Instruction manual

90
Australian
LAB REPORT LAB REPORTLAB REPORT
Modwright KWI 200 Integrated Amplifi er
TEST RESULTS
Newport Test Labs’ measurements of power
output showed that Modwright’s power
output claims (assuming they were intended
to apply when both channels were driven)
were met only at a frequency of 1kHz, where
the amplifi er delivered 221-watts per channel
into 8Ω and exactly 400-watts per channel
into 4Ω. When reproducing a 20kHz signal,
the KWI 200 managed only 180-watts when
driving 8Ω loads, and 306-watts when driving
4Ω loads. The differences are academic, of
course, as you can see by the dBw fi gures,
which show that the difference between an
output of 200-watts and one of 180-watts is
just 0.5dB—too small to be detectable by any
human ear. If Modwright’s specifi cation was
actually for just a single channel driven, then
the KWI 200 easily met its specifi cation into
both 8Ω and 4Ω loads except when the test
frequency was 20kHz and the load was 4Ω, in
which case it was only able to deliver an out-
put of 361-watts. Newport Test Labs also tested
the KWI 200’s power output into 2Ω loads,
for which the amplifi er isn’t rated at all, and
the Modwright was able to deliver 800-watts
at 1kHz with a single channel driven, and
602-watts per channel at the same frequency
when both channels were driven. What’s
more signifi cant is that it was able to deliver
almost the same power levels at frequencies
as low as 20Hz, which indicates the use of a
very high-quality power supply.
Frequency response was superbly
extended, with Newport Test Labs measuring
CONTINUED FROM PAGE 26
Modwright KWI-200 Integrated Amplifi er - Test Results
Test Measured Result Units/Comment
Frequency Response @ 1 watt o/p 2.2Hz – 180kHz –1dB
Frequency Response @ 1 watt o/p 1.0Hz – 190kHz –3dB
Channel Separation (dB) 88dB / 66dB / 42dB (20Hz / 1kHz / 20kHz)
Channel Balance 0.02 dB @ 1kHz
THD+N 0.4% / 0.4% @ 1-watt / @ rated output
Signal-to-Noise (unwghted/wghted) 80dB / 84dB dB referred to 1-watt output
Signal-to-Noise (unwghted/wghted) 98dB / 106dB dB referred to rated output
Input Sensitivity (CD Input) 37mV / 500mV (1-watt / rated output)
Output Impedance 0.7Ω OC = V
Damping Factor 11 @1kHz
Power Consumption 1.95 / 83 watts (Standby / On)
Power Consumption 107 / 664 watts at 1-watt / at rated output
Mains Voltage Variation during Test 242 – 251 Minimum – Maximum
Modwright KWI-200 Integrated Amplifi er - Power Output
Channel Load (Ω) 20Hz
(watts)
20Hz
(dBW)
1kHz
(watts)
1kHz
(dBW)
20kHz
(watts)
20kHz
(dBW)
1 8 Ω 220 23.4 234 23.7 200 23.0
2 8 Ω 210 23.2 221 23.4 180 22.5
1 4 Ω 420 26.2 422 26.2 361 25.5
2 4 Ω 390 25.9 400 26.0 306 24.8
1 2 Ω 760 28.8 800 29.0 544 27.3
2 2 Ω 578 27.6 602 27.8 450 26.5
Note: Figures in the dBW column represent output level in decibels referred to one watt output.