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





Pioneer CT-F 8282

 Front-Access 2-Motor Solenoid Operated Stereo Cssette Deck with Dolby NR, peak level Indicator, Ferrichrome/Chrome/Standard Biass and EQ, Memory Stop and Other Features for better Performance.Features
Pioneer exclusive front loading design
Twin-link design improves tape performance
Two-motor, high performance drive system
Soft-touch solenoid controls
Chage tapes without changing mode
Ferrichrome/Chrome/Standard EQ and bias
Wide range three-stage preamplifier
Less noise from FM recording
Input selector switch
Memory stop and tape ednd indicator.
 Pioneer has incorporated all the latest innovations in cassette deck design into one reasonably-priced, high-performance package that is sure to meet your every need. In many cases our engineers have throughly re-designed a particular feature to extend a its benefis under conditions that match actual use. A good example is the front-loading, front-access design itself. An ingeniously engineered, easy-to-handle tape compartment opens up the full potential of cassette tapes by increasing convenience without sacrificing quality performance. Your tapes are positioned vertically, held securely at all times by a twin-link mechanism. You can easily observe tape movement and direction, and even read tape labels. Changing tapes is literally a "snap". The 2-motor drive system in the Pioneer CT-F 8282 also makes a lot of sense and saves a lot of wear and tear. A cspecial DC high-torque motor provides super-stable tape transport in Play and Record modes, while another miniature powerhouse delivers fast rewind and fast-forward operation. Special electronics and greatly improved convenience features round out the CT-F 8282, from Pioneer.
 Adds new Dimension to Audio Enjoyment
Fast and easy front panel operation is achieved through carefully apportioned control layout and Pioneers's original vertical cassette transport system. Simple stand up cassette loading makes handling effortless.
High Reliability 2-Motor Transport
Tape motion during record and playback is regulated by a superbly stable DC servo controlled motor, while a high torque mechanical governor equipped motor drives fast forward and rewind. Precision design and finishing of the capstan, belt, large size flywheel and tape take up mechanism assure outstanding performance in terms of wow and flutter and stability.
Select Transport Modes Directly
Direct chaange system allows any mode (record, play, fast forward, rewind) to be selected without alternating with the stop switch. Operating convenience becomes additionally increased, while tape is protected from undue stress.
Reduced Tape Noise with Built-in Dolby System
Without adversely affecting the sound quality of the program source, the built-in Dolby system can significantly reduce bothersome tape hiss noise (by up to approximately 10 dB at high frequencies). Wide dynamic range, excellent S/N ratio recording and plauback can be fully enjoyed.
3-stage Direct Coupled Head Amplifier
Equalization and microphone amplifiers are comprised of 3-stage direct coupled circuitry to provide excellent phase characteristics. Application of effective negative feedback up to ultra high frequencies assures stable high frequency response and a dynamic range exceeding 40 dB of the base level.
 Tough and Durable Ferrite Soild head
Ferrite solid composing the record/playback head resists abrasion and features long durability, superior high frequency response and head touch, in addition to minimized problems of dirt adhesion and magnetization noise.
Independent Bias and Equalization Selection
Nearly all types of tape can be employed, including chrome, low noise, ferrichrome and standard, by providing separate settings for bias and equalization. The special qualities of each type become fully experienced. A new equalization design (3180 +70 µs) is included and the electronic switching circuit eliminates switching noise.
Large Level Meters and LED Peak Indicator
Large size, easy to see level meters are mounted on the front panel together with a light emitting diode (LED) peak indicator which advises of instantaneous over levels. Reliable signal monitoring can be performed, permitting low distortion recording of wide dynamic range program sources.
Quality Convenience Features
Memorey Stop Switch - employ during recording or playback by simply pressing the memory button and resetting the counter at the beginning of the desired passage. When the passage is completed, press the rewind lever. The tape will then rewind to the selected point and stop automatically.
Input Selector Switch - selects between Line (pin jack) and DIN jack input signals. By setting to DIN when recording with microphones, microphone input level can be attenuated by 10 dB.
Specifications
Systems:  Compact cassette, 2-channel stereo
Motors: 
1 x Electronically-controlled DC motor (built0in generator);
1 x Dc torque motor (4,8 cm/s speed drive)
Heads:
1 x Ferrite Solid recording/playback
1 x ferrite erasing
Operation:  Solenoid drive, direct switchable and time play presettable
Fast Winding Time:  Approx. 65 sec. (C-60 tape)
Wow and Flutter:  No more than 0,07% (WRMS)
Frequency Response: 
Standard, LH Tapes : 20 - 16,000 Hz (30 - 13,000 Hz  ±3 dB)
Chromium Dioxide Tape : 20 - 17,000 Hz (30 - 15,000 Hz  +_3 dB)
Ferri-chrome Tape : 20 - 17,000 Hz (30 - 15,000 Hz ±3 dB)
Signal-to-Noise Ratio (Dolby OFF/ON):  More than 53 dB/63 dB
Harmonic Distortion:  No more than 1,5%  (0 dB)
Inputs (Reference Level/Max. Allowable Input/Impedance):
Mic x 2 :  0,2 mV/100 mV/50 k Ω
Line x 2 :  60 mV/25 mV/100 k Ω
DIN (Rec/Pb) x 1 :  Input & Output,  5,5 mV/3,6 mV/8,7 k Ω
Outputs (Reference level/Max level/ Load Impedance):
Line x 2 :  450 mV/660 mV/50 k Ω
Headphones x 1 :  60 mV/98 mV/8 Ω
DIN (Rec/Pb) x 1 :  450 mV/660 mV/50 k Ω
Semiconductors
Amplifier Section:  60 Transistors;  40 Diodes;  4 Zener Diodes; 4 FETs; 2 LEDs; 1 Hole elementary
Motor Coontrol Section:  3 Transistors; 1 Diodes
Subfunctions:
Dolby System (ON/OFF) with indicator lamp
Tape Selector (STD/CrO₂/FeCr) with CrO₂ indicator lamp and manual tape selector of independently Bias/EQ (Ferri-chrome tape available)
Cassette compartment illumination
Memory stop mechanism (ON/OFF) with indicator lamp
Recording peak level indicator (lightable level 5 dB)
AC outlet (unswitched)
Powe Requirements:  AC 120 , 220, 240 V  50/60 Hz
Power Consumption:  54 watts
Dimensions (W x H x D):  452 x 193 x 348 mm (17-3/4" x 7-5/8" x 13-3/4"

Weight:  12,5 kg  (27,6 lbs)

Hitachi HS-330

 Hitachi has created the metal Cone Speaker because we believe it is superior  to speakers made with paper cones. Paper cones are fine but they have a tendency to respond partially and not "whole-heartedly" to a signal coming from the amplifier.
In other words, as the voice coil pushes or pulls at the cone center, part of the cones respond correctly while other parts don't.

 What is needed is something piston movement. A material with free circumferential elongation and contraction.  The result of extensive research into all possible (and sometimes impossible) cone materials. Hitachi's engineers created the Metal Cone with perfect low resonance characteristics.
Light,rigid, it also possesses a "gathered edge" supporting the metal cone firmly without disturbing piston movement.  Altogether producing far less distortions than conventinal paper cones.
It responds "wholeheartedly" and not partially giving your music full power of expression.
You might even say it gives your music an edge.
 Paper has always been the traditional material for even the finest speaker systems. Unfortunately, a paper cone doesn't move evenly over its entire surface, which results in uneven frequency and transient response - or "breakup distortion".
So Hitachi engineers overcame that problem by using metal cone diaphragms for the woofer, mid-range and tweeter combined with a peak control circuit which eliminates any possibility of cone resonance affecting sound quality.
 Then, a patented Gathered Edge suspension design was applied to the woofer which prevents lateral vibrations causing distortion, while at the same time, allowing a greater dynamic bass response.
We believe this unique pair of performers are the most exciting, lifelike, distortion-free speakers we've ever heard.  More important, we think you'll agree.
Specifications

HS 330
Type:  3-way, 3-speaker bookshelf type
Speakers:
Woofer L-253:  250 mm (10") Sandwiched Metal Cone Gathered Edge
Midrange M-65: 65 mm (2½") Metal Cone
Tweeter H-40:  40 mm (1½") Metal Cone
Max. Input (Peak):  100 Watts
Frequency Response:  40 - 18,000 Hz ±4 dB
Sensitivity:  82 dB (2,83 V/1m)
Crossover:  900 Hz;  3,500 Hz
Impedance:  6 Ω
Enclosure Volume:  40 l
Dimensions ( H x W x D):  575 x 315 x 305 mm

Weight:  13 kg

Hitachi HS-530

 Hitachi presents Metal Cone Speakers and Gathered Edge Woofer, a tottaly new approach to loudspeaaker design.
Paper has always been the traditional material for even the finest speaker systems. Unfortunately, a paper cone doesn't move evenly over its entire surface, which results in uneven frequency and transient response - or "breakup distortion".
 So Hitachi engineers overcame that problem by using metal cone diaphragms for the woofer, mid-range and tweeter combined with a peak control circuit which eliminates any possibility of cone resonance affecting sound quality.
Then, a patented Gathered Edge suspension design was applied to the woofer which prevents lateral vibrations causing distortion, while at the same time, allowing a greater dynamic bass response.
We believe this unique pair of performers are the most exciting, lifelike, distortion-free speakers we've ever heard.  More important, we think you'll agree.
Specifications
HS 530
Type:  3-way, 3-speaker bookshelf type
Speakers
Woofer L-251: 250 mm Sandwiched Metal Cone Gathered Edge
Midrange M-55 :  55 mm Metal Cone
Tweeter H-22 :  22 mm Metal Cone
Max. Input (Peak):  120 Watts
Frequency Response:  35 - 20,000 Hz
Sensitivity:  82 dB (2,83 V/1m)
Crossover:  900 Hz;  3,000 Hz
Impedance:  6 Ω
Enclosure Volume:  40 l
Dimensions ( H x W x D):  630 x 350 x 270 mm

Weight:  17,8 kg

Acoustic Research Receiver

 The earliest high-fidelity components were designed during the vacuum-tube era, and generally followed broadcasting practice in separating tuner, power amplifier, preamplifier and power supply, each circuit section on its own chassis.
The characteristics of transistors, primarily their small size, cool operation and indefinitive service life, permit the consoloidation of all of the electronic circuitry needed in a high-fidelity system into one component, the receiver.
The AR silicon solid state FM receiver is an integrated stereo FM tuner, stereo preamplifier and power amplifier, mounted on one chassis.  FET front end with 4-section capacitor, multisection crystal IF filter, IC IF amplifiers, and 2µV sensitivity insure superb FM reception.
 The AR receiver was under development for some time. When the amplifier section was completed, several years ago, it was offered to the public as a separate component.  High Fidelity, citing test reports from CBS laboratories, stated, "It is, in our view, an unqualified success, a truly excellent and unimpeachable amplifier … (at 20% more than its rated power) it either met or exceeded it specifications … the IM distortion characterisctics must be counted as the best we've ever seen …" Stereo Review called the amplifier's power "staggering", and added, "it ranks among the very best available."
 Circuit Characteristics
(FM) FET front end with 4-section variable capacitor;
Multisection crystal IF filter;
IC (integrated circuit) IF amplifiers;
Automatic interstation noise suppression with defeat switch for very weak stations;
Automatic mono/stereo FM switching with stereo indicator light;
Low-distortion shunt multiplex detector;
Tuning meter.
(Amplifier) DC driver clamping for clean overload recovery;
Idling power supply eliminates turn-on transient noises;
Bass and treble separately controlled for each channel;
Differential loudness compensation curves in bass control circuit;
Special null circuit permits exact balancing of stereo source material;
Stable under short-circuit of output terminals;
Line fuse, speaker fuse and self-resetting circuit breakers for full protection.
The AR receiver is guaranteed for 2 years from date of purchase.
 The receiver has now been completed by the addition of the circuitry required for stereo FM broadcast reception which is in every respect the counterpart of the performance of the amplifier. The receiver circuit is all-silicon solid state; the most rigorous manufacturing and inspection techniques we know are used in its assembly. The receiver is guaranteed for 2 years
While no compromise is made with optimum performance, the AR receiver is lower inprice than might be expected. This is because of the rational approach taken in its design. The AR Receiver is as sensitive, precise and powerful a unit as is ever likely to be needed in the home. In addition, it is one of the simplest to operate; as in the best of professional equipment, control functions have been limited to those which are actually needed.

Applicable IHF test standards are used for the following guaranteed performance specifications.
Specifications
Switched Input Circuits:  magnetic Phono; Tape Playback;  Extra high-level input pair ("Special")
Outputs:  tape record;  4 - 16 Ω speakers;  headphone jack on front panel;  output to amplifier for center-channel or mono extension speakers.
FM Section
Sensitivity:  2,0 microvolts or better (hush control "off").
Signal-to-Noise Ratio:  65 dB ASA "C" weighting (flat)
Harmonic and IM Distortion (Mono or stereo):  less than 0,5%
Frequency Response:  20 to 15,000 Hz  ±1 dB (mono or stereo)
Capture ratio:  2 dB or less
Separation:  35 dB minimum at 50 Hz; 40 dB minimum at 400 Hz; 30 dB minimum at 10,000 Hz
Control Amplifier Section
Power Output (measured with both channels driven):
60 watts per channel RMS at 4 Ω
50 watts per channel RMS at 8 Ω
30 watts per channel RMS at 16 Ω
Distortion (at any level up to and including full rated power)
IM Distortion (60 and 7,000 Hz, 4:1):  less than 0,25%
Harmonic Distortion:  less than 0,5% from 20 to 20,000 Hz
Power Supply:  110 - 220 V  50/60 Hz
Dimensions (W x H x D):  16-5/8" x 5-11/16 x 11-1/8"(without cover)
With Optional wood cover:  17-1/4" x 6" x 11-1/8"

Acoustic Research Tuner

Tuner Specifications
Sensitivity:  2,0 µV or better, for 30 dB of quieting (IHFM)
Signal-to-Noise Ratio:  65 dB (ASA "C" weighting)
Distortion
IM and THD : 0,25% or less (mono)
IM and THD : 0,5% or less (stereo)
Frequency Response:  20 Hz to 15 kHz  ±1 dB (mono and stereo)
Capture ratio:  2,0 dB or less
Selectivity:  55 dB or better (alternate-channel)
AM Suppression:  55 dB or better
Spurious Response: 
Image Rejection : 70 dB or better
IF rejection : 100 dB or better
Other responses : 90 dB or better
Separations:
35 dB minimum at 50 Hz
40 dB minimum at 1 kHz
30 dB minimum at 10 kHz
Output Level:  750 mV RMS minimum for 100% modulation (at max. setting of level control)
Output Impedance:  less than 1 k Ω, will drive loads of 10 k Ω or higher


Acoustic Research Amplifier

 The AR amplifier will provide any speaker system with a signal source as accurate and powerful as is ever likely to be needed in the home. In addition, the AR amplifier offers the reliabilty and moderate price which are the objectives of every AR design.  The result is a unit which uses advanced silicon transistor technology and manufacturing and testing techniques developed by AR to achieve a level of performance comparable to or exceeding, that of the best professional recording or broadcast equipment of its type. This is shown in the technical data sheet published by AR, corroborated by independent tests such as that by CBS laboratories published in High Fidelity, and guaranteed by AR to remain correct .
 One of the most important characteristics of an amplifier is its power output. Consumers might therefore expect this measurement to be presented clearly and accurately in amplifier advertising. This has not been the case. In recent years, a variety of vague and irrelevant terms has been used by manufactures to describe power output; music power, transisor power, IHF power and others. The list includes terms invented by manufactures and applied to their products alone, as well as standards of measurement known only to advertising copy writers. In a recent issue of High Fidelity for example, 18 manufacturers advertised amplifiers, but in only two casas were power ratings referred to a known standard.
 Acoustic Research accepts the definition of a watt given in physics texts; work done at the rate of 0,7375 ft-lb/second. We know of no "music watt" or "IHF watt" which science tecognizes. AR amplifiers are rated exactly as we measure them, with both channels continuously delivering at least the rated power without exceeding our harmonic distortion limit of 0,5% or our IM distortion limit of 0,25%. The laws of physics and the nature of music require that power measurements, if they are to be meaningful, be made with a steady, uninterruptedtone, similar to the purest means. AR amplifiers must deliver their rated continous power at all frequencies to which the ear responds, non just at 1,000 Hz, where most amplifiers  can deliver much more power than at the extremes ofthe ramge of hearing. Distortion measurements are made through the AR amplifier's phono input because this is the way music goes through the amplifier - even though performance might be better with the preamplifier out of the circuit.
 For these reasons, the power output rating of the AR amplifier is true for any kind of musical tone, not only those easy for an amplifier to reproduce, whether the source is an FM broadcast a tape recording or a phonograpf record.
The workmanship and performance in normal use of the AR amplifier are guaranted for two years from the date of purchase.
 AR publishes a non-technical guide for consumers who want to know the basic facts about amplifiers, what they do and how they differ from each other. It is entitled, "You Don't Have To Be An Engineer", and is available free on request.
Specifications
Power Output:
60 watts per channel RMS at 4 Ω
50 watts per channel RMS at 8 Ω
30 watts per channel RMS at 16 Ω
Rated with both channels running at full output at 0,5% THD or less, at any frequency between 20 and 20,000 Hz.
Harmonic Distortion:  less than 0,5% from 20 - 20,000 Hz
IM Distortion (60 & 7,000 Hz , 4:1):  less than 0,25% at any listening level to full power.
Frequency Response:  20 Hz to 20,000 Hz ±1 dB (indicated flat tone control settings, at full power or below)
Switched Input Circuits:  Magnetic Phono; Tuner; Tape Playback
Outputs:  Tape record; 4 - 16 Ω speakers
Input Sensitivity/ Impedance: 
Phono : 2 mV - 5 mV/50 k Ω
Tape PB, Tuner : 200 mV/150 k Ω
Signal-to-Noise Ratio: 
Phono :  57 dB
Tape Pb, Tuner :  75 dB
Output Impedance Tape Record:  5 k Ω
Output Impedance at Speaker Terminals:  0,2 to 0,5 Ω (depending on frequency)
Damping Factor: 
8 to 20 for 4 Ω speakers
16 to 40 for 8 Ω speakers
32 to 80 for 16 Ω speakers
Safety Features:  Line fuse; speaker fuses; Circuit breakers (self-resetting)
Circuit Characteristics: 
DC Driver clamping for clean overload recovery;
Idling power supply eliminates turn-on transient noises;
Bass and treble separately controlled for each channel;
Differential loudness compensation curves in bass control circuit;
Special null circuit permits exact balancing of stereo source material;
Stable under short-circuit of speaker terminals;
Built-in null circuit provides quick accurate means for channel balancing;
Color coded input and output conectors simplify installation,.
Power Input:  110 - 220 volts  AC, 50/60 Hz
Dimensions (H x W x D):  4-5/16" x 15-1/2" x 10" (without cover);  4-1/2" x 15-3/4" x 10" (with wood cover)

Weight:  19 lbs (8,64 kg)

Luxman T-115

 PLL Frequency Synthesizer FM/AM Tuner

The sound and performance of Luxman tuners is legendary. And that legend continues with the model T-115, a highly innovative and advanced digital tuner.
The T-115 is a fully automatic tuner which utilizes Quartz PLL Frequency sysnthesizer technology for quick and accurate station selection. Instead of a conventional tuning knob, two tuning "keys" are used. The slightest touch of either key moves reception to the next higher or lower frequency. The selected station is then "locked" in position for drift-free reception.
 Manual tuning is possible by depressing the Manual Button. There's also a 12-station memory bank which provides capabilities for presetting 6 FM and 6 AM stations.
Unlike conventional memory systems, Luxman's design is immune from temperature and moisture conditions. Its stability is assured by modern integrated circuits that retrive the preset stations with accuracy.
The sound of the new T-115 is pure Luxman; clean and distortion-free. And its attractive faceplTE, WITH Digital Indicator, amkes the Lixman T-115 a beautiful addition to any stereo system.
Specifications
FM Section
Usable Sensitivity:  10,3 dBf (1,8 µV)
50 dB Quieting Sensitivity:  15,6 dBf (3,3 µV)
S/N Ratio at 65 dBf:  76 dB
Frequency Response:  30 Hz -15 kHz (-1 dB)
Distortion at 65 dBf (Mono / Stereo):
100 Hz : 0,12% / 0,3%
1 kHz : 0,15% / 0,3%
6 kHz : 0,2% / 0,4%
Capture Ratio at 65 dBf:  1,4 dB
Adjacent Channel Selectivity:  10 dB
Alternate Channel Selectivity:  75 dB (± 400 dB)
Spurious Response Ratio:  85 dB
IF Response Ratio:  85 dB
Image Response Ratio:  70 dB
AM Suppression Ratio:  56 dB
Stereo Separation (Mono / Stereo):
100 Hz : 56 dB /40 dB
1 kHz : -/ 45 dB
10 kHz : - / 39 dB
Subcarrier Product Ratio:  62 dB
SCA Rejection ratio:  60 dB
Muting Threshold:  10 µV - 300 mV (Variable)
Output Level:  800 mV
AM Section
Usable Sensitivity at 1 MHz, (400 Hz 30% mod.):  200 µV/m
Image Response Ratio at 1 MHz:  50 dB
IF Response Ratio at 1 MHz:  40 dB
S/N Ratio at 1 MHz (10 mV/m, 400 Hz 30% mod.):  50 dB
Distortion at 1 MHz, (10 mV/m, 400 Hz 30% mod.):  0,5%
General
Power Consumption:  10 W
Dimensions (W x D x H):  438 x 312 x 85 mm (17-¼" x 12-9/32" x 3-11/32")

Weight:  5 kg (11 lbs)

Luxman K-117

 High Capability Dolby / Metal Cassette Deck

The Luxman K-117 cassette deck incorporates the most modern and desirable features of contemporary cassette deck design. In keeping with the long-standing Luxman reputation in tape deck technology, it affords the discriminating listener accurate sound reproduction that's true to the music.
The K-117 is fully compatible with metal particle tapes, and it has been thoroughly engineered to make full use of their extended high frequency response and wider dynamic range. It also accepts chromium and normal bias tapes and features Dolby circuitry.
The K-117 also offers some unique features of its own.
 A bias Fine Control, operated from the front panel, lets you alter bias current within ±15% from the nominal (average) bias point. In effect, it gives you the freedom to subtly alter the frequency response for any given tape.
Instead of VU meters, the K-117 utilizes a fluorescent peak level indicator for quick response to the recorded signal. To help you handle the extended dynamic range of metal tapes, the indicator has provisions for an additional 3 dB of level which becomes up to +8 dB.
Tape movement is activated by logic/solenoid feather-touch controls, for which an optional remote control box is available. An auto-repeat function automatically rewinds the tape at its end and repeats play.
Of course, it's the sound of the Luxman K-117 that really counts. And that's how it sounds. Like a Luxman. Free of audible distortion, full range, and accurate.
Specifications
Type:  2-head, single compact cassette deck
Track System: 4-track, 2-channel stereo
Tape Speed: 4.75 cm/s
Heads:
1 Hexalam recording / reproducing head;
1 double gap ferrite erase head
Harmonic Distortion:  less than0,7%
Frequency Response:
Metal Type : 20 - 20,000 Hz
CrO₂ Type : 20 -18,000 Hz
Wow and Flutter (WRMS):  less than 0,06%
Signal-to-Noise Ratio:
CrO₂ with Dolby : 62 dB
CrO₂ without Dolby : 57 dB
Input Sensitivity:
Line : 100 mV
Microphone : 0,3 mV
Output Level
Line : 500 mV
Headphones : 1 mW
Dimensions (W x H x D):  438 x 109 x 275 mm

Weight:  5 kg

B&W 201i

 B&W's loudspeakers have long been revered throughout the world by respected audio critics and the professional recording industry alike.  In fact, the acoustic qualities of all loudspeakers have endeared it to more audiophiles over the many years than any other high-end loudspeaker.
Now, we've taken evertything we've learned about the behavior of dynamic loudspeakers and applied it to a series of affordable loudspeakers that are nothing short of remarkable. The application of this knowledge, combined with innovations in driver technology and crossover design, have created two new loudspeakers that provide surprising musical realism and movie soundtrack excitement.

Both the 201i and 202i feature new bass/midrange drivers. For consistent performance, regardless of amplitude, frequency or temperature, these drivers use high temperature voice coils wound on glass reinforced Kapton formers. Special PVC compounds terminate the fibre cones for resonance-free bass fundamentals. High sensitivity tweeters ensure sparkling high frequency response beyond the limits of audibility with liquid cooling for high power handling.  The result is remarkable bass extension and absence of unwanted resonances, particulary in the critical midrange frequencies.

Using B&W's proprietary computer aided crossover optimization program, the frequency dividing networks have been fine tuned for a degree of three-dimensional spatial imaging unheard of in such affordable loudspeakers. The 200i Series enclosures, designed by Kenneth Grange, feature wedgeshaped grilles on acoustically transparent frames to minimize diffraction. With superb visual style,  captivating audio performance, and a surpisingly attractive price, the 201i and 202i carry the B&W tradition into a new arena.
 B&W 201i
Stand-mount/Bookshelf loudspeaker system
Product Summary
The 200 series was deemed as the rarity in the mass consumer hi-fi market – a reasonably priced loudspeaker that provided high sensitivity, extended linear frequency response and pinpoint stereo imaging.
The 201i is a 2-way vented box loudspeaker system. The speaker comprises of a 1in high frequency unit with polyester dome and one 6-in low/mid frequency composite fibre cone.
The B&W wall bracket accessory permits easy, multi-directional positioning on walls.

Technical highlights
The Design incorporates a cabinet profile and wedge shaped grilles on acoustically transparent frames.
The magnetic fluid-cooled voice coils are a B&W hallmark, wound on glass reinforced Kapton® formers, enabling the drivers to take the heat when reproducing modern digital recordings.
In common with all B&W tweeters, the lightweight units incorporate low viscosity magnetic fluids to offer excellent power handling and linearity.
Specifications
Drive Units: 
1 x 25 mm high-frequency with polyester dome
1 x 165 mm low frequency with composite short fibre cone
Frequency Response:  66 Hz – 20 kHz ±3 dB on reference axis
Sensitivity:  90 dB spl(2.83V 1m)
Nominal Impedance:  4 Ω
Power Handling:  Suitable for amplifiers up to 100 W Continuous
Dimensions (H x W x D):  Height: 360 x 225 x 181mm

Finish:  Black ash vinyl

B&W 202i

 B&W 202i
Stand-mount/Bookshelf loudspeaker system
Product Summary
 The 200 series was deemed as the rarity in the mass consumer hi-fi market – a reasonably priced loudspeaker that provided high sensitivity, extended linear frequency response and pinpoint stereo imaging.
 The 202i loudspeaker system is a fourth-order vented loudspeaker system. The speaker comprises of a 3/4 -in high frequency with a polyamide dome and one 7in low frequency polypropylene cone.
 The B&W wall bracket accessory permits easy, multi-directional positioning on walls.

 Technical highlights
 The Design incorporates a cabinet profile and wedge shaped grilles on acoustically transparent frames.
 The magnetic fluid-cooled voice coils are a B&W hallmark, wound on glass reinforced Kapton® formers, enabling the drivers to take the heat when reproducing modern digital recordings.
 In common with B&W tweeters, the lightweight units incorporate low viscosity magnetic fluids to offer excellent power handling and linearity.

Specifications
Drive Units: 
1 x 19 mm high-frequency with polyester dome
1 x 180 mm low frequency with composite short fibre cone
Frequency Response:  48 Hz – 20 kHz ±3 dB on reference axis
Sensitivity:  90 dB spl(2.83V 1m)
Nominal Impedance:  4 Ω
Power Handling:  Suitable for amplifiers up to 120 W Continuous
Dimensions (H x W x D):  Height: 497 x 225 x 222mm

Finish:  Black ash vinyl

Koss ESP-9

 Koss ESP-9 Electrostatic Studio Monitor
Offers a new tool for improved audiometry with self-bias or ac line energizing. Controlled monitoring with 1 octaves ±2 dB range exceeding best loudspeaker systems.  Eliminates all room reflections and polar distribution problems.
 Super wide-range response -  for critical, controlled monitoring of finest recording sources. Delivers all 10 audible octaves, 10 - 19,000 Hz (±5 dB), 4 octaves beyond ordinary headphones.
Virtually distortion-free performance -  precision electrical balancing of push-pull acoustical circuitry to give fatigue-free listening through long, intense recording sessions. Elements cancel all 2nd harmonic distortion, unlike conventional units.
Lightweight - human engineered for comfort - uses fluid-filled cushions for good, comfortable seal; extendable stainless steel headband with wide cushion for perfect fit and restful listening.
Calibrated, precisely controlled output - ideal for audiometric uses - switch on front panel of energizer selects ac operation for precision measurements of output; in self-energized switch position no connection to ac lines is required; this gives maximum convenience.
 High-power capability in very low bass range - lerge, oversize coupling transformers mounted in external E-9 energizer unit give good wave form at 30 Hz with up to 10 volts input.
No special amplifiers required - low efficiency, connects to low-impedance speaker terminals - easy, quic hook-up to any rated high-quality amplifier delivers performance to specification. Excellent for evaluating the spectral character of very low level noise in equipment like tape mastering machines and recording consoles. In contrast to the ESP-6 and ESP-7, both cups are independently energized; al. Eft cup signal in not required to supply bias to the right cup.
 E-9 Energizer:  Contains 2 coupling transformers, self-energizing circuitry, speaker/headphone transfer key-switch and ac pilot light on black anodized front panel Also contains ac power transformers, ac on-off switch, ac line fuse, and speaker terminals.  Has 6'4" conductor input cable terminated with 4 spade lugs to connect to amp. output terminals.
Size:  4 ½ H x 3 ¾ W x 6 ¼ D inches
Weight:  3 pounds
Specifications
Electrical
Frequency Response Range, Typical:  15 -15,000 Hz ±2 dB (10 octaves) 10 - 19,000 Hz ±5 dB
Sensitivity:  80 dB SPL at 1 kHz ±1 dB reffered to 0,0002 dynes/cm² with 1 volt at the input
Total Harmonic Distortion:  less than 2% at 110 dB SPL
Isolation from External Noise:  40 dB average through fluid-filled cushions
Power Handling Capability:  Max. Continous program material should not exceed 10 volts (12 watts) as read by an ac VTVM (Ballantine meter 310B or equal) with average indicating circuitry and rms calibrated scale, provides for transient peaks 14 dB beyond the continuous level of 10 volts
Source impedance: Designed to work from 4 to 16 Ω amplifier outputs
External Power Requirements:  None, except when external ac line is selected on front panel switch of the E-9 Energizer (1/16 amp. 117 VAC, 50/60 Hz normally; 234 VAC with internal strap for foreign use)
Physical
Size of Cup:  4 ¼" H x 3 ¾" W x 1 ¼" D
Cushions:  Fluid-filled for high ambient noise isolation
Headband:  Extendable stainless steel bands with self-adjusting pivoting yokes; conforms to any head size
Boom Mount for Microphone:  Knurled, anodized aluminum knob on left cup with threaded shaft and 2 compressible rubber washers; accepts all standard booms
Headset Cable:  Flexible, polyvininyl, 5 conductor shielded. 6" long, black with 5 prong plug keyrd to E-9 Energizer receptacle
Weight of Headset Only:  19 ounces

Accessory provided:  6" ac line-cord P.N 41-0235 for optional use

Koss ESP-6

 Koss model ESP-6 Electrostatic stereophones
Break through in design gives distortion free, wide-range frequency response. Never before possible in headphones.
 3 octaves of sound beyond the limits of ordinary coil and cone type driver elements - this wide range is reachable only through electrostatic.
World's first Self-Energized Electrostatics - easy to use you just plug-in like other headphones. No special amplifiers or power supplies needed.
Virtually Distortion-free, because of push-pull operation, Elements cancel all 2nd harmonic distortion, unlike ordinary units. Square waves can be reproduced for the first time by an electro-acoustic-reproducer.
Dynamic level Indicators give measure of level - flicer at 10th row full orchestral volume, stay lit at very high levels.
Calibrated Machine-Run Frequency response, Chart with each headset - positive guarantee that the headset you buy meets specifications.
Cleaner, Wider range response than the best loudspeaker system yet producer - for the first time you hear what really comes out of the tape machine, disc reproducer, radio-tuner or microphone.
 Through the development of the world's first self-energized and self-contained electrostatic headphones, a true breakthrough in wide-frequency response-range and low distortion has been achieved  by Koss physicists and scientists.   Reproduces 9 of 10 audible octaves. This wide range is reachable only through electrostatic stereophones. Exceeding performance of the best loudspeaker systems now available, you get a critical monitoring facility that tells you exactly what comes out of professional recording or monitoring equipment.  A new era in personal listening is now available to the discriminating  music-lover at 10% of the price of the finest loudspeakers, you get sound as originally recorded, without lost stereo from wall and ceiling reflections. Spurious room resonances are banished because of the controlled listening environment tailored exactly to the human ear.
Frequency response is 30 to 19,000 Hz (±5 dB). Model ESP-6 complete with 10' coiled cord and connector box T-3.
Koss T-3
Speaker - headphone transfer switch
The T-3 is designed to provide a means of switching from stereo speakers to Stereophones. It is connected to the speaker terminals of the amplifier or receiver. The T-3 should be used when the headphone jacks on the amplifier or receiver has high value resistors in series with it. These violently alter the normal 8 Ω impedance upward. The high impedance which results prevents high quality, low impedance headphones from delivering wide range performance.

The T-3 can be used with any amplifier having 4, 8 or 16 Ω output taps.