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





Arcam Delta 80 tuner

 

"The tuner performed well and was simple to use. With strong FM signals it gave a clean and detailed stereo sound. The Delta 80 is thoroughly competitive and can be recommended as good value for money."

FM/MW/LW Digital Preset Tuner

With some of the best music now available from radio broadcasts and with live concerts providing the most natural listening material, the demands made on a quality tuner have increased A&R Cambridge has responded to this need by introducing the Arcam Delta 80 FM/AM tuner. Suitable for use with all stereo amplifiers, the Delta 80 produces a natural, smooth and detailed sound on FM, without the harshness or sibiliance associated with some other tuners. The Arcam Delta 80 combines its excellent sound quality with a modern appearance, the convenience of presets and a digital frequency display. As part of the new Arcam Delta range of electronics, the Delta 80 is the ideal complement to the Arcam Delta 90 integrated  amplifier and the Arcam Delta 70 compact disc player to be designed and manufactured in Great Britain.

 

The tuner's controls have been deliberately kept to a minimum to ensure simple, fuss free operation. Three interlocked push buttons are used for selection of the wavebands, each band using the flywheel assisted rotary tuning control for smooth, precise tuning, in addition a total of 12 programmable presets, 6 for FM and 6 for MW/LW, are always available for the convenient tuning of your favourite stations.

An easy to read, blue tinted 4-digit fluorescent display provides an accurate frequency readout across all three wavebands. A useful, logarithmically scaled, two colour LED signal strength meter is fitted. ( the first two LEDs glow amber when the signal strength is sufficient for good mono FM reception, with the first green LED also lit up the signal to noise ratio is good enough for stereo FM reception. The strongest and best FM or AM signal is of course indicated when all five LEDs are illuminated). On FM , A&R's proprietory three colour traffic lights LED tuning indicator makes accurate tuning really straightfor ward; in addition a green LED indicates when a stereo programme is being received.

For FM reception an AFC button is fitted to compensate for small drifts or any slight mistuning which may occur. A mono switch is provided to ensure better reception of weak FM stations.

 


Technical Design

The design of the Delta 80 has been realised using the highest quality components, selected for optimum sonic performance. Detailed theoretical analysis and extensive listening tests have produced exceptional results, the sound quality on FM in particular being firm, precise and clear.

In accordance with our experience in making some of the world's most acclaimed hi-fi amplifiers, liberal use is made of the best passive components, including precision 1% metal film resistors and close tolerance polystyrene and polycarbonate film capacitors. The tuner's front end uses dual gate MOS FET transistors for good RF performance and great care has been taken with the tuner's decoder circuitry and all power supplies in order to achieve the best sound. In addition an active low pass "birdie" filter is fitted before the stereo decoder to minimise the annoying whistles from adjacent stations which can sometimes interfere with stereo reception. A highly efficient multiplex output filter removes the 19 kHz and 38 kHz high frequency tones produced by the stereo decoder, preventing interference with the bias oscillators and Dolby encoders of tape recorders.

On the long and medium wavebands ceraful design has improved reception, especially on the "crowded" night time air waves resulting in a clearer, more informative sound.

 

Quality and reliability

Great care has been taken in every aspect of the design, construction and alignment of the Arcam Delta 80 tuner to ensure years of consistent, trouble free operation. The electronics are built in the traditional A&R manner using a single large fibreglass pcb fitted with proven high quality components, operated well within their ratings for long life and ease of servicing. Every tuner is rigorpusly checked at all stages of production, both for performance and appearance. Each unit is tested and aligned using advanced custom built equipment and is then "burnt-in" and finally retested before despatch to ensure ultimate reliability.

The Arcam Delta 80 tuner is provided with a ready made 75  dipole wire aerial for FM reception and a specially designed loop aerial for AM use. Nevertheless, for best results, in areas of anything but prime reception it is nearly always better to add appropriate external aerials in order to provide th etuner with the best possible input signal.

 


Specifications

FM Tuner Section

Tuning Range:  87,5 to 108 MHz

Sensitivity (IHF):  1,4 µV

Total Harmonic Distortion (95 MHz , reference 22,5 kHz deviation at 1 kHz):

Mono :  better than 0,15%

Stereo :  better than 0,25%

Ultimate Signal-to-Noise Ratio (CCIR/ARM)

Mono :  better than 74 dB

Stereo : better than 70 dB

Frequency Response:  20 Hz - 20 kHz ±0,5 dB (typically -2 dB at 15 kHz)

Channel Separation:  better than 40 dB (1 kHz)

Pilot Tone Supression:  better than 50 dB

Capture Ratio:  1,5 dB

Alternate Channel Selectivity:  better than 60 dB

AM Supression:  better than 50 dB

Signal Strength Meter:  5 LED type, logarithmic scale, usable from typically 10 µV to 2 mv aerial signal

AM Tuner Section

Frequency Range

MW :  530 - 1600 kHz

LW :  160 - 270 kHz

Distortion:  0,4% at 50% modulation

Ultimate Signal-to-Noise Ratio :  50 dB CCIR weighted, ref. 30% modulation

Genaral

Output Impedance:  2 k

Recommended load:  20 k  or greater

Output Level:  800 mv at 75 kHz deviation

Power Supply:  200 - 250 V AC only; 8 VA (100 - 120 V AC convesrsion possible)

Dimensions (W x H x D):  430 x 60 x 265 mm

Weight:  3 kg

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