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

STAX SR-Λ (Lambda) Series

 The SR-Λ (Lambda) series have such pleasing sound quality because its diaphragm is oblong, instead of round, as in the SR-Σ Series. This shape approximates the elliptical shape of the outer ear so that you use your entire ear to listen to the sound, just as you would in a natural listening situation. In fact, the diaphragm is actually larger than the average ear's dimensions to take full advantage of the outer ear's response characteristics. The result is fuller low range response along with the uncolored mid and high range response typical of electrostatic reproduction.
The design approach of the SR-Λ Series won various prizes and especially the SR-Λ Signature is called "The best Headphone in the World".
 SR-Λ (Lambda) Normal + SRD-7sb
Stax introduced the SR-Lambda in 1979. still a worthy product in its own right, it has also served as the foundation for the most important earspeaker innovations since then. And in one respect it has not yet been bettered - the earpiece.  This designencloses the outer ear, housing an angled oblong diaphragm larger than the average ear's dimensions. The radiated sound is then captured by all parts of the outer ear and conducted to the eardrum - just like listening in any normal situation. The brain perceives a spacious sound field outside the listener's head. How unlike the typical headphone, whose earpiece crushes the outer ear, not permitting it to do its job, while the small dynamic speaker injects the music unnaturally into the ear canal.
SR-Λ (Lambda) Professional

Daimler Benz provided the impetus for the SR-Lambda Professional (1982) when they requested a unique earspeaker to analyze car noise. Stax achieved the desired low-frequency response by increasing the electrode gap and the polarizing voltage. These changes also created side benefits - the Lambda could now play louder than before, and with increased efficiency and less distortion. Until the advent of the Signature, the SR-Lambda Pro was the best earspeaker Stax  knew how to make; it remains a product second  to one only.

 The SRM-1 Mk2 Professional was designed to drive the SR-Lambda Pro or other earspeakers dirctly. Its pure class-A circuit eliminates audio transformers and coupling capacitors for detailed, natual reproduction. Like the SRM-T1, this unit can be connected to the tape loop of a preamplifier, or run directly from the line-level source - CD player, tape deck, tuner or mixing console - resulting in a remarkably simple and elegant signal path. It has output sockets for one Professional Series and one standard earspeaker.
 The SR-Lambda pro earspeaker can also be powered through the SRD-P portable energizing adaptor. It employs high-power IC's and Professional bias-voltage circuitry to extract the earspeaker's capabilities. The SRD-P operates not only on a household power source but also on batteries, allowing remote use for high-quality monitoring of location recordings. Its RCA input trminals enable direct connection to line-level outputs (as with the SRM-1 Mk2 Pro); but it also has a mini-jack input for use with portable cassette decks or mini CD players.
The SRD-7 Professional energizing adaptor connects to the speaker taps of a power amplifier, enabling one to enjoy Professional Series earspeakers  over whatever equipment one already owns. It contains advanced features like LC-OFC wiring and audio transformer windings, and an all-aluminum chassis to eliminate magnetic distortion. This adaptor is a particulary viable alternative to the direct-drive earspeaker amplifiers if one has made a major investment in state-of-the-art. Preamps and power amps.
SR-Λ (Lambda) Signature + SRM-T1
Surpassing the SR-Lambda Pro - probably the most widely acclaimed audio component of recent years - was a formidable task, but that is what the SR-Lambda Signature has accomplished; any superlatives not expended on the Lambda pro may now be safely employed. Two material changes are largely responsible. The Signature's transducing diaphragm is only one micron thick, a reduction of one-third from the Lambda Pro. And the signal cord is made of PC-OCC cable, specially cast from oxygen-free copper to preserve phase integrity through large linear-crystal-line structure.
A standard-setting earspeaker requires an amplifier which performs similalry - the SRM-T1.  this two-stage driver unit incorporates dual FET's and twin 6FQ7/6CG7 triode output tubes, thus combining transient speed with the smoothness and dimensionality sophisticated audiophiles have come to expect from vacuum-tube amplification. The SRM-T1 can accommodate both Pro Series and normal earspeakers.
The Signature System is urgently recommended for discerming audiophiles seeking the ultimate in musical information retrieval.
SRM-T1 Tube Driver 
Frequency ResponseDC-20kHz, +/-1dB
Gain:  60 dB
Harmonic Distortion:  0,02%
Input Impedance:  50 k Ω
Input Level:  100 mV
Maximum Output Voltage:  330 V RMS (1 kHz)
Bias Voltage:  230 V DC, 580 V DC
Power Requirements:  100 - 240 V 50/60 Hz
Dimensions (W x D  x H):  7-3/4" x 15-1/4" x 4"
Original Box (W x D x H): 18" x 9-1/2" x 5"  (+1 lbs)
Weight:  10,5 lbs

STAX SR-Λ (Lambda) Signature

 Above fifthy five years ago (1959), Stax became the first company in the world to develop and manufacture Electrostatic Headphone, "Earspeaker". Today, our experience is making a dramatic difference  that you can enjoy. For example, Daimler-Benz was so taken with "Stax technology" that they requested  a special earspeaker to test the acoustic environment in their limousines. This earspeaker became well-known as the SR-Λ Professional. Now, the SR-Λ Signature is the successor to the SR-Λ Professional. It is constructed of select materials and is hand assembled to meet the superlative standard of Mr. Naotake Hayashi, the president and founder of Stax.
Stax is proud to have created a new reference standard for earspeakers that obtains an even higher level of performance than the SR-Λ Professional. The Signature series SR-Λ uses a transducing diaphragm made of high-polymer that is only "one" micron thick. The signal cord is made of PC-OCC cable that is specialy cast from pure copper to preserve phase integrity through large linear crystalline structure.
 The SR-Λ Signature  is designed to operate at 580 V D.C. bias.it can be used with any Stax professional adaptor or direct drive amplifier. The SRD-7/Mk2 and the SRD-7sb/Mk2 are adaptors that enable the SR-Λ Signature and normal-bias earspeakers to work in conjunction with any high quality amplifier or receiver. The SRD-7/Professional is an adapter that enables two SR-Λ Signature  earspeaker (or two other pro-bias earspeakers) simultaneously to work in conjunction with a high quality amplifier or receiver. The SRD-X/Pro and the SRD-P are portable adaptors.  They allow the use of the SR-Λ Signature  in remote locations. The SRM-1/Mk2 Pro is a Class-A DC direct drive amplifier for any Stax earspeaker. The SRM-T1 is a Hybrid FET/vacum tube direct drive amplifier that is Specifically designed to highlight the SR-Λ Signature . It also will drive any Stax earspeakers.
Type:  Push-pull Electrostatic Oval Shape Units. Open back Enclosure
Frequency Response:  7 - 41,000 Hz
Electrostatic Capacity:  122 pF (including cord)
Impedance:  129 k Ω / 10 kHz
Sensitivity:  101 dB / 100 V RMS (input/ 1 kHz)
Maximum Output Sound level:  118 dB / 400 Hz
Bias Voltage:  580 V D.C. (standard)
Indication of Left/Right Channel:  Left [L]and Right [R] indicated at headband slides, and a solid line [L] & a broken line [R] on the cable
Ear Pads:   High quality soft vinyl leather
Cord:  6-core parallel low capacity wire/ full length 2,5 m [PC-OCC Continuous Crystal Copper]
Weight:  450 g (322 g without cord)

STAX SR-Λ (Lambda) Nova

 The Lambda Nova Series were designed for the person who loves the sound of the recent SR-Lambda Series but needs more modern sofisticated design. We put new shaped head-spring together with new sound units. As a result, the frequency responce was flattened and the wear confort was refined. The Lambda Nova Series carry the superiority of the former SR-Lambda Series and further more add special merit of new sound unit and head spring.
 The Lambda-Nova Series earspeaker is the fruit of the most up-to-date technology and many-years of experience of Stax that first developed and manufactured the electrostatic headphone, that is the first "earspeaker", in the world.
Differently from ordinary headphones, this earspeaker is equipped with neither magnet nor coil, but utilizes electrostatic force to generate sophisticated sound. In detail, the core of an earspeaker is composed of a thin diaphragm (oscillatory film) to which a DC voltage of 580 V is supplied. When audio signal is supplied to the electrodes, an electrostatic force is generated that drives the diaphragm to reproduce the sound. Thanks to this operation principle, the earspeaker reproduces sound very naturally and delicately in all nuances.
The Lambda-Nova Series earspeakers are advanced products of the SR-Λ series that has continuously been improved for more than 15-years.
For upgrading the electrostatic transducer, Stax improved not only the processing precision  of the thin diaphragm that has had an established reputation but also the structure of the electrodes to receive the audio signal. This, with the first rate technology cultivated through the manufacturing experience of the SR-Ω series.  As a result, Stax offers this earspeaker equipped with high quality transducers that are superior to others in sound clarity and excellent reproduction in detail at all levels.
 Most earspeakers made by Stax are designed to operate with the pro bias voltage (580 V/DC). The lambda-Nova series earspeakers also work with the pro bias voltage, however, Stax's old type earspeakers such as the model SR-1 that was put on the market in 1960 for the first time were designed to operate with the Normal bias voltage (230 V/DC). These two types of earspeakers can be discriminated from each other by the number of pins on the connector cord plug.  Namely, earspeakers whose connector plug has 6-pins are designed to use with the Normal bias voltage, while earspeakers whose connector plug has 5-pins are designed to use with the pro bias voltage.needless to say, the 5-pin connector of the Lambda-Nova series earspeakers should be plugged into a connector jack that has 5 pinholes and is usually identified with the indication of "Pro Only". If the lambda-Nova earspeakers is connected to a 6-pinhole jack for Normal bias, the result will be low volume and soft sound.
Type:  Push-pull Electrostatic Oval Shaped Units, Open Back Enclosure
Frequency Response:  7 - 41,000 Hz
Electrostatic Capacity (including cable provided respectively):
Lambda-Nova Basic, lambda-Nova Classic : 120 pF
Lambda-Nova Signature :  110 pF
Impedance (10 kHz including cable provided respectively)
Lambda-Nova Basic, Lambda-Nova Classic :  133 k Ω
Lambda-Nova Signature :  145 k Ω
Sensitivity:  100 dB / 100 V RMS, Input 1 kHz
Maximum Output Sound Level:  118 dB / 400 Hz
Standard Bias Voltage:  580 V/DC
Left/Right Indication:  L & R indicators are provided on the Head Spring (Arc) and the left channel cable is marked with a solid line while the right channel cable is marked with a dotted line
Ear pads:  High quality synthetic leather
Cable:  6-core parallel low capacitance wire. 2,5 m (98-inch). Special low capacitance Cable; Lambda-Nova Signature
Cable Conductor:
Lambda-Nova Basic :  OFC
Lambda-Nova Classic, Lambda-Nova Signature :  PC-OCC (Pure Crystal  Ohno Continuous Casting)
Lambda-Nova Basic, Lambda-Nova Classic :  440 g
Lambda-Nova Signature :  472 g

Body Only (without cable):  295 g

STAX SR-Σ (Sigma) Series

 Stax electrostatic earspeakers are widely used by the best recording studios and broadcast stations in the world. The simple reason for this is that these earspeakers deliver unsurpassed sound quality and the most accurate high fidelity reproduction possible. The general advantages of headphones over speaker systems are:
The acoustic conditions of the listening room do not affect the sound.
The diaphragms do not have to move much air (there is little load) therefore they can be made lighter to improve transient response.
There is no danger of acoustic feedback (howling) to the turntable.
The diaphragms are very close to the ears, so it is easy to pick up small musical details.
 The advantages of electrostatics over conventional headphones are:
The several micron thick high polymer film diaphragm is so light that it can respond accurately and instantaneously to the tiniest signal fluctuations.
There is no magnetic (hysteresis) distortion since no magnets or voice coils are used.
Electrostatic drive ensures uniform control over the entire diaphragm surface so there is no partial vibration or the cone breakup seen in dynamic type headphones.
 Stax (SR-Σ) Professional Series
The Stax professional series earspeakers have originally been developed for Daimler-Benz, the world-famous West German automotive manufacturer. They feature a wider electrode gap realized by a increased bias voltage (580 V). This resulted in a distortion-free bass sound along with a incredibly pure mid and high frequency range.
 The SR-Σ (Sigma) and Σ Professional are completely new kind of earspeakers developed over a long four year period. Their innovative design lets you enjoy more natural ambience reproduction than is possible with simple headphones. The diaphragms are placed forward away from in a normal music listening environment. The outer ear is not pressed, so the entire ear interacts naturally with the sound. Furthermore, a carefully designed cavity is employed to produce resonance characteristics simulating those occuring in a hall or room. All this results in a panoramic sound field without the feeling one has with conventional headphones that the sound is centered within one's own head. The employment of comfortable lightweight materials and a biomechanically engineered headband also contributes to the non-fatiguing pleasure of listening to music with the SR-Σ and SR-Σ Professional.
Stax SR-Σ (Sigma) System -
The Stax SR-Σ Panoramic Imaging Electrostatic Earspeaker design is a successful attempt to recreaqte a natural, realistic sound field from a headphone format. Headphones were originally designed for picking up Morse Code in communications, not recreating a musical sound stage. Until the introduction of the Stax SR-Σ, no headphone manufacturer paid much attention to ambience and its effect on musical imaging.

The SR-Σ earspeaker design locates an oval shaped electrostatic transducer in front of the ear at 90° angle to the ear. This does two things to improve the image perspective to the listener. First, by using an oval shaped transducer that is larger than the outer ear itself, the SR-Σ allows the outer ear to naturally channel the waveform into the inner ear. This allows the sound to reach the eardrum in the most conventional way. Second, the transducer is located in front of the ear, not over the ear. This removes the image perspective from within the listener's head and places the image in front of the listener. The SR-Σ transducing elements are positioned ideally in terms of the natural perimeters and auditory path of the ear. The result is optimum spacing for music in relation to the ear. The SR-Σ gives natural sound with none of the tight, sealed-in feeling, or the diminished scale sensaations conveyed by ordinary headphones.
Specifications SR-Σ [SR-Σ Professional]
Type:  Electrostatic / Push-pull High Bias
Frequency Response:  25 - 38,000 Hz [30 -35,000 Hz]
Sensitivity:  94 dB [98 dB]
Impedance (10 kHz):  122 k Ω [143 k Ω]
Maximum Output:  103 dB
Earpad:  Soft artificial leather, replaceable
Cord (low-capacitance):  2,5 m; 6-strand  6-pin plug [5-pin plug, PC-OCC]
Weight (without cord):  391 g [395 g]

STAX SR-Γ (Gamma) Series

 The SR-Γ (Gamma) and SR-Γ pro New are improved model of the original Model SR-5N. It offers the proven life-like sound qualities and performance of SR-5N Earspeaker and feature a new cage grid frame constraction. Thanks to the world's thinnest diaphragm, fashioned out of a high-moleculer film 2.0 (1.5 for Pro) micron thick, the SR-Γand SR-Γ Pro New achieve superb transient and uncomparable mid and high transparency.
  The new cage grid design gives full play to all the performance potential of the earspeakers and contributes to the light-weight, comfortable fit that will definitly enhance your listening pleasure. Stax SR-Γ professional has been improved incorporating newly designed ear pad. With this ear-pad, SR-Γ Pro's low frequency reproduction ability has been tremendously made rich.
 The standard SR-Γ earspeaker first appeared in 1985. its transducing diaphragm is two microns-thick, providing superior transient attack. It is supplied with the SRD-6sb energizing adaptor, which attaches to the output of a power amplifier. This adaptor is self-biasing (deriving its power from the audio signal itself); no AC power is required, thus granting the user greater flexibility regarding its placement.
Stax SR-Γ Professional specifically designed for the American market, the SR-Gamma earspeaker models occupy a price plateau below that of the Lambda products; since the Gammas utilize the same advanced technology and claim many of the same sonic attributes,, they constitute a genuine bargain. Their open-type oval enclosures prsent a clear, balanced sound field uncolored by cavity resonances or reflections.  The Gamma Professional contains the 1,5 micron-thick diaphragm and increased electrode gap and bias voltage found in the SR-lambda pro. It comes with the SRD-7 Professional energizing adaptor.
Specifications SR-Γ [SR-Γ Professional]
Type:  Electrostatic / Push-pull High Bias
Frequency Response:  15 - 30,000 Hz [15 -40,000 Hz]
Sensitivity:  103 dB
Impedance (10 kHz):  120 k Ω [140 k Ω]
Earpad:  Soft artificial leather, replaceable [large size]
Cord (low-capacitance):  OFC 2,5 m; 6-strand  6-pin plug [5-pin plug]

Weight (without cord):  190 g [192 g]

STAX History of Earspeakers

Stax Industries, Ltd, is japan's oldest and most honored manufacturer of specialized audio equipment. In 1959 Stax developed the world's first electrostatic headphone - marketed the following year as the SR-1.  [Today] Thirty years later, president Naotake Hayashi and his son Takeshi Hayashi continue their tradition by offering the finest headphones for both professional and audiophile applications. Stax prefers to call its headphones "Earspeakers"; such Ultra-High Fidelity devices for reproducing music can only be compared with the best cost-no-object loudspeakers, not other headphones. The term "Earspeaker" is therefore more descriptive of Stax's contribution to today's most advanced level of sonic transduction.

The Stax philosophy revolves around a single tent; the more precisely the reproduction mirrors the original live sound, the more clearly one may grasp the soul of the musical composition and performance. With this belief constantly in mind, Stax strives to make products providing the highest performance, reliability and value.

The most advancedd product of the Stax Industries, are:
Stax SR-Γ Series (Pro);
Stax SR-Σ Series (Pro);
Stax SR-Λ Series (Professional and Signature);

And SR-X, SR-5, SR-84 or SR-34

How Electrostatic Earspeaker Works
If we speak of a headphone, it usually means a dynamic one employing a dynamic transducer. In the dynamic transducer the driving force is applied only to the one part of the diaphragm which, therefore, must be stiff enough not to be deformed by air load. However, stiff materials considerably increase the diaphragm mass resulting in significant deterioration of transient response. In addition, the ununiform force applied over the diaphragm area leads to ehat is called "cone break-up". Hysteresis distortion caused through the magnet inevitable in the dynamic transducer cannot be ignored, either.

The electrostatic transducer adopted in the Stax earspeakers consist of two parallel-arranged fixed electrodes and several microns thick (2 microns in the SR-Sigma, the SR-lambda,the SR-X/Mk3 and the SR-5N. 6 microns in the SR-84 and the SR-34) high-polymer film diaphragm suspended in the middle of the electrodes. The low-mass film diaphragm is supplied with the biasing voltage from the energizing adaptors or from the SRM-1/Mk2. In the electret type earspeakers like  the SR-84 and the SR-34 the diaphragm is permanently charged minus. When the fluctuating voltage of the audio signal is applied to the electrodes, the diaphragm is pulled by the electrode which has the opposite charge of the diaphragm's and simultaneously pushed by the other electrode which then has the like charge of the diaphragm's. the continuous flow of alternating voltage in interpretation of audio signals causes the diaphragm to vibrate in faithful compliance with the amplifier output without time lag, assuring undistorted sound waves. This is why the Stax electrostatic earspeakers sound so good. The figure above shows the driving mechanism of the SR-84 and the SR-34.

Infinity RS II

 Infinity Reference Standard II - A less expensive version of the worlds most accurate speaker.

Since its inception, Infinity has been setting new standards of accuracy in music reproduction. Its speakers are designed to, as closely as possible, translate acoustic theory into practical reality.
There are two theoretically ideal ways of propagating sound in a room environment; the line source and the point source.

The Infinity Reference Standard, introduced in 1980 as a nocompromise state-of-the-art. Speaker system, approximates line source propagation, in which the sound source must be infinitely long vertically.
The vertical dimensions of the Infinity RS is nearly equal to the vetical dimension of most rooms, approximating ideal line source conditions in a closed environment. Horizontally, the driver is so narrow at all frequencies in the audio band that its audio dispersion is essentially complete.
Now we are pleased to announce the Reference Standard II, a practical simulation of point source theory.
A true point source would be an infinitely small, pulsating sphere, with all frequencies radiating equally in all directions.
In the Reference Standard II, point source technology is simulated by decreasing the size of the radiating area as the frequency increases.  Thus, the source is always small compared to the wave length of the sound being radiated.
The Referency Standard II inherits some of its design configuration and technologies directly from the Infinity Reference Standard. However, its price, unlike the the $20,000 IRS, is affordable to most serious audiophiles.
Its diffraction wing design and dipole drivers in the high and mid-frequencies create an arresting depth, breadth and clarity of musical image.  Its dual 10" woofers in a new Infinity/Watkins woofer/subwoofer configuration are in their own enclosures, and incorporate rool-offs at different crossover points. This yeilds deep strong bass, as well as exceptional tautness and clarity in the midbass.
 Diffraction wings and what they do.
The elegant curve of the reference Standard II enclosure wings is precisely calculated to minimize the distortion caused by diffraction.
In an ordinary speaker sound waves propegated by the drivers bounce off the front of the enclosure. These diffracted waves interfere with the principal wave, causing cancellation "dead spots" in the listening room, and out-of-phase distortion.
As a result, the music is blurred and sounds muffled; the stereo image is cinfused, inconsistent, or absent altogether, depending upon one's listening position in the room.
As with the $20,000 Infinity Reference Standard, the Reference Standard II diffrection wings are mathetically curved so that the diffraction effect is minimized. The small portion of the sound waves which is diffracted  is propagated to the sides and back. Cancellation "dead spots" and out-of-phase phenomena are effectively eliminated from the listening area.
This creates an illusion of the three dimensional imaging so accurate the listener can "place" every instrument in the orchestra; front to rear, as well as left to right.
For example, Pink Floyd's "The Wall" side 1, reveals a panorama of sound with breathtaking impact.  As the distant helicopter approaches and lands, it seems to travel through the top to the bottom of the speaker; you almost feel the wind from the chopper blades as it taxis past. The children's voices, their English accents clearly discernable as they sing. Are heard, not on a single plane, but in layer after layer of sound, clearly defined in space.
 The Two Woofers
Two ten-inch woofers in the RS II are identical - yet they are used independently. Although they both operate in the very lowest bass ranges, one rolls off at 60 Hz, the other at 125 Hz.
This is a new embodiment of the Infinity/Watkins principle; instead of two voice coils on one woofer, there are two woofers operating together at certain frequencies, yet rolling off independently.
The two woofers - each in its own enclosure - are mounted in a special master enclosure of oak vener, suspended within the diffraction wing and stepped forward to assure precise phase relationship with the other drivers.
The Three Midrange Drivers.
The three five-inch midrange drivers are dipoled by leaving their backs open, allowing the back wave to complete the point source radiation pattern.
Employing a unique arrangement, the midranges crossover at two different frequencies. The upper most and the lowest operate up to 1500 Hz, while the central midrange works up to 3 kHz.
From a technical point of view, this produces distinct advantages.
Better midrange coupling is achieved in the critical lower midrange area. And, by spreading out the crossover frequencies, response is made uniform and the directivity index is made to correspond to point source radiation within the range of utilization of each separate driver.
 Polypropylene cones; the advantages are obvious.
Although much has been written sbout the many advantages of polypropylene over paper cones, and cones of exotic materials, its advantages are clearly evident upon first hearing.
This extremely light, yet very stiff material with no intrinsic sound of its own, responds uniformly and instantly to the input signal, producing music that is astonishingly clear and accurate.
It is impervious to heat, moisture and the wear and tear that shortens the life of traditional cone materials.
Polypropylene cones are used in the woofer and midrange drivers of the Reference Standars II, as they are throughout the Infinity RS series speakers.
Present Perfect.Future Positive.
Our design objective for the reference Standard II was to utilize audio technology developed for the massive Infinity Reference Standard to create a much smaller, much less expensive speaker system -  a system more technologycally advanced, more aesthetically appealing in its price range than any other speaker available.
We hope you find the RS II a profitable investment in pleasure; and an enhancement to the quality of your life - for a good many years to come.
 The Two EMIT tweeters.
The EMIT electromagnetic induction tweeters found in the RS II are considered the state-of-the-art. Tweeter by critics the world over.
EMIT, with its powerful samarium-cobalt magnets and an almost zeromas etched planar diaphragm, is unique in its ability to combine exceptional powerhandling capability with extreme delicacy - through a superauditory 32 kHz.
The Reference Standard II has two EMIT tweeters configured in a dipole pattern; one firing forward and the other facing the rear.
It should be noted that EMIT tweeters are used, in varying configurations, in every Infinity Reference Standard  and RS series speaker.
Frequency Response:  36 -32,000 Hz ±2 dB
Sugested for use with Amplifier  of:  35 - 250 watts per channel RMS
Drivers (each channel):
Woofers:  Two 10" (25 cm) with polypropylene cones in Infinity/Watkins dual-drive configuration.
Midrange:  Three 5" dipole drivers with polypropylene cones in dipole configuration.
Tweeters:  Two EMIT, one of them facing rearward
Crossover Frequencies:  60, 125, 1500 and 3000 Hz
Nominal Impedance: 4 ohms
Dimensions (W x H x D):  580 x 1220 x 460 mm (22 ¾" x 48" x 18")
Weight (Packed):  45,5 kg (100 lbs)
Finish:  Solid oak diffractions wings. Oak veneer over high-density particle board woofer enclosure

Warranty: 5 years

Sherwood S-9400

 Sherwood Model S-9400 Solid State Stereo/Dynaquad Amplifier
The perfect match for the S-2400 tuner. Model S-9400 represents true superiority in features, flexibility and specifications. Inputs for two phonos, microphones, two auxiliary inputs, tape deck plus 4-channel decoder (or a second tape deck). Power output of 100 watts RMS (8 ohms, both channels driven at 1 kHz) is outstanding. And built-in Dynaquad Four-Channel matrixing circuit offers thrilling 4-channel sound. Distinctive styling matches the S-2400 tuner (the walnut  case is included at no extra charge)

Design Features
160 watts of power (IHF) at 8 ohms, 50 + 50 watts (RMS) at 8 ohms (at 1 kHz); 40 + 40 watts from 20 - 20,000 Hz. Direct coupled output circuitry. 3 stage preamp section with FET for improved overload equalization accuracy. Instant overload protection (power monitoring relay electronically disconnects speakers if any D.C. potential is detected thus eliminating any damage to amplifier or speakers.)
 Control Features
Master on/off volume control which automatically adds bass at low volume settings. Five position program source selector with complementary indicator lights. High and low filters for eliminating high frequency hiss and low frequency rumble. Linear balance control. Speaker selector switch for controlling 2 sets of speakers, individually or simultaneously. Tape monitor switch for tape playback or direct tape monitoring while recording. Front panel tape jacks for headphones and tape-to-tape dubbing. Loudness switch for defeating automatic bass compensation in loudness control. Full mode switch for monitoring each channel separately, stereo, stereo reverse, or mono.

Four Channel Features
Special individual inputs and outputs for a four channel decoder (may also be used as a second tape monitor) - controllable with front panel "four channel" switch. Built-in Dynaquad four channel matrixing circuit - merely add 2 additional speakers for thrilling four channel sound.
Power Output:  Total music power 160 watts (IHF)
RMS Power Output (both channel driven):
2 x 60 watts at 4 Ω, 1 kHz
2 x 50 watts at 8 Ω, 1 kHz
2 x 40 watts at 8 Ω, 20 - 20,000 Hz
Harmonic Distortion:  0,8% (at 8 Ω rated output; 0,10% at 10 watts)
Intermodulation Distortion:  0,6% (at 8 Ω reted output; 0,25% at 10 watts)
Speaker Output Impedance [stereo, mono]:  4, 8 or 16 Ω
Stereo Headphone Output: High or Low output
Stereo Recording Output:  230 mV, 2 k Ω
Power Bandwidth:  5 - 45 kHz -1% Dist.
Frequency Response:
Aux :  20 - 20,000 Hz ±½ dB
Phone :  RIAA standard ±1,0 dB
Damping Factor:  40 : 1 at 8 Ω
Bass Control :  ±12 dB at 100 Hz
Treble Control :  ±12 dB at 10 kHz
Input Sensitivity (for rated output):
Phono :  1,8 mV
Aux :  200 mV
Mic :  2,1 mV
Input Capability (for 1% Dist.):
Phono :  80 mV
Aux :  Infinite
Mic :  60 mV
Hum and Noise (IHF):
Phono :  -60 dB
Aux :  -85 dB
Vol. Control Min. :  -90 dB
Crosstalk:  -45 dB at 1 kHz
Mic. Input Impedance:  50,000 Ω
Power Requirements:  115 - 125 V, 50/60 Hz;  20 -200 watts fused
AC Outlets:  Switched (2 total) 180 watts; unswitched (1 total) 200 watts
Dimensions (W x H x D):  17½" x 5½" x 14"
Weight (shipping):  29 lbs

Cabinet :  walnut case included

Sherwood S-2400

 Sherwood Model S-2400 Solid State AM/FM Stereo Tuner
For those who prefer the versatility of separate components, Sherwood offers the S-2400 AM/FM stereo tuner, which incorporates every advanced circuit design and component device known to be reliable. Performance specifications are unequalled in its price range; the features offer outstanding flexibility and ease of operations; and the styling speaks for itself (the walnut case is included at no extra charge).

Design Features
1,8 µV FM sensitivity (IHF). Four gang variable tuning capacitor. Junction type FET's in primary and secondary RF stages - image rejection is better than 90 dB. Sherwood's new solid state ceramic FM IF filtering circuit provides superior selectivity and stability and lower FM distortion.
 Control Features
Two meters provide tuning for absolute center channel and maximum signal strength, indicator lights for AM, FM and FM Stereo. Linear dial for ease in channel location. Balanced flywheel for velvet action tuning. Separate power off/on switch. "Stereo only" switch permits listening only to stereo stations - monophonic stations are muted. Selector switch for choice of AM, FM, Mono or FM Stereo. Variable output volume control to control or match tuner putput to the amplifier. FM muting to eliminate unpleasant noise while tuning between stations.  Multiplex noise cancellor to reduce high frequency multiplex noise. Rear outputs for oscilliscope.

Four Channel Feature
"Four channel" FM output jack on rear panel permits four channel reception (with use of a special demodulator) when the FCC approves a method of broadcasting four discrete channels.
FM Tuner Section
FM Sensitivity (IHF):  1,8  µV (-30 dB noise and distortion)
Signal-to-Noise Ratio:  -70 dB
Capture Ratio:  1,5 dB
Suppression of AM:  -60 dB
Tuning Range:  87,5 to 108,5 MHz
Distortion:  0,25% at 100% Modulation
Spurious Response Rejection:  -90 dB
Stability:  ±15 kHz (±.015%)
Image Rejection:  -85 dB
IF Rejection:  -90 dB
Alternate - Channel Selectivity:  65 dB
stereoSeparation:  40 dB at 1 kHz
Frequency Response [stereo]:  20 -15 kHz ±1 dB
Antenna:  300 Ω balanced; 75 Ω coaxial
AM Tuner Section
Sensitivity:  10 µV at 30 % mod. For 20 dB S/N
Selectivity:  at ±10 kHz; -30 dB
Frequency Response:  -6 dB at 5 kHz
Tuning Range:  530 to 1625 kHz
Image Rejection: -70 dB at 1 MHz
IF Rejection:  -80 dB at 1 MHz
Antenna:  Ferrite Rod (rotatable) , external antenna input
Power Requirements:  115 - 125 V,  50/60 Hz , 15 watts fused
Dimensions (W x H x D):  17½" x 5½" x 14"

Weight (shipping):  24 lbs

Yamaha CR-840

 When speaking of the OTS (Optimum Tuning System), an easy-to-use Yamaha feature that automatically locks in the exact center of the tuned channel - for the lowest possible distortion.
"the muting and OST systems operated flawlessly" Stereo Review said, and more "The harmonic distortion of the CR-840 was so low that without the most advanced test instruments it would have been impossible to measure it."
 Among Yamaha's most significant features is the continuously variable loudness control. By using this control, the frequency balance and volume are adjusted simultaneously to compensate for the ear's insensitivity to high and low frequency sound at low volume settings. Thus, you can retain a natural-sounding balance regardless of listening level.
 And there' more. Like the Rec Out/Input Select feature. These separate controls allow you to record from one program source while listeningto another program source. All without disturbing the recording process, Stereo Review's comment was, … the tape recording functions of the CR-840 are virtually independent of its receiving functions." one could not ask for greater flexibility.
 In summing up their reaction to the CR-840, Stereo review said, "Suffice it to say that Yamaha make it possible for a moderate-price receiver to provide performance that would have been unimaginable only a short time ago." And the CR-840 is only one example in Yamaha's fine line of receivers.

Audio Section
Minimum RMS Output Power per Channel:
65 Watts at 4 Ω from 20 - 20,000 Hz (at no more that 0,02% THD)
60 Watts at 8 Ω from 20 - 20,000 Hz (at no more than 0,02% THD)
Continuous RMS Power (both channels driven, 1 kHz):
75 Watts at 4 Ω
65 Watts at 8 Ω
Signal-to-Noise ratio (IHF A Network)
Phono :  94 dB (Input shorted)
Aux, Tape 1 and 2 :  100 dB
Residual Noise : 0,17 mV
Distortion 20 Hz to 20 kHz:
Phono to Rec Out :  0,02% 1V output
Aux, Tape to Sp Out ( 8 Ω) :  0,01% at 30 W
Noise-Distortion Clearance Range (NDCR) for 0,1% into 8 Ω at 1 kHz:
From 10 mW to 60 Watts with Vol -20 dB (Phono Input to SP out)
Power Bandwidth (IHF):  10 Hz to 40 kHz
Damping Factor (at 1 kHz):  better than 40 into 8 Ω
Iunput Sensitivity / Impedance:
Phono :  2,5 mV / 47 k Ω
Aux, Tape 1 and 2 :  120 mV / 40 k Ω
Maximum Input levels:
Phono :  140 mV at 1 khz
Output level / Impedance:
Rec Out terminals Phono :  120 mV / 220 Ω (rated)
Aux , tape :  120 mV / 5 k Ω
Frequency Response:
Phono RIAA deviation :  0,4 dB
Aux, tape 1 and 2 to Sp Out :  20 Hz to 20 kHz, ±0,3 dB
Tone Control Characteristics
Bass Turnover Frequency :  350 Hz
Bass Boost/Cut :  ±10 dB at 50 Hz
Presence Center Frequency :  3 kHz
Presence Boost/Cut :  ±6 dB
Treble Turnover Frequency :  3,5 kHz
Treble Boost/Cut :  ±10 dB at 20 kHz
Filters and Loudness Control Characteristics:
Low : 25 Hz (12 dB/octave)
High :  8 kHz (6 dB/octave)
Loudness Control :  Level-related equalization
FM Tuner Section
Tuning Range:  87,6 to 108 MHz
Usable Sensitivity [300 Ω/75 Ω]:  9,3 dBf (1,6 µV) / 9,3 dBf (0,8 µV)
50 dB Quieting Sensitivity :
Mono : 15,3 dBf (3,2 µV)
Stereo :  37,3 dBf (40 µV)
Image Response ratio (98 MHz):  80 dB
IF Response Ratio (98 MHz):  100 dB
Spurious Response Ratio (98 MHz):  100 dB
AM Suppression Ratio (IHF):  60 dB
Captur Ratio:  1,5 dB
Alternate Channel Selectivity:
Locl : 48 dB (IHF)
DX :  82 dB (IHF)
Signal-To-Noise Ratio IHF (at 65 dBf):
Mono :  84 dB
Stereo :  80 dB
Distortion (at 65 dB)
100 Hz :  0,1%
1 kHz :  0,08%
6 kHz :  0,15%
100 Hz :  0,1%
1 kHz :  0,1%
6 kHz :  0,2%
Intermodulation Distortion (IHF) [Mono/Stereo]:  0,08% / 0,08%
Sub-Carrier product Ratio:  609 dB
Stereo Separation
50 Hz :  45 dB
1 kHz :  50 dB
10 kHz :  45 dB
Blend :  10 dB
Frequency Response
50 Hz to 10 kHz ,  ±0,4 dB
30 Hz to 16 kHz , +0,4 -1,0 dB
Muting Threshold:  19,2 dBf (5 µV)
Auto DX Sensitivity:  36,1 dBf (35 µV) or at 50 dB /N
AM Tuener Section
Tuning range:  525 to 1605 kHz
Usable Sensitivity (IHF):  15 µV
Selectivity (1,000 kHz):  30 dB
Signal-to-Noise Ratio:  50 dB (at 80 dB/m)
Image response Ratio (1,000 kHz):  40 dB
IF response Ratio (1,000 kHz):  35 dB
Spurious Response Ratio (1,000 kHz):  60 dB
Total Harmonic Distortion:  0,4%
Tuner Section Output level/Impedance
FM (100% mod. At Rec Out) :  450 mV /3,9 k Ω
AM (30% mod. At Rec Out) :  150 mV / 3,9 k Ω
47 Transistors;  9 ICs; 1 FeT; 14 Diodes, 3 Zener Diodes; 7 LEDs; 5 Ceramic Filters
Power Supplies:  AC 120 V, 220 V  50/60 Hz
Power Consumption:  340 W at 120 V
Dimensions (W x H x D):  510 x 167 x 386 mm (20" x 6-9/16" x 15-1/4")

Weight:  13,6 kg (30 lbs)