NAD T 747 A/V Receiver HT Labs Measures
Five channels driven continuously into 8-ohm loads:
0.1% distortion at 99.7 watts
1% distortion at 114.0 watts
Seven channels driven continuously into 8-ohm loads:
0.1% distortion at 66.8 watts
1% distortion at 79.8 watts
Analog frequency response in Bypass mode:
–0.13 dB at 10 Hz
–0.04 dB at 20 Hz
–0.06 dB at 20 kHz
–3.05 dB at 50 kHz
Analog frequency response with stereo signal processing:
–0.54 dB at 10 Hz
–0.16 dB at 20 Hz
+0.02 dB at 20 kHz
–44.13 dB at 50 kHz
This graph shows that the T747’s left channel, from CD input to speaker output with two channels driving 8-ohm loads, reaches 0.1 percent distortion at 122.6 watts and 1 percent distortion at 150.4 watts. Into 4 ohms, the amplifier reaches 0.1 percent distortion at 137.4 watts and 1 percent distortion at 197.1 watts.
Response from the multichannel input to the speaker output measures –0.13 decibels at 10 hertz, –0.04 dB at 20 Hz, –0.09 dB at 20 kilohertz, and –3.11 dB at 50 kHz. THD+N from the CD input to the speaker output was less than 0.026 percent at 1 kHz when driving 2.83 volts into an 8-ohm load. Crosstalk at 1 kHz driving 2.83 volts into an 8-ohm load was –74.11 dB left to right and –76.62 dB right to left. The signal-to-noise ratio with 2.83 volts driving an 8-ohm load from 10 Hz to 24 kHz with “A” weighting was –108.67 dBrA.
From the Dolby Digital input to the loudspeaker output, the left channel measures –0.04 dB at 20 Hz and –0.04 dB at 20 kHz. The center channel measures –0.04 dB at 20 Hz and +0.10 dB at 20 kHz, and the left surround channel measures –0.04 dB at 20 Hz and +0.11 dB at 20 kHz. From the Dolby Digital input to the line-level output, the LFE channel is +0.23 dB at 20 Hz when referenced to the level at 40 Hz and reaches the upper 3-dB down point at 81 Hz and the upper 6-dB down point at 100 Hz.—MJP
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