Technical information

Page 35
Com-Tech Power Amplifiers
Reference Manual
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 specifica-
tions 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 maxi-
mum average power specification 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 specifica-
tions 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
Fig. 6.1 Com-Tech 210 Minimum Power Matrix
Com-Tech 210 – Minimum Guaranteed Power (Watts)
Dual/Mono
Mode
Dual
(both channels
driven)
Bridge-Mono
(balanced output)
Parallel-Mono
FTC Continuous Average
At 0.1% THD
(See note 4)
1 kHz 20Hz-20kHz
Maximum Average
Load in Ohms
(Constant Voltage)
AC Mains120 VAC, 60 Hz
1 kHz
At 0.1% THD
(See note 1)
At 0.1% THD
(See note 2)
20Hz-20kHz
Dual
(both channels
driven)
Bridge-Mono
(balanced output)
Parallel-Mono
At 0.05% THD
(See note 3)
1 kHz
100/120 VAC, 50/60 Hz
Dual
(both channels
driven)
Bridge-Mono
(balanced output)
Parallel-Mono
220/240 VAC, 50/60 Hz
50 (70V)
4
2
100 (140V)
8
25 (70V)
8
4
16
50 (70V)
4
2
100 (140V)
8
25 (70V)
8
4
16
50 (70V)
4
2
100 (140V)
8
25 (70V)
8
4
16
150
110
110
300
220
205
295
215
210
145
110
105
290
220
205
290
215
210
150
115
105
300
230
215
300
225
215
135
105
105
270
210
200
135
105
95
265
210
195
140
110
100
275
220
200
145
105
110
295
215
205
290
210
205
145
110
105
285
220
205
285
210
205
150
115
105
295
225
210
300
225
215
140
105
110
270
210
205
275
215
205
135
110
100
275
215
205
270
210
205
140
110
105
280
225
210
275
220
210
125
100
105
250
205
200
125
105
95
250
205
190
130
105
95
260
215
195
saying they are “typical,” “subject to manufac-
turing 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 pub-
lished 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 Av-
erage 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 chan-
nel 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.