exceed its published minimum
power specs. We believe you should get
what you pay for.
Minimum Power Notes:
All minimum power specifications are based on
0.5% regulated AC mains with THD of less than
1.0% and an ambient room temperature of 70° F
(21° C). Standard EIA power (RS-490) is not shown
here because it is identical to FTC Continuous
Average Power.
1. A 1 kHz sine wave is presented to the ampli-
fier and the output monitored for nonlinear dis-
tortion. The level is increased until THD
reaches 0.1%. At this point, average power
per channel is reported.
2. A sine wave is presented to the amplifier over
the range from 20 Hz to 20 kHz and the output
monitored for nonlinear distortion. The level at
each frequency is increased until THD reaches
0.1%. At this point, average power per chan-
nel is reported.
3. A 1 kHz sine wave is presented to the ampli-
fier and the output monitored for nonlinear dis-
tortion. The level is increased until THD
reaches 0.05%. At this point, average power
per channel is reported.
4. Continuous power in the context of Federal
Trade Commission testing is understood to be
a minimum of five minutes of operation. Har-
monic distortion is measured as the RMS sum
total and given as a percentage of the funda-
mental output voltage. This applies for all watt-
ages greater than 0.25 watts.