NAD 7140 - Manual

7140 S t e reo Receiver
Date of manufacture : Jan 87 - 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note that this document contains the text from the original product brochure, and some technical statements may now be out of date
NAD is internationally recognised as the value leader in Hi-Fi, and the new 7140 stereo receiver provides
an exceptional ratio of performance to price (even by NAD standards).
The tuner section of the 7140 combines the convenience and accuracy of digital frequency-synthesis
tuning with superior stereo sensitivity and quieting.
The phono preamplifier, too, is audibly (and in some cases dramatically) quieter than many other preamp
circuits, not only with moving-magnet pickups but also with low-output moving coil cartridges. The
entire amplifier circuit has ample dynamic range for every program source, including the widest-range
digital Compact Discs.
The powerful high-current output stage of the 7140 drives loudspeakers to surprisingly high volume
levels with clean, solid, full-bodied musical sound and a refreshing freedom from distortion, even in
transient peaks. The exclusive NAD impedance selector allows you to make maximum use of the
amplifier’s power regardless of the true impedance of your speakers.
The 7140 is conservatively rated at 40 watts/channel in the normal stereo mode, not only with test
resistors but with loudspeakers of any impedance. Its 3 dB of IHF Dynamic Headroom means that it will
deliver fully double its rated power (over 80 watts per channel) in brief bursts, important for undistorted
reproduction of the uncompressed transients in Compact Discs and DBX-encoded recordings.
Digital-ready design
The receiver’s line-level inputs will not be overloaded by high-level signal peaks from a Compact Disc
player or digital tape recorder. The 102 dB signal-to-noise ratio of the 7140 exceeds that of any
analogue or digital program source. The low-impedance, low-noise design of the volume and tone
control circuits guarantees that the transparent clarity of the finest analogue and digital recordings will
be preserved.
Low-noise MM/MC phono preamplifier
The phono preamplifier in the 7140 is a discrete (non-IC) design featuring a matched pair of extremely
low-noise transistors in a differential input circuit. It interfaces correctly with the impedance of magnetic
cartridges, and a rear-panel MM/MC selector increases the circuit gain by 20 dB for low-output moving-
coil pickups. The preamp has a push-pull output circuit, like a miniature power amplifier, that provides
ample current to drive the precision RIAA equalisation network without slewing distortion, and its large
dynamic range (107 dB) comfortably accommodates all digitally-mastered LP recordings with room to
spare.
As long as LPs remain a principal music source for many listeners, there must be no compromise in the
quality of the phono preamp circuit.