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

KEF K 140

The K 140 (1991-19993) was a direct descendent of the Coda II, III, IV which was a hugely successful loudspeaker both in the UK and abroad. A two-way system for use on a bookshelf or on stands, the K140 used a 200mm (8inch) bass driver to provide good bass performance and high output capability but was compact enough to fit neatly into a wide range of listening rooms.

KEF have an enviable track record when it comes to designing classic 200 mm (8-inch) two-way systems. The K 140 is no exception. Easily accommodated, and with no special installation problems, the K 140 has a prodigious that is, for such a compact speaker.
An 18 mm (0,75-inch) thickenclosure ensures low levels of cabinet colouration, and fast, detailed bass performance, with good weight and extension, when correctly positioned. This may be on a stand around 450 mm (18-inch) high, free-standing, or with some wall reinforcement. The 89 dB/2,83V/1m sensitivity ensures high output from moderately-powered amplifiers. The use of kapton for the bass unit's voice-coil former gives high efficiency with low distortion, thanks to its freedom from magnetic effectc and eddy current losses. Being thermally inert, it is well able to withstand the high temperatures generated during high-level replay. Careful equalisation using computer optimisation together with attracyive appearance, make the K 140 the system of choice for a thoroughly musical and outstanding all-round performance.

Specification: K140
System Type:  Two-way, shelf/stand-mount
Enclosure Type:  Closed box
Nominal Impedance:  8
Amplifier Requirements:  10 - 100 W
Frequency Response:  55 Hz to 20,000 Hz ±3 dB [at 2m on reference axis (-6dB at 45Hz)]
Sensitivity:  89 dB [at 1m/2.83V (anechoic conditions)]
Maximum Output:  109 dB on programme peaks under typical listening conditions
System:  SP3133
Drive Units:
Bass Unit :  B200 (SP1284),
Tweeter25mm  (SP1231)
Crossover:  SP2177
Dimension (W x H x D) : 490 x 260 x 246 mm (19.3 x 10.2 x 9.7 inches)
Weight:  8.75 kg (19.25 lbs)

KEF K 160

The K160 (1991 - 1993) offered a decent increment in performance over the K140 with the addition of a passive radiator in a larger enclosure volume. A two-way system for floor standing use, designed to be positioned away from the room boundaries, it offered the traditional KEF virtues of accurate tonal balance, realistic stable stereo imaging, together with good bass extension and high output capability.

This floor-standing loudspeaker is capable of reproducing music at realistic levels, yet is very campact, talking up well under one square foot of floor space. The K 160 employs a similar bass/mid and high-frequency complement as the K 140, but with an additional 200 mm (8-inch)passive radiator to provide added bass extension and output without the need for large power input. This additional bass diaphragm is specially designed to respondquickly and accurately to the low-frequency information contained in today's recordings. KEF's computer optimisation techniques, analysing the complex interaction between bass driver, passive radiator and enclosure, result in a bass extension that extends well below 50 Hz.

The K 160 is designed to operate clear of boundaries, floor-standing, or on low stands. Of high efficiency, the K 160 has a peak output capability of a massive 110 dB. Panel dimensions have been calculated to minimise resonances, whilst keeping the front baffle as narrow as possible, so as not to impair stereo imaging. The K 160 combines plentiful, extended bass, with a clear, articulate midrange and treble. It can play exceedingly loud, when required, and will appeal to those who like high levels, but with refinement.

Specification: K160
System Type:  Two-way, floor standing
Enclosure Type:  Passive radiator
Nominal Impedance:  8
Amplifier Requirements:  10 - 150 W
Frequency Response:  48 Hz to 20,000 Hz ±3 dB [at 2m on reference axis (-6dB at 40Hz)]
Sensitivity:  89 dB [at 1m/2.83V (anechoic conditions)]
Maximum Output:  110 dB (on programme peaks under typical listening conditions)
System:  SP3134
Drive Units:
Bass  unit :  B200(SP1284),
Passive  RadiatorBD200 (SP1289),
Tweeter :  25mm(SP1231)
Crossover:  SP2177
Dimensions (W x H x D): 750 x 260 x 246 mm (29.5 x 10.2 x 9.7 inches)
Weight:  11.8kg (26 lbs)


Discrete Three-Head Cassette Deck "SuperDIGIFINE" features:
Monitor-capable discrete 3-head configuration; "Fine" amorphous heads for better high-frequency response and low wear
Computer-controlled full-logic control
"Silent machanism" for driving head assembly
Closed-loop dual-capstan drive with direct-drive motor
Low-response designs; Die-cast aluminum base for mechanism, heavy, solid base for chassis, high-specific-gravity front panel, cassette-shell stabilizer, large insulators
2 "Direct" inputs for direct connection with CD player, etc.
PCOCC coil and lead wiring in heads, OFC plating on circuit boards for higher purity
Separate circuit construction for low interference
DC-configured amps an separate PC boards
High bias frequency for clear sound
Low-impedance voltage-tracking regulated power supply
Dolby HX-Pro and double-Dolby B/C noise reduction systems with MPX filter
Fluorescent Digital Peak Display, level meters and digital counter
Auto rec mute, Music Scan, Timer start (record/play), auto tape selector
Headphoe output with volume control
Bias and level controls for flat rsponse and sensitivity matching

Gold-plated terminals

Getting closer to digital sound in performance.
It's true that audio equipment has been becoming more and more elaborate in circuitry these years. But the more complex circuitry is, the greater there are chances that the signals will be compromised in the process. So in the TD-V1010TN cassette deck from the Super DIGIFINE series, JVC took the classic "less is more" approach.  Also in order to ensure pure and clean sound, JVC has employed a number of ways to damp and eliminate resonance and vibration.

Vibration-suppressing mechanical designs
In the TD-V1010TN, the precision base for the tape drive mechanism is built from rigid and heavy die-cast aluminum. The front panel is fashioned out of non-resonating high-specific-gravity resin, which is 1,5 times heavler and 1,7 times more rigid than the conventional front-panel material. During recording and playback, the cassette is held firmly in place by a stabilizing pad that damps resonance and vibration. A metal sheet is attached to the circuit board supporting the motor to stop the flywheel from vibrating. Further a massive brass weight is used for a reel recepracle to damp resonance and also improve rotating constancy. A solid and rigid base supports the entire chassis. Large insulators isolate the deck from sound pressure and external vibrations. And control knobs and switches are fashioned out of solid aluminum. This all adds up to pure and clean sound, especially from digital sound.

Closed-loop dual-caspian drive with direct-drive motor.
The TD-V1010TN employs perhaps the most sophisticated tape drive mechanism ever designed. With this drive, the portion of tape that runs across the heads is held laut dyring both recording and playback. One advantage of this sophosticated system is that it shuts out vibration and ther external disturbances, rsulting in reduced modulation noise. This gives you sound that is noticeably clearer and cleaner. And it improves head-to-tape contact for better response. The capstan is driven by a JVC precision high-torque coreless "pulse servo" motor which does not set up much vibration, further "cleaning" the taped sound.

3-head design for best response
The TD-V1010TN features three independent heads, one each for recording, playback and erase. This means since the heads are separate, each can be given the optimum gap width for best response. Moreover, the azimuth, tilt and tracking can be aligned head by individual head for best results - extended response and low noise. This discrete 3-headconstruction also enables you to monitor recordings as they are being made. There are separate circuits for Dolby encoding and decoding, so you can monitor Dolby-encoded recordings in real time.

"Fine" amorphous heads using PCOCC wiring
The record and play heads in the TD-V1010TN are made of newly developed "fine" amorphous material, which combines superior high-frequency response and our SA (Sen-Alloy) head's superior resistance to wear. For higher signal purity and clarity, we use PCOCC for the coils and leads in the heads. PCOCC is purest oxygen-free copper with single-crystal-like construction, featuring most efficient signal transmission and coloration-free sound reproduction.

Elaborate circuity for purer sound
Dc-servo playback amp
The playback amp features a low-noise FET differential input, cascade connection and DC servo system - an elabortae design usually featured in the phono equalizer of a quality amplifier. It has improved Signal-to-Noise  ratio by 3 to 4 dB.
High bias frequency.
The bias frequency is twice higher than normal at 210 kHz. This reduces bet noise due to interference of audio signals with the oscillator frequency.
Low-impedance voltage-tracking power supply
A highly regulated, low-impedance power supply is featured in the TD-V1010TN. Using a large capacity transformer and electrolitic capacitors, it automatically tracks positive and negative voltages to keep the ground potential zero and improve the stability of amplifier circuits. Moreover, our power supply exhibits extremely low output impedance across the audible frequency range. The result is even most dynamic musical passages or external noise cannot affect the steady performance of the power supply.
Separate circuit construction
In the TD-V1010TN, the audio amps, power supply and control circuits are mounted on separate PC boards, and insulated from each other, to shut out interference - both electric and magnetic. Furthermore, the deck uses circuit boards plated with OFC to ensure that the most delicate nunces are reproduced precisely.  Also contributing to cleaner sound is a fluorescent display off switch which turns off the display to prevent low-level digital noise.

Frequency Response at 20 VU:
Metal Tape :  10 - 22,000 Hz (15 - 20,000 Hz ±3 dB)
SA/Chrome Tape :  10 - 20,000 Hz (15 - 18,000 Hz ±3 dB)
Normal Tape :  10 - 20,000 Hz (15 - 18,000 Hz ±3 dB)
Signal-to-Noise Ratio:  61 dB (Metal)
Wow and Flutter:  0,022% (WRMS)
Crosstalk (1 kHz):  65 dB
Channel Separation (1 kHz):  40 dB
Total Harmonic Distortion (0 VU, 1 kHz):  1,0% (Metal)
T.H.D. K3 (0 VU, 1 kHz):  0,5% (metal)
Record/Playback :  Discrete 3-head configuration, fine amorphous heads for recording and playback
Erase :  Two-gap ferrite head
Input Sensitivity/Impedance:  80 mV/50 k Ω (direct input x 2)
Output Level/Impedance: 
Line Out :  300 mV/ 600 Ω
Headphones :  0 - 1 mW/8 Ω (matching impedance
Dimensions (W x H x D):  435 x 140 x 336 mm (17-3/16" x 5-9/16" x 13-1/4")
Weight:  10,3 kg (22,7 lbs)


Computer-Controlled Digital Synthesizer Tuner
The primary function of a tuner is bring in the station you want precisely and accurately, whether it's near or far. Using the latest circuit designs and device, we've made our tuner from the Super Digifine series, the FX-1010TN, more sensitive, selective and interference resistant than ever - the reason the tuner is able to provide wide dynamic range, low noise and low distortion, and wide frequency response. It's also extremely easy to use, thanks to the amazing power of an advanced microprocessor.

Reception servo for optimum reception from any station, almost anywhere. A built-in microprocessor detects the strength of a tuned station and compares it against the degree of interference from adjacent stations. Then, depending on the degree of interference, the microprocessor selects the optimum operation mode for front-end. IF and multiplex decoder stages (adjusting such parametersas RF gain, IF bandwidth, Quieting Slope Control and mono/stereo). Therefore when interference is excessive, a narrow IF bandwidth is automatically chosen to prevent noise. And if there's no interference, then a wide IF bandwidth is automatically selected to give you remarkably clear sound. When a signal level is overly strong, the RF gain is reduced to avoid saturation distortion; when it's weak, sensitivity is increased. Moreover, the tuner is equipped with inpuls to connect two antennas; each may be oriented for the best reception of stations in diametrical opposition to the other .
Conveninlly, the position of antennas, A or B, may be stored in memory station by station, which allows most precise reception from any station, without multipath distortion.
To add to convenience, the selected parameters are clearly indicated on a large fluorescent display, letting you quickly confirm tuning status.

Features for low noise and low distortion
JVC uses components and devices to ensure lowest possible noise and distortion and widest dynamic range from your favorite stations.
"Opticalink" System
This system is one developed by JVC to ensure highest purity from your favorite station. It uses eleven photocouplers (each consisting of a photoemitter and photosensor) to electrically decouple the analog from the digital section. As a result, interference between the two due to electric coupling is completely eliminated. This puts an end to digital noise and removes any trace of muddiness from the sound you hear.
In the FX-1010TN, each of the analog/tuner, digital control and "Opticalink" sections is mounted on its own PC board to shut outmutual interference and noise. And the digital control section, which can be a source of noise generation, is fully shielded to contain noise.

MOS FET front-end
The front end employs a dual-gate MOS FET which, along with high-Q varicaps, makes it as sensitive, selective and resistand to interference as a front end using an elaborate 5-ganged tuning capacitor. Therefore, the Signal-to-Noise ratio and interference rejection capability are outstanding.
Low-distortion IF section
The IF section of the FX-1010TN features ceramic filters coupled with a distortion reduction circuit for better phase response and low distortion
PLL detector and Beatless PLL multiplex circuit.
A PLL detector combines low distortion and high Signal-to-Noise ratio for dynamic and wide-range sound. Also the FX-1010TN uses a new PLL multiplex circuit that electrically filteres out beat noise-noise resulting from two or more frequencies interfering with one another. In a conventional CR-type MPX circuit using a VCO (Voltage Controlled Oscillator), however, a device called an "anti-birdie filter" is used to remove beat noise, but the coils in the circuit tend to degrade signal qulaity. In our beatless multiplex circuit, moreover, a pilot canceller is featured to suppress the leakage of the pilot signal, thus obviating the need for a 19 kHz filter, another component that would harm sound quality.
Active Filter
To prevent leakage of the 38 kHz subcarrier contained in a stereo broadcast, an LC filter built from coils and capacitors is commonly used, but, due to the magnetic distortion the core of the coil causes, this system tends to degrade sound quality in the FX-1010TN, however, an active filter; with coil eliminated, it provides better high-frequency response, wider separation and higher Signal-to-Noise ratio.

Computer-controlled operating ease.
With the help of powerful microcomputers, we've also improved tuning ease of the FX-1010TN tremendously.
Station name display
You can assign up to six alphanumeric characters to each preset station in the memory - "JAZZ-B", for instance.
Auto memory
All 40 FM/AM stations can be automatically tuned in sequence and committed to memory as presets.
Random preset memory
You can preset as many as 40 FM/AM stations in random oredr. There's numeric keypad that allows direct access to any of 40 stations.
Preset scan
All preset FM/AM stations can be automatically sampled one by one for approximately 5 seconds each
Preset cancel
Use this feature to skip undesired preset stations during preset scan
Program memory
Up to eight "events" (broadcasts) can be programmed for sequential recall under the control of an optional timer.
Auto QSC
The Auto Quieting Slope Control circuit automatically goes into action to reduce noise when a station signal is weak.
dB-referenced signal strength indicator
Read off the signal strength of a tuned station accurately down to 1 dB - a convenience when orienting antennas.
Variable stop level
Adjust FM/AM muting threshold in 5 dB steps over a range during auto tuning. The variable stop level feature lets you adjust the threshold from 20 dB to 60 dB for FM, and from 60 dB to 90 dB for AM. When you use a higher level, you'll receive only powerful, clear-sounding stations, with weak stations muted out. Or, when you choose a low level, all receivable stations are tuned in.
Record calibration signal generator
Record calibration signal generator outputs a standard 400 Hz signal for recording level adjustment.so, you can easily set the recording level for different broadcasts or types of tape.

FM Tuner Section (IHF)
Usable Sensitivity:  10,3 dBf (0,9 µV/75 Ω)
50 dB Quieting Sensitivity:
Mono :  14,8 dBf (15 µV/75 Ω)
Stereo :  38,1 dBf (22 µV/75 Ω)
Signal-to-Noise Ratio (IHF-A Weighted)
Mono / Stereo (aat 85 dBf) :  94 dB / 88 dB
Total Harmonic Distortion (1 kHz): 
Mono / Stereo :  0,009% / 0,02% (WIDE)
Capture Ratio:  1,2 dB
Selectivity (400 kHz):  25 dB (Wide); 75 (Narrow)
IF Response Ratio:  110 dB
AM Suppression Ratio:  65 dB
Stereo Separation (1 kHz):  60 dB (Wide)
Frequency Response:  20 Hz - 15 kHz (+0,3  -0,5 dB)
Antenna Input Impedance:  75 Ω unbalanced x 2
Output Signal Level:  600 mV (2,2 k ohms)
Rec Cal Output Level:  equivalent to 50 % FM modulation
AM Tuner Section
Usable Sensitivity :  250 µV /m (loop antenna)
Total Harmonic Distortion:  0,3%
Signal-to-Noise Ratio:  50 dB
Selectivity (±10 kHz):  35 dB
Image Response ratio:  40 dB
IF Response Ratio:  60 dB
Dimensions (W xH x D):  435 x 100 x 298 mm (17-3/16" x 3-15/16" x 11-3/4")
Weight:  3,7 kg (8,2 lbs)