User manual NAD 7140

[. . . ] 9. AM Rod Antenna Antenna Terminals Coaxial Antenna Input Phono Input Phono Ground MM/MC Phono Selector CD Input Aux Input Tape Rec/Play 10. 17. Preamp Out, Main In Soft Clipping Speaker Impedance Bridging AC Line Cord AC Convenience Outlets (Not in U. K. model) Speakers A Speakers B 1 2 17 16 15 NAD ELECTRONICS, BOS1 (lN/l, ON!XJN/TOK INC. Y{) R s;:·~ ~;I~>~~> CAUTION: THE RISK TO REDUCE OF ELECTRIC SHOCK. DO NOT REMOVE COVER (OR BACK) NO USER-SERVICEABLE 4 1. [. . . ] In virtually all loudspeakers the useful output rolls off at frequencies below the woofer/cabinet resonance (which typically occurs between 40 and 70 Hz). The BASS EO circuit compensates for this rolloff, extending the useful response of the speakers significantly lower in frequency. The BASS EO circuit includes additional infrasonic filtering that rolls off the amplifier's response below 25 Hz to prevent inappropriate amplification of non-musical signals below the audio range. ·IIJII· II] . . ·. . , . . . . @' ~ . :®:-:®:. I. : ·· ; · II] . ~. Depress this button to switch on the receiver and any other equipment plugged into the SWITCHED convenience outlet on the rear panel. The digital frequency display will illuminate when the power is on. To switch the power off, depress the button again and release it. If you prefer, you may leave the receiver's POWER switch permanently engaged and use an external switch (such as a clock timer) to turn the power on and off. The circuit will provide proper drive signals for all conventional stereo headphones regardless of their impedance, with just one exception: electrostatic headphones usually are supplied with an adapter unit which must be connected directly to the speaker terminals on the rear panel. Before plugging conventional headphones into the PHONES jack, turn down the VOLUME control for safety. And when you are not listening to the headphones it is wise to unplug them from the PHONES jack. Otherwise, when listening to loudspeakers you might turn up the volume to a level that would feed excessively strong signals to the headphones and damage them. You may freely use headphone extension cables. If you want to use a headphone Y-connector to drive two headsets simultaneously, they should be identical models. Connecting together two headphones which differ widely in impedance usually will produce a substantial loss of volume in the headset having the higher impedance (or in both). 6 Of course very low frequencies are not found in all music, nor in all recordings, so the effect of the bass equalization often won't be obvious. Sometimes you may find that switching it in and out does not produce any noticeable change in the sound whatsoever, simply because the recording contains no energy at very low frequencies. But if your loudspeakers are capable of reproducing low bass, and if you play recordings in which low bass does have an important role, the BASS EO will make an audible (and occasionally dramatic) difference. If your loudspeakers already have extended and powerful deep-bass response, the BASS EO will still be useful to correct for the bass rolloffs engineered into some recordings. It also may be used to provide a subtle form of "loudness" compensation to restore subjectively flat frequency response when you listen to music at low volume levels. Three CAUTIONs should be observed when using the BASS EO feature: 1. This circuit is intended for use with loudspeakers having woofers eight inches (20 cm) or larger in diameter, preferably those with "long-throw" voice-coils and acoustic-suspension enclosures. It is not recommended for use with small "mini" speakers having woofers smaller than six inches; in most cases they are not designed to accept high power input at low frequencies and will only distort or suffer damage as a result. [. . . ] The signal strength meter is a series of five bars. The number of illuminated bars increases with the strength of the received signal. If only one or two bars illuminate, the signal is too weak for noise-free reception in stereo, but reception may be satisfactory in mono. Strong signals are indicated by four or five illuminated bars. [. . . ]