NAD 7400 User Manual

7400

Stereo Receiver

Date of manufacture : ? - Nov 89

Please note that this document contains the text from the original product brochure, and some technical statements may now be out of date

The 7400 Receiver (composed of circuitry from the 2400 Power Amp and 1700 Preamplifier/Tuner) was
designed according to the same principles as the 7l00, but it is approximately twice as powerful and has
additional refinements, including semi-parametric tone controls and convenient analogue style knob
tuning.

While the 7400 is conservatively rated at 100 watts per channel continuous power for test tones, its
Power Envelope circuit produces upwards of 370 watts per channel of long-term dynamic power for
music, with a peak current of 40 amperes for precise control of voice-coil motion with speaker
impedances as low as 2 ohms. For still more power, a rear-panel bridging switch converts the output
stage into a mono amplifier rated at 200 watts continuous power and 800 watts of tone-burst power
for music, The companion 2400 Power Amplifier may be added for stereo.

Semi-parametric tone controls combine the the simplicity of ordinary bass and treble controls with the
flexibility of a two-band parametric equaliser. Bass EQ) strengthens the deep bass while infrasonic
filtering prevents muddy intermodulation distortion. Ultra-quiet line-level circuits, including a feedback­operated volume control that reduces noise as its gain is lowered, provide a signal/noise ratio exceeding
that of any source, analogue or digital. Dual tape circuits (with independent two-way dubbing and
monitoring and external preamp-out/main-in connections make it easy to upgrade your system at any
time with an equaliser, surround-sound processor, or electronic crossover.

The sensitive and quiet tuner section of the 7400 is controlled by a rotary tuning knob and 14 presets,
combining the natural, intuitive feel of analogue tuning with the precision of digital frequency-synthesis.
Automatic station-seek tuning is included on the remote control. FM NR, selectable I.F. bandwidth, and
numerous internal refinements provide surprising station-pulling power and satisfying sound under
widely varying reception conditions.

PRE-AMP SECTION

Phono input

Input impedance (R and C) MM 47kΩ / 120pF

MC 47kΩ / 120pF

Input sensitivity, 1kHz MM 0.28mV ref. 1W

MC 0.02mV ref. 1W

Signal/Noise ratio (A-weighted with cartridge connected) MM 76dB ref. 5mV

MC 76dB ref. 5mV
THD (20Hz - 20kHz) <0.04%
RIAA response accuracy (20Hz - 20kHz) ±0.5dB

Line level inputs

Input impedance (R and C) 50kΩ / 250pF
Input sensitivity (ref. 1W) 15mV
Maximum input signal >10V
Signal/Noise ratio (A-weighted ref 1W) 96dB
Frequency response (20Hz - 20kHz) ±0.3dB

Line level outputs

Output impedance Pre-amp 600Ω

Tape Source Z + 1kΩ

Maximum output level >10V

Tone controls

Treble ±12dB at 3, 6 or 12kHz
Bass ±12dB at 50, 120 or 250Hz
Bass EQ +3dB at 60Hz

+6dB at 36Hz

Infrasonic filter (Switchable) -3dB at 12Hz, 12dB / octave

POWER AMP SECTION

Continuous output power into 8Ω * 100W (20dBW)
Rated distortion (THD 20Hz - 20kHz) 0.03%
Clipping power (maximum continuous power per channel) 130W
IHF Dynamic headroom at 8Ω +5.7dB
IHF dynamic power (maximum short term power per channel) 8Ω 370W (25.7dBW)

4Ω 400W (26dBW)
2Ω 440W (26.4dBW)

Damping factor (ref. 8Ω, 50Hz) >100
Input impedance 20kΩ / 600pF
Input sensitivity (for rated power into 8Ω) 1V
Frequency response 3Hz - 100kHz +0, -3dB
Signal/noise ratio ref. 1W 98dB

ref. rated power 118dB

THD (20Hz - 20kHz) <0.03%

Bridged Mode

Continuous output power into 8Ω * 200W (23dBW)
IHF Dynamic headroom at 8Ω +6dB
IHF dynamic power (maximum short term power per channel) 8Ω 800W (29dBW)

4Ω 880W (29.4dBW)

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