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





Lafayette LR-3500


You won't and you can't
Because the LR-3500 is as good or better than any receiver around - including some that cost as much as half thousand dollars.
The top of the Lafayette line, the LR-3500 AM,FM and FM stereo receiver has all the features you've come to expect as the trappings of power. It'has state-of-the-art. Electronics, complete power controls to personalize the sound. 
The LR-3500 has more Continuous Power (RMS) than the Pioneer SX-737, Sony STR-7055, Sansui 771 and Kenwood KR-6400. Total Harmonic Distortion as low as the Pioneer and the Sansui. Better IHF FM Sensitivity than the Marantz 2250, the Sony, Sansui, Kenwood and Pioneer. And Capture Ratio that's better than the Sansui and equal to the Marantz and Kenwood.
Getting down to specifics, the LR-3500 puts out 47 Watts  per channel into 8 ohms from 20 - 20,000 Hz at no more  than 0,5% Total Harmonic Distortion. It has two tuning meters, two tape monitors, two stereo headphone output jacks, front panel tape output and mike inputs, FM MPX Phase Lock Loop Circuitry and loads of other features all packaged in a handsome walnut finish wood cabinet. And topped off with our 2 year free repair or replacement limited warranty on material and workmanship.
We know the Lafayette LR-3500 is a great $400 receiver because we've sold thousands of them at that price for years. But right now, it's an incredible $298 at your Lafaayette store.

It sounds too good to be true. But then, so does the LR-3500

UREI 813


Time Aligned™ Studio Monitor System
Features:
First Time Aligned™ monitor system designed for the professional studio
Features UREI 800 series TA™ network (patentpending)
6048G duplex with UREI custom H.F. horn for extended and more uniform H.F. response
Second L.F. 15" direct radiating driver fed from 3-way TA network for extended L.F. response and higher power handling capability at low frequencies
Graeter than 11,5 cu ft. Enclosure with pressure cotrol aperture for excellent L.F. damping, good efficiency and low distortion.
Unique enclosure damping method provides high efficiency conversion of low frequency aound pressure to adiabatic enrgy.

The 813 Studio Monitor System is the first generation product of a joint R & D effort of UREI and E. M. Long Associates. The Time Align™ Technique is a realtime design method, utilizing proprietary instrumentation developed by Long which allows the driver placements and network parameters to be adjusted simultaneously, achieving near perfect alignment of the frequency components of a complex transient waveform as heard by a listener.

The importance of time (phase) parameters of loudspeaker systems, in addition to smooth frequency response, has been postulated for many years. These group time delay anomalies may be severe in some multi transducer systems, although they may exhibit satisfactory or even excellent frequency response.
For stereo applications the model 813 Studio Monitor System is built in "mirror-image" (813 L, 813 R) to produce identical dispersion towards the listening position between two systems. The series 800 TA networks with the 800H custom H.F. horn, are also available separately in two way and three way configuration for both the 6048G and the 604E.

Specifications
Type:  Dual woofer coaxial with Model *#* three way TA network
Power Rating:  75 watts; 40 Hz to 20 kHz, with pink noise
Frequency Response:  ±3 dB, 40 Hz to 15 kHz measured "freespace" 4 πsteradians (H=5m, D=1m)
Sensitivity:  89 dB SPL/1V/1m
Impedance:  8 Ω, nominal (minimum impedance greater than 4 Ω)
Network:  UREI *#*, 3 way
Cabinet:  Utility flat black painted
Dimensions  with Grille (W x H x D):  914 x 787 x 622 mm (36" x 31" x 24,5")
Weight: 79,2 kg (176 pounds)

Kyocera R-861

If receivers have something of a bad reputation among serious audiophiles, there's a good reason, in Japan, where everybody owns compnent high fidelity, nobody owns one-piece receivers. In fact, North America may be the only place where receivers represent a majority of the market.
For most Japanese audio engineers, receivers are strictly for export. They're not serious components at all. So receivers are designed by the second-string engineers. This explains why even companies with decent separates tend to load their receivers up with meaningless knobs, buttons, and displays.
The irony here is that  there's no reason why receivers must be second-class components. There's nothing to prevent a company from using the same common sense and judgement in receiver design as they exercise with separates. This is the guiding philosophy behind Kyocera receivers.

 MOS FETS in the Driver Stage
A rarity in receivers, Metal-Oxide-Semiconductor Field Effect Transistors (MOS FETs) are used in the driver stages of all Kyocera receivers for their superior transient response and isolation characteristics.
Pre-Out/Main-In jacks
While it is hard to find a receiver with pre-amp output/ main-amp input jacks nowadays,, all Kyocera receivers have them. So you can connect outboard signal receiver as part of an elaborate multi-amp system. That's particularly important considering the multi-room capability of the Kyocera Full-System Remote Control network.
 The Kyocera R-861
Features
100 watts per channel (continous RMS both channels driven into 8 ohms from 20 Hz to 20 kHz with no more than 0,02% Total Harmonic Distortion
Compatible with Kyocera Full System Remote Control network
Manual/electronic volume control
Parametric bass, midrange and treble controls
Subsonic filter at 20 Hz with 12 dB/octave slope
High filter
Two tapemonitors with dubbing
Pre-amp Output/Main-amp Input jacks
MOS FETs in the amplifier driver stage for better dynamic performance
Toroidal transformer
Low-feedback design for reduced transient intermodulation distortion
Oxygen-Free Copper (OFC) wiring fo reduced noise
Moving Magnet/Moving Coil phono input stage
Female banana jacks bypass speaker switching for straight-wire-with-gain circuit
Quartz frequency synthesis tuning
FM front end with MOS FETs and High-Q varicaps for minimum interference
Ceramic IF filters for high selectivity, low distortion
Automated  IF bandwidth switching (Wide/Narrow) adapts to your reception conditions
High-frequency FM comparator for reduced noise
FM quadrature detector for low distortion
Switchable de-emphasis for Dolby FM broadcasts
Chopper type FM stereo demodulator for improved stereo separation
High blend switch for better sound on weck FM stations
7AM + 7 FM station presets
Specifications
Power Output RMS (both ch. Driven into 8 Ω with no more than 0,02% T.H.D., 20 Hz - 20 kHz):  100 W/ch
Dynamic Short-Term Power (at 1 kHz):
120 W/ channel at 8 Ω
180 W / channel at 4 Ω
230 W/ channel at 2 Ω
Total Harmonic Distortion (at rated power):  0,02%
Power Bandwidth (-3 dB re rated power):  10 Hz - 60 kHz
Intermodulation Distortion (at rated output,SMPTE):  0,02%
Slew Rate:  50 V/usec
Rise Time:  1,0 usec
Dynamic Headroom , 8 Ω :  1,0 dB
Input Sensitivity/Impedance:
Phono MC  :  125 µV/100 Ω
Phono MM  :  2,5 mV/47 k Ω/100 pF
Others :  150 mV/30 k Ω
Phono Input Overload  1 kHz, 0,5% T.H.D.:
phonoMC :  8 mV
PhonoMM :  150 mV
Signal-to-Noise Ratio (IHF short circuited, A-weighted, rated output):
Phono MC :  68 dB
Phono MM :  88 dB
Others :  100 dB
Turnover Frequencies:
Bass Control :  100 - 500 Hz
Midrange Control :  0,5 - 2,0 kHz
Trable Control :  2 - 10 kHz
High Filter (6 dB/oct) at 10 kHz :  -6 dB
Subsonic Filter (12 dB/oct) aat 188 Hz :  -3 dB
FM Usable Sensitivity (mono):  9,8 dBf
FM 50 dB Quieting Sensitivity
Mono :  14,8 dBf
Stereo :  35,8 dBf
FM Capture Ratio (Normal IF):  1,0 dB
FM Distortion, 1 kHz, Normaal IF
Mono :  0,06%
Stereo :  0,07%
FM Stereo Separation, Normal IF, 1 kHz:  58 dB
FM Frequency Response (30 Hz - 15 kHz):  +0 dB/-0,5 dB
FM Signal-to-Noise  Ratio, A -weighted
Mono :  82 dB
Stereo :  76 dB
FM Alternate Channel Selectivity:
Normal IF :  40 dB
Narrow IF :  81 dB
FM Spurious Rejction:  95 dB
FM IF Rejection:  120 dB
FM Image Rejection:  85 dB
FM Subcarrier product Ratio:  65 dB
Power Consumption:  320 W
Dimensions (W x H x D):  460 x 132 x 360 mm (18-1/8" x 5-3/16" x 14-3/16")
Weight:  12,3 kg (27 lbs)

Kyocera R-661


The Kyocera R-661
Features
70 watts per channel (continous RMS both channels driven into 8 ohms from 20 Hz to 20 kHz with no more than 0,02% Total Harmonic Distortion
Compatible with Kyocera Full System Remote Control network
Manual/electronic volume control
Parametric bass and treble controls with continuously variable turnover frequency for sensitive and precise tonal adjustment
Subsonic filter at 20 Hz with 12 dB/octave slope
High filter
Two tapemonitors with dubbing
Pre-amp Output/Main-amp Input jacks
MOS FETs in the amplifier driver stage for better dynamic performance
Toroidal transformer

Low-feedback design for reduced transient intermodulation distortion
Oxygen-Free Copper (OFC) wiring fo reduced noise
Moving Magnet/Moving Coil phono input stage
Female banana jacks bypass speaker switching for straight-wire-with-gain circuit
Quartz frequency synthesis tuning
FM front end with MOS FETs and High-Q varicaps for minimum interference
Ceramic IF filters for high selectivity, low distortion
Wide/Narrow IF bandwidth switch adapts to your reception conditions
High-frequency FM comparator for reduced noise
FM quadrature detector for low distortion
Chopper type FM stereo demodulator for improved stereo separation
High blend switch for better sound on weck FM stations
7AM + 7 FM station presets

Specifications
Power Output RMS (both ch. Driven into 8 Ω with no more than 0,02% T.H.D., 20 Hz - 20 kHz):  70 W/ch
Dynamic Short-Term Power (at 1 kHz):
80 W/ channel at 8 Ω
110 W / channel at 4 Ω
140 W/ channel at 2 Ω
Total Harmonic Distortion (at rated power):  0,02%
Power Bandwidth (-3 dB re rated power):  10 Hz - 60 kHz
Intermodulation Distortion (at rated output,SMPTE):  0,02%
Slew Rate:  50 V/usec
Rise Time:  1,0 usec
Dynamic Headroom , 8 Ω :  1,0 dB
Input Sensitivity/Impedance:
Phono MC  :  125 µV/100 Ω
Phono MM  :  2,5 mV/47 k Ω/100 pF
Others :  150 mV/30 k Ω
Phono Input Overload  1 kHz, 0,5% T.H.D.:
Phono MC :  8 mV
Phono MM :  150 mV
Signal-to-Noise Ratio (IHF short circuited, A-weighted, rated output):
Phono MC :  64 dB
Phono MM :  82 dB
Others :  100 dB
Turnover Frequencies:
Bass Control :  100 - 500 Hz
Trable Control :  2 - 10 kHz
High Filter (6 dB/oct) at 10 kHz :  -6 dB
Subsonic Filter (12 dB/oct) aat 188 Hz :  -3 dB
FM Usable Sensitivity (mono):  10,1 dBf
FM 50 dB Quieting Sensitivity
Mono :  15,5 dBf
Stereo :  36,5 dBf
FM Capture Ratio (Normal IF):  1,0 dB
FM Distortion, 1 kHz, Normaal IF
Mono :  0,07%
Stereo :  0,10%
FM Stereo Separation, Normal IF, 1 kHz:  55 dB
FM Frequency Response (30 Hz - 15 kHz):  +0 dB/-0,5 dB
FM Signal-to-Noise  Ratio, A -weighted
Mono :  80 dB
Stereo :  74 dB
FM Alternate Channel Selectivity:
Normal IF :  40 dB
Narrow IF :  75 dB
FM Spurious Rejction:  88 dB
FM IF Rejection:  110 dB
FM Image Rejection:  68 dB
FM Subcarrier product Ratio:  65 dB
Power Consumption:  210 W
Dimensions (W x H x D):  460 x 132 x 360 mm (18-1/8" x 5-3/16" x 14-3/16")
Weight:  11,7 kg (25 lbs)

Kyocera R-461


The  Kyocera R-461
Features
50 watts per channel (continous RMS both channels driven into 8 ohms from 20 Hz to 20 kHz with no more than 0,02% Total Harmonic Distortion
Compatible with Kyocera Full System Remote Control network
Manual/electronic volume control
Subsonic filter at 20 Hz with 12 dB/octave slope
High filter
Two tapemonitors with dubbing
Pre-amp Output/Main-amp Input jacks
MOS FETs in the amplifier driver stage for better dynamic performance
Low-feedback design for reduced transient intermodulation distortion
Female banana jacks bypass speaker switching for straight-wire-with-gain circuit
Quartz frequency synthesis tuning
FM front end with MOS FETs and High-Q varicaps for minimum interference
Ceramic IF filters for high selectivity, low distortion
6 AM + 6 FM station presets

Specifications
Power Output RMS (both ch. Driven into 8 Ω with no more than 0,02% T.H.D., 20 Hz - 20 kHz):  50 W/ch
Dynamic Short-Term Power (at 1 kHz):
80 W/ channel at 8 Ω
110 W / channel at 4 Ω
125 W/ channel at 2 Ω
Total Harmonic Distortion (at rated power):  0,02%
Power Bandwidth (-3 dB re rated power):  10 Hz - 60 kHz
Intermodulation Distortion (at rated output,SMPTE):  0,02%
Slew Rate:  40 V/usec
Rise Time:  1,5 usec
Dynamic Headroom , 8 Ω :  2,1 dB
Input Sensitivity/Impedance:
Phono MM  :  2,5 mV/47 k Ω/100 pF
Others :  150 mV/30 k Ω
Phono Input Overload  1 kHz, 0,5% T.H.D.:
Phono MM :  150 mV
Signal-to-Noise Ratio (IHF short circuited, A-weighted, rated output):
Phono MM :  80 dB
Others :  95 dB
Turnover Frequencies:
Bass Control :  200 Hz
Trable Control :  5 kHz
High Filter (6 dB/oct) at 10 kHz :  -6 dB
Subsonic Filter (12 dB/oct) aat 188 Hz :  -3 dB
FM Usable Sensitivity (mono):  10,3 dBf
FM 50 dB Quieting Sensitivity
Mono :  17,0 dBf
Stereo :  37,2 dBf
FM Capture Ratio (Normal IF):  1,2 dB
FM Distortion, 1 kHz, Normaal IF
Mono :  0,08%
Stereo :  0,12%
FM Stereo Separation, Normal IF, 1 kHz:  48 dB
FM Frequency Response (30 Hz - 15 kHz):  +0 dB/-1,0 dB
FM Signal-to-Noise  Ratio, A -weighted
Mono :  77 dB
Stereo :  72 dB
FM Alternate Channel Selectivity:
Normal IF :  55 dB
FM Spurious Rejction:  86 dB
FM IF Rejection:  100 dB
FM Image Rejection:  68 dB
FM Subcarrier product Ratio:  58 dB
Power Consumption:  175 W
Dimensions (W x H x D):  460 x 110 x 340 mm (18-1/8" x 5-5/16" x 13-3/8")
Weight:  8,2 kg (18 lbs)

Gale Gold Monitor

Gale Gold Monitor
The Gale Gold Monitor offers superior performance by utilising higher quality components throughout. This two-way design, with rear firing reflex port for extended bass performance also features a high power handling 19 mm ferro fluid cooled tweeter providing a more dynamic sound stage. Weight and clarity of reproduction is enhanced by high quality 4 mm 24 gold plated steel binding posts and a superior crossover design tuning the compact cabinet for maximum performance.
Whilst benefiting from significant performance increases the Gale Gold Monitors remain easy to drive, and this amplifier friemdly design is ideally matched with amplifiers ranging in power from 20 watts to 70 watts per channel.

Specifications:
Enclosure Type:  2-way reflex loaded
Drive Units
Low Frequency :  1 x 130 mm doped pulp bass unit
High Frequency :  1 x 19 mm fabric dome, ferro fluid cooled
Crossover:  4 element 1st order Zobel design
Connections:  4 mm, 5 way, 24 k gold plated binding posts
Frequency Response:  60 Hz -15 kHz
Sensitivity:  87 dB (1m/1watt)
Nominal Impedance:  8 Ω
Power Handling:  Amplifier rated from 20 W to 70 W
Construction and Finish:  Luxurious satin silver grey grain.
15 mm high density particle board enclosure and baffle
Enclosure Dimensions (W x H x D) : 267 x 177 x 167 mm

Gale Mini Monitor

 Gale Mini Monitor

The Gale Mini Monitor is a compact two-way loudspeaker with rear firing reflex port for added bass weight, especilly when positioned close to a rear wall. Designed with a moderately high efficiency rating, a nominal impedance of 6 ohm, and flat frequency response, the speakers are very easy to drive and are ideally matched with budget amplifiers ranging in power from 20 watts to 60 watts per channel.
This amplifier friendly compact loudspeaker is designed to be bookshelf, wall or stand mounted. These small babies demonstrate the effectiveness of the Gale 130 mm doped pulp cone bass drive unit, generating sufficiently large sound to fill small rooms without any distress. Treble is informative, the sound stage is deep and wide. High quality 4 mm 24k gold plated binding posts are fitted for maximum performance.

Specifications:
Enclosure Type:  2-way reflex loaded
Drive Units
Low Frequency :  1 x 130 mm doped pulp bass unit
High Frequency :  1 x 10 mm polymer dome, ferro fluid cooled
Crossover:  4 element 1st order Zobel design
Connections:  4 mm, 5 way, 24 k gold plated binding posts
Frequency Response:  60 Hz -15 kHz
Sensitivity:  87 dB (1m/1watt)
Nominal Impedance:  6 ohm
Power Handling:  Amplifier rated from 20 W to 60 W
Construction and Finish:  Luxurious satin silver grey grain. 
15 mm high density particle board enclosure and baffle
Enclosure Dimensions (wxhxd): 267 x 177 x 167 mm


Optonica SM-105H


Optonica SM-105H
Straight DC Stereo Integrated Amplifier with Fully Electronic Control System

This perfectly "straight" amp is a result of Optonica's efforts to provide a fully digital system based on a lead-less and contact-less design. A combination of fully direct-coupled amplifier circuitry and fully electronic controls for tone, volume and balance completely eliminated the use of lead wires to improve frequency response. Conventional mechanical controls were replaced with electronic circuitry to eliminate contacts. Microcomputer-controlled circuitry splits up the signal to ensure more precise tone control and offer a wider dynamic range, better Signal-to-Noise ratio, lower distortion and greater durability.
A full remote control system, unique graphic displays and an innovative sound memory system were added to match the outstanding performance of this amp.

Specifications
Amplifier Section
Music Output Power: 
2 x 77 W at 4 Ω (0,01% Total Harmonic Distortion; -22 dB Att)
2 x 60 W at 8 Ω (0,08% Total Harmonic Distortion; -22 dB Att)
Continuous Output Power (RMS, both channel driven) At 1 kHz :
2 x 50 W (4 Ω, 0,01% T.H.D.; -22 dB Att)
2 x 40 W (8 Ω, 0,08% T.H.D.; -22 dB Att)
Continuous Output Power (RMS, both channel driven) from 20 Hz to 20 kHz:
2 x 45 W (4 Ω, 0,05% T.H.D.; -22 dB Att)
2 x 37 W (8 Ω, 0,02% T.H.D.; -22 dB Att)
Total Harmonic Distortion:
Rated Power :  0,01% (-22 dB att)
Half Power :  0,01% (-22 dB att)
Power Pandwidth (IHF):  10 Hz - 35 kHz (0,1% T.H.D.; -22 dB Att)
Frequency Response
Phono:  40 Hz - 20 kHz (±0,3 dB) RIAA curve Deviation
Tuner, Aux, Tape :  7 Hz - 100 kHz (+0 dB, -3 dB)
Damping Factor (1 kHz, 4 Ω):  20
Signal-to-Noise Ratio (IHF-A): 
Phono:  78 dB
Aux : 95 dB
Phono Overload Level (1 kHz):  130 mV RMS
Tone Control
Bass :  ±8 dB at 100 Hz
Treble :  ±8 dB at 10 kHz
Audio Mutting:  ATT -50 dB (fixed)
Input Sensitivity/Impedance:
Phono :  2,3 mV / 47 k Ω; 120 pF
Aux, Tuner, Tape :  140 mV/10 k Ω
Output Level/Impedance
Speakers :  A, B (4 - 16 Ω)
Headphones :  Low Impedance (4 - 16 Ω)
Tape (Chinch) :  150 mV/220 Ω
Tape (DIN) :  45 mV/ 80 k Ω
General Section
Power Source:  110/220/240 V, 50/60 Hz AC
Power Consumption:  400 W (220V)
Dimensions (W x H x D):  430 x 95 x 320 mm
Weight:  7,8 kg

Optonica ST-105H


Optonica ST-105H
Microcomputer-Controlled Quartz PLL Synthesizer FM/MW/LW Stereo Tuner
Optimum reception with maximum convenience are combined innthis blend of precision electronic systems and state-of-the-art. Component parts. Designed to eliminate error and drift, this advanced electronic tuner employs a quartz PLL synthesizer tuning system to ensure super-precise, super-stable reception under all conditions. This precision is backed by an electronic input attenuator, a dual-gate MOS FET front end, ceraamic IF filters and a quadrature detector. A microcomputer controls both the audio search and station memory tuning systems to provide automatic location of receivable stations and one-touch tuning of favourite stations. A remote control station selection system, digital frequency display and air check calibrator function facilitate optimum use of this advanced tuner.

Specifications
FM Section
Frequency Range:  87,5 - 108 MHz
Antenna Input:  75 Ω unbalanced; 300 Ω balanced
Synthesizer Tuner:  yes
Span Frequency:  0,05 MHz
Automatic Tuning:  yes
Pre-Setting Station;  FM/AM total 10
Sensitivity :
Mono (DIN 40 kHz dev. Signal-to-Noise 26 dB):  1,3 µV (75 Ω); 1,6 µV (300 Ω)
Stereo (DIN 40 kHz dev. Signal-to-Noise 46 dB):  39 µV (75 Ω); 45 µV (300 Ω)
Total Harmonic Distortion (1 kHz, 40 kHz dev.):
Mono :  0,2%
Stereo :  0,3%
Signal-to-Noise Ratio (1mV, 40 kHz dev. 1 kHz):
Mono :  66 dB
Stereo : 61 dB
Frequency Response:  30 Hz - 15 kHz (±3 dB)
Image Rejection (at 98 MHz):  75 dB
IF Rejection(at 98 MHz):  75 dB
AM Suppression (modulated 30%, AM by 1 kHz and 100% FM by 400 Hz):  50 dB
Selectivity (±300 kHz, 40 kHz dev.):  45 dB (normal)
Capture Ratio:  2,5 dB (normal)
Subcarrier Suppression:  45 dB
Stereo Separation:
At 1 kHz :  40 dB
At 10 kHz :  30 dB
AM Section
Frequency Range: 
MW :  522 - 1610 kHz
LW :  150 - 372 kHz
Antenna:  Built-in ferrite bar antenna; External Antenna terminal
Synthesizer Tuner:  yes
Span Frequency:  auto 9 kHz, manual 1 kHz
Automatic Tuning:  yes
Pre-Setting Station:  FM/AM total 10
Sensitivity
MW :  350 µV/m (Signal-to-Noise 20 dB, 999 kHz)
LW :  350 µV/m (Signal-to-Noise 10 dB, 218 kHz)
Audio Section
FM Output (40 kHz dev.):  350 mV (fixed)
AM Output (30% mod.):  200 mV (fixed)
General
Power Sourece:  110/220/240 V 50/60 Hz AC
Power Consumption:  15 W (220 V)
Dimensions (W x H x D):  430 x 71 x 298 mm
Weight:  3,4 kg

KEF Model 103 Reference Series


With exceptional power handling for a compact loudspeaker Model 103 offers unique flexibility of installation and precise stereo image formation.
The drive units are centre-line mounted on a rotable, steel, speaker panel which can be turned (by successive right angles) through 360°. No matter how the system is positioned in the room the speaker panel may be placed to give the broadest, uniform, sound dispersion in the horizontal plane, ensuring accurate stereo imaging and the minimum of tonal variation.

Colouration
The greatest enemy of natural sound reproduction is colouration. It alters the tonal character of instrumental sounds, upsets balance and distorts acoustic perspective.
Colouration is mainly caused by uncontrolled vibrations in the drive units and the cabinet enclosure. The radiating diaphragms in KEF loudspeakers are made from highly damped plastic materials pioneered by KEF in conjunction with renowned organisations such as the BBC, the diaphragm of the low frequency unit in Model 103 is made of a specially formulated rubber-modified polystyrene laminated to a visco-elastic damping layer with a high internal loss factor. This construction effectively dissipates unwanted stored energy in the diaphragm thus preventing diaphragm colouration.
Coloruation due to cabinet wall vibration is reduced by internal bracing partitions and the use of laminated materials. Layered bituminous, anti-resonant linings effecticely cancel any remaining resonances.

Power Handling Capability
Wide range loudspeakers of compact size are necessarily inefficient and high power amplifiers make great demands on power handling capabilities if realistic sound pressure levels are to be achieved. The special motor construction of the Model 103 low frequency unit is designed fro low distortion and high heat dissipation. The anodised aluminium voice coil former and special heat resistant epoxy resin allow the coil to operate safely at temperatures up to 350°C whilst the advanced design of the magnet assembly ensures perfect magnetic linearity. Model 103 will handle the output from 100 watt amplifiers on musical programme.

Drive Units and Dividing Network
High Frequency Radiator T52 Type SP1049.
A new high frequency unit providing high power handling capabilities with exceptional transient response, wide dispersion and smooth frequency response.

Low Frequency Radiator B200 Type Sp1039.
This very special low/mid frequency unit is fitted with a coated Bextrene diaphragm and plasticised PVC cone suspension. The voice coil assembly will safely with stand short term overload to at least 350°C and continuous operation at 250°C

Dividing Network DN16 Type SP1050.
Capacitors selected to a 5% tolerance range and low hystersis ferrite cored inductors ensure close adherence to design crossover frequencies and slopes. Total harmonic distortion due to filter network is less than 0-1% at 50 watts (20V RMS)
 Environmental Adaptability
Model 103 provides broad, uniform sound dispersion for accurate stereo image formation. This is accomplished by centre-line mounting the low and high frequency unit very close together on a rigid steel panel with accurate matching of phase and amplitude between systems.
Accurate stereo image formation over the widest possible listening area also demands precise location of the loudspeaker systems. Multi-unit bookshelf systems can only provide maximum horizontal dispersion when used vertically or horizontally - but not both. When, for practical or visual considerations the systems cannot be used in the intended manner the acoustic performance will be degraded or compromises must be made.
Model 103 frees the user from these restrictions and anables positive stereo image formation whatever cabinet attitude is adopted. This is simply achieved by rotation of the steel speaker panel.
KEF engineers developed the rotatable speaker panel which permits Model 103 to be used on any of its four sides even in elevated locations

Specification:  Model 103
System Type:  Two-way, bookshelf/stand-mount
Enclosure Type:  Closed box
Input Impedance:  8 Ω
Rated Maximum Power:  100W programme
Amplifier Requirements:  25-100 watts per channel into 8 Ω
System Resonance:  58 Hz, Q=0.9
Nominal Frequency Range:  30 - 20,000 Hz 
Specific  Frequency Response:  50 - 20,000 Hz  ±2dB
Sensitivity:  25 watts into nominal 8 Ω produces 96 dB at 1 m and 400 Hz in anechoic conditions
Harmonic Distortion:  1% T.H.D. 100 - 20,000 Hz ralative to 96 dB SPL at 400 Hz, 3% T.H.D. at 50 Hz
Crossover Frequency:  3,000 Hz (electrical cut-off slope 18 dB/8ve)
Finishes:   Walnut, Teak
Grille:  black microcellularfoam
System:  SP1048
Drive units: 
B200 bass unit (SP1039),
T52 tweeter (SP1049)
Crossover:  SP1050
Internal Volume:  25,4 litres
Dimensions (W x H x D):  500 x 303 x 225 mm (19.7" x 13" x 8.9")
Weight:  19.5 kg (41,88 lb)

Creek 3140 FM Tuner

 CONTROLS and FUNCTIONS
Creek  have designed the 3140 to have the performance of laboratory equipment without the penalty of laboratory looks or complexity of use. Our philosophy is to design products with facilities which benefit the user rather than the reviewer, and which are different from those of other manufacturers because we try to think our designs through from the beginning, rather than trying to copy all the unnecessary functions which are normally provided to fill up space on front panels. We are sure that the functions we have incorporated in this tuner will make it very easy to use, so that you will constantly obtain the high performance of which it is capable.

Switch-on Stabilisation Delay
When the 3140 is switched on, a delay circuit waits for the internal control functions to stabilise before operation will start. This normally takes between 15 and 20 seconds. A further 2 seconds delay then occurs before the AFC system is enabled, ensuring that the tuner will return to the last station tuned before switching off.
-
Muting, Mono/Stereo, Blend and Tuning Indicator
Tuning accuracy is very important for high fidelity reception of FM broadcasts. The 3140 uses specially developed integrated circuits to allow exceptional tuning accuracy with great simplicity for the user. The same circuits also control the operation of the entire tuner to ensure that the best possible quality of audio is obtained at all times, automatically.
The Tuning Indicator, Muting, Blend and Stereo/Mono functions are operated by control signals derived from ICs from three parameters of the received signal – Detuning, signal/Noise Ration and Signal Strength. The Stereo/Mono and Muting functions are not simple on/off switching functions, but are progressive, proportional and carefully balanced against the three control parameters to ensure optimum listening performance but with extreme ease of use.

The control signals are monitored continuously, and are derived and perform control as follows:

Signal-to-Noise information is obtained by extracting a DC signal proportional to the non-audio content of the received and demodulated signal. The signals present above 75kHz are a function of the noise content of the demodulator output, while those below 10Hz are a function of inter-modulation and cross modulation products between adjacent channels. The subsonic content is also used to trigger the blend circuits in the presence of aircraft flutter, momentarily forcing the tuner to mono to reduce the irritation of this interference.

Signal Strength is extracted from the IF limiter, and is linearised to give control signal proportional to the RF at the aerial socket over a range greater than 80dB. This control signal is also used to operate the Automatic Gain Control (AGC) in the RF tuner head to prevent overloading in the presence of very strong input signals, and a further control signal is derived to ‘gate’ (or switch) the AGC operation, described below. The brightness of the frequency display is controlled by a derivative of the signal Strength monitor to give a clear indication of relative signal strength to the user.
 Detuning is a measure of the amount that the tuner is off-station. It is derived from the Automatic Frequency Control (AFC) signals, with further processing to obtain a linear control voltage proportional to the magnitude of the difference between the required station and the actual tuning point of the tuner. The Detuning monitor is also used to disable the AFC action between stations, described in more detail below.
 These various control signals are then combined to provide progressive control of the muting circuits and the stereo decoder. The operation of the system as a whole is best understood by examining in detail what happens as the tuner is tuned from an empty part of the band onto a strong station…

When the tuner is completely off-tune, and receiving no signals at all, then the Signal Strength monitor is at zero, the detuning monitor is at zero (cannot be de-tuned from nothing) and the signal/noise monitor shows zero (no signal – all noise). Combining thse signals on a ‘voting’ basis gives two out of the three voting for no signal worthy of any attention, and the audio output is held firmly muted. The stereo decoder is also forced to mono, but as there is no pilot tone signal for it to lock onto it holds itself in mono, anyway.

As we tune towards a station the Signal Strength monitor starts to rise, as does the Signal/Noise monitor (since the supersonic content of the recovered audio falls rapidly as a station is approached). However the subsonic content of the audio is now very high (due to the amplitude modulation products of the FM signal operating in the non-linear ‘skirt’ region of the IF filters) and the Detuning monitor shows that we are strongly off-tune, and so the audio is still held firmly muted by a two-against-one vote as before.

As we now tune more into the range of the IF filters, within 150kHz of the centre of the desired station (75kHz in Narrow mode) the Signal Strength monitor reaches its maximum, and (if the signal is strong enough) operates the AGC in the front-end. At this point the Stereo Decoder is released from mono, to allow it to lock onto a pilot tone if one is present, thereby lighting the Stereo Indicator. The proportional Stereo/Mono Blend is set by the (now stable) Signal Strength monitor to give the ‘amount’ of stereo available once the mute is finally released.
This is described in ore detail below.
If AFC is switched On it is also now released to take control of tuning, accelerating the tuner circuits rapidly into the centre of the station frequency. At the exact centre of the desired station the Detuning monitor returns to zero, and this un-mutes the audio output fully, and lights the Tuning indicator.
If the AFC is Off, then the muting is progressively released as the station centre is approached, lighting the Tuning indicator at the exact centre frequency when the mute is fully open. The monitor circuits continue to operate, so that if a burst of noise or interference is detected the mute will close briefly to prevent these unwanted signals reaching the amplifier.

The effect of the progressive muting function is to make the tuning knob seem to operate as a ‘clickless’ rotary switch. As the knob is turned through each station the tuner un-mutes at the point where the station is perfectly tuned, lighting the Tuning Indicator. This ‘switch’ effect is much more pronounced with the AFC switched Off. With AFC operating the T40 tunes rather like an AM radio – the station is apparently loudest at the point of perfect tuning, and gets quieter as you tune away to either side of this point. This makes it easy for those users unfamiliar with FM tuners to achieve the perfect tuning essential to obtain full FM performance. It is quite possible to tune a station entirely by ear, although the Tuning Indicator lights exactly at the centre point so it may be a little silly not to use it!
 Frequency Display
The green, digital frequency display indicates the frequency to which the tuner is actually tuned and is calibrated in MHz to a resolution of 100kHz.
Although the display cannot therefore show the correct frequency for one or two European broadcast stations which do not transmit on exact multiples of 100kHz (e.g. 95.125MHz), the tuning system in your 3140 will ensure that the tuner locks accurately to the centre of any channel to which it is tuned.
 More about Mono/Stereo and Blend
As mentioned earlier, the effect of going from mono to stereo is to require 20dB more RF signal to achieve the same audio signal-to-noise ratio. The 3140 incorporates a progressive changeover stereo decoder, which is controlled by the Signal Strength and Signal/Noise monitor signals. The decoder operates by mixing or blending the Left and Right stereo signals to give partial mono over a 20dB range of signal strength. The effect of this is to maintain an almost constant audio signal/noise ratio during the transition from full Mono to full Stereo. Even partial Mono is still very pleasing, certainly much more listenable than full, but 20dB noisier, Stereo. When the decoder is in the fully Mono condition the Stereo Indicator is extinguished, although the pilot tone oscillator is left running to maintain stability. This ‘Monoing’ can happen very quickly and briefly during flutter conditions, effectively masking this irritating interference.
The Blend Function is also controlled by the Signal/Noise monitor, so that in the presence of Adjacent Channel Interference (birdies) a degree of blend is introduced regardless of signal strength, reducing the audibility of this interference considerably.
The decoder’s oscillator operates at 76kHz, and is divided down to 38kHz to obtain the stereo sub-carrier, phaselocked to the 19kHz pilot tone. This feature makes the 3140 immune to birdie-like interference problems which result from other transmitted signals such s for the German VWF/ARI traffic information system, which operates on a 56kHz sub-carrier and is used in many European countries.
 More about AGC and AFC
The 3140 incorporates two additional features using its other signal monitors to enhance performance – Gated AGC and Detuning-limited AFC.
In some areas there are one or two very powerful local transmitters which can prevent reception of weaker stations adjacent to them in the FM band by dominating the front-end AGC. Normally the AGC signals are derived from the first IF amplifiers, which look at a10.7MHz wide ‘window’ onto the band. Obviously, one very strong station within this wide window will cause the AGC to reduce the sensitivity of the front end, preventing it from detecting any weaker signals in the same window. In the T40 an extra monitor signal is obtained from the second IF circuits, which look through a window only 300kHz wide (150kHz in Narrow mode).
If this second signal indicates that the AGC is reducing front-end gain due to a strong station outside the second IF window, and therefore not of interest, the AGC circuits are turned off, or ‘gates’. This allows reception of any weaker transmitters being masked by the presence of one dominant station elsewhere in the band.
Normal AFC control can also sometimes be self-defeating, since the AFC system must be a compromise between holding on firmly to the tuned station, and allowing the tuner to be deliberately moved to another one when wished. The two extremes of this trade-off either allow the tuner to drift away from the desired station too easily, or alternatively hang on to it permanently, preventing selection of a different station without first disabling the (‘grim death’) AFC.
In the 3140 the AFC is itself controlled by the detuning monitor, so that we can achieve very firm AFC once the desired station is tuned, but while actually tuning along the band there is no AFC action at all. The prevents the tuner from ‘flipping’ from one strong station to the next as it is tuned, missing out any weaker signals in between. This Detuning-limited AFC allows the 3140 to eliminate the compromise and use both extremes when appropriate, ensuring both easy tuning and then very stable locking to the required station.
Specifictions:
Tuning Range:  88 - 108 MHz
 Input Signal (for -3dB limiting):  0.7 µV
 Mono:
(S+N)/N=26 dB:  0,9 µV
(S+N)/N=46 dB:  2,2 µV
Stereo (channel separation 32 dB):
(S+N)/N=46 dB:  20 µV
Input Signal to Light Stereo LED:  5 µV
For 40 dB Separation:  20 µV
Stereo Channel Separation (for Vin better than100 µV):  46 dB
AM Suppression (at Vin = 1mV):  better than 50 dB
Total Harmonic Distortion (with input signal ± 75kHz):  less than 0,2%
Audio Bandwidth (-1dB):  25 Hz – 15 kHz
Pilot Tone Suppression:   more than 64 dB
Aerial Input:  300 Ω balanced and 75 Ω  unbalanced
Dimensions (W x H x D):  420 x 165 x 64 mm (16 ½ x 6 ½ x 2 ½”)
Weight:  3,3 kg  (7 lbs)