What is stereo?

There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.

H.H. Scott '59

Quad FM4

 At the touch of button the Quad FM4 gives access to a variety, breadth and quality of programme material that the most dedicated gramophile would find difficult to equal. Indeed the emotional satisfaction which can be gained froma well engineered live broadcast is second only to being at the concert itself. A FM tuner is thus an essential piece of equipment for any serious listener to music. The FM4, as one might expect from Quad is deceptively simple and original. Good ergonomics and advanced electronics are combined to procedure a tuner with exceptional audio performance and ease of handling.

The Quad FM4 is designed as an adjunct to a high quality music system.  As such emphasis in design is placed upon obtaining audio performance from a reasonable input signal rather than the ultimate in selectivity.  Performance of the Fm4 is such that given adequate signal strength,  it makes no audible contribution to the incoming programme, and provides absolutely faithful reproduction of the original transmission.

The only controls on the FM4 are an on/off switch, tuning knob and eight pushbuttons which are used to store and recall stations in the tuner's memory. The tuned frequency is shown in figures and an ingenious bar graph display provides simultaneous information of signal strength and centre tuning. A specially developed dedicated imcroprocessor makes all decisions about muting and AFC and also controls the tuner's memory in which are stored the  preset stations.
 Operating the Quad FM4 issimplicity itself. Once programmed it is only necessary to press one of the seven preset buttons for the wanted station to be tuned in perfectly.
Programming stations into the tuner's memory is very straightforward. The desired frequency is located by rotating the tuning knob, which will have conspicuous advantages for anybody who has tried to find a station using pushbuttons to track up and down. The bar graph confirms that the station is correctly tuned and being received with sufficient signal strength to give acceptable signal to noise.
AFC and muting is taken care of automatically. Stereo over-ride, required if the signal is very weak, is achieved by switching the Quad 44 to MON and adjusting the balance control for minimum noise.
Programmes will remain stored in the tuner 's memory almost indefinitely provided that the tuner is used once in a awhile, and for up to five years even if it is disconnected from the mains.
When switched on the tuner remembers the station last used and automatically reverts to it.
Frequency Range:  88 - 108 MHz
-30  dB Quieting  [mono] :  1 µV 
50 dB Quieting [mono/stereo] :  2,7 µV / 25 µV
Full Limiting:  less than 1 µV
Signal-to-Noise Ratio (Input signal 1 kHz at 1 mV, A weighted):
Mono :  76 dB
Stereo :  70 dB
Distortion Input Signal (1 kHz):
±75 kHz [mono/stsreo] :  0-15%/0-15%
±25 kHz [mono/stsreo] :  0-05%/0-10%
Selectivity:  53 dB
Capture Ratio: 2-5 dB
IF Rejection:  100 dB
AM Suppression:  60 dB
Image Rejection:  80 dB
Pilot Tone Suppression:  60 dB
Crosstalk at 1 kHz:  40 dB
Frequency Response:  20 - 15 kHz :  +0 -1 dB
Output Level 30 % Modulation:  100 mV recommended load Impedance
Source Indepedance:  100 Ω
Recommended Load Impedance:  more than 20 k Ω
Aerial Input:  75 Ω unbalanced
De-emphasis:  50 µSec or 75 µsec)
Power Input:  100-125 or 200-250 50/60 Hz  6VA
Dimensions:  (W x H x D):  321 x 64 x 207 mm
Weight:  3 kg

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