Specifications

page 27
Studio Reference I & II Professional Studio Amplifiers
Operation Manual
7 Specifications
Crown specifications are guaranteed for
three years.
In an effort to provide you with as much informa-
tion as possible about the high power-producing
capabilities of your amplifier, we have created the
following power matrices.
7.1 Minimum Guaranteed Power
Specifications
Shown in Figures 7.1 and 7.2, Crown’s mini-
mum power specifications represent the absolute
smallest amount of output power you can expect
from your amplifier when it is driven to full out-
put 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 mea-
sured at 0.1% THD so you can easily compare
Crown specifications to those of other manufac-
turers. 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 manufactur-
ers qualify their specs by saying they are “typi-
cal,” “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 guaran-
teed to meet or exceed their specifications for
three years. 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 Con-
tinuous Average Power.
1. A 1 kHz sine wave is presented to the amplifier
and the output monitored for nonlinear distor-
tion. 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 channel
is reported.
3. A 1 kHz sine wave is presented to the amplifier
and the output monitored for nonlinear distor-
tion. 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. Harmonic
distortion is measured as the RMS sum total and
given as a percentage of the fundamental output
voltage. This applies for all wattages greater than
0.25 watts.