Crown POWER-TECH 3 Reference Manual page 13

Power-Tech Series Power Amplifiers
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 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 spec at 0.05% THD is included in each minimum power matrix, which represents non-clipped conditions. Although most
manufacturers do not give you power specifications at 0.05% 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 specs are set below our "in-house" measurements, 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. International units with multi-tap
transformers are specified for the worst-case transformer tap (normally 100 VAC, 50 Hz).
1. 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.
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 the THD reaches 0.1%. At this level the average power per channel is reported.
3. 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 0.05%. At
this level the average power per channel is reported.
4. 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.
Reference Manual
Crown specifications are guaranteed for three years.
Fig. 4.1 Power-Tech 1 Minimum Power Matrix
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