.

Combine a Fisher stereo tuner and a Fisher stereo control amplifier on one chassis and the fabulous result is an integrated Fisher stereo receiver, with the over-all performance of a quality formerly obtainable only with separate components. The finest in stereo can now be enjoyed in the simplest of installations.

OUTSTANDING FEATURES OF THE FISHER 500-C AND FISHER 800-C 75-WATT STEREO MULTIPLEX RECEIVERS.

• STEREO BEACON • instantly signals and automatically switches to stereo or mono operation, using a new silicon diode switch for completely silent operation. • Powerful 75-watt audio amplifier will drive the most inefficient speakers to full room volume. • New FISHER GOLDEN SYNCHRODE* front-end for noise-free FM reception, free of image or spurious signal interference. The FM front-end is the most sensitive ever designed for a receiver. • The FISHER DIRECT-TAPE-MONITOR system*. • CONTROLS for the FISHER 500-C: Speaker Selector (speaker 1, speaker 2, speaker 1 + 2, earphones), Bass, Treble, Balance, High Filter, Low Filter. MPX Filter, Tape Monitor, Loudness Contour, Tuning, Volume (AC OFF), Selector (tape head, phono mono, phono, STEREO, FM AUTOMATIC, FM STEREO, FM MONO. AUX-TAPE).
• CONTROLS for the FISHER 800-C: Speaker selector (SPEAKER 1, SPEAKER 2, SPEAKER 1 + 2, EARPHONES), Bass, Treble, Balance, High Filter, Low Filter, AM Bandwidth. (sharp, broad), Tape Monitor, Loudness Contour, Tuning, Selector (tape head, phono mono, phono stereo, fm automatic, fm stereo filter, fm mono, am, AUX-TAPE), Volume and AC OFF.
.

TECHNICAL SPECIFICATIONS OF THE FISHER 500-C AND FISHER 800-C 75-WATT STEREO MULTIPLEX RECEIVERS.

• FM SECTION for the FISHER 500-C and the FISHER 800-C. Usable Sensitivity (IHF Standard) 1.8 microvolts.
• Sensitivity (20 db quieting with 72-ohm antenna) 0.6 microvolts. • Signal-to-Noise ratio (100% Modulation) 70 db.
• Selectivity (alternate channel) 60 db. • IF Rejection (at 100 Mc) 90 db. • Image Rejection (at 100 Mc) 65 db. • FM Harmonic Distortion (400 cps, 100% Modulation) 0.5%.
• FM Stereo Separation (at 1 Kc) 35 db. • Capture Ratio, 2.5 db. i Calibration Accuracy 0.2%. • Drift0.01%. • AM SECTION (FISHER 800-C only) : Sensitivity (for 2 watts output, at 1 Mc) 5 microvolts. • Selectivity (SHARP position, at 1 Mc) 55 db. • Image Rejection (at 1 Mc) 70 db. • IF Rejection (at 1 Mc) 80 db. • AMPLIFIER SECTION: Music Power (IHF Standard 75 watts total. • Harmonic Distortion (at 1 Kc and rated output) 0.5%. • RMS Power (0.7%. Harmonic Distortion at 1 Kc, both channels driven) 60 watts.
• IM Distortion (60 cps + 7 Kc, 4:1) 0.7% at 35 watts, each channel. • Frequency Response: Overall, 25-25,000 cps ± 1.5 db; Power Amplifier Section, 5-45,000 cps + 0, —2 db.
• Hum and Noise (High Level Input) 80 db below rated output.
• Channel Separation (at 1 Kc) 50 db. • Bass Controls (total variation at 50 cps) 23 db. • Treble Controls (total variation at 10 Kc) 23 db. • Low Filter (—3 db at 60 cps) 12 db per octave below 50 cps. • High Filter (—3 db at 5 Kc) 12 db per octave above 6 kc. • Input Sensitivity (for rated output) PHONO: 3.3 mv. TAPE HEAD: 2.5 mv. AUX: 230 mv.
• Power Requirements (105-120 volts, 50 to 60 cycle operation) 210 watts (at 10 watts output); 235 watts (full power). • CHASSIS DIMENSIONS: 17y2" wide, 5%" high, 13y2" deep. • WEIGHT: 500-C: 36y2 pounds; 800-C: 37 pounds.

OUTSTANDING FEATURES OF THE FISHER 400 60-WATT FM-STEREO-MULTIPLEX RECEIVER

. • Exclusive STEREO BEAM* instantly signals stereo multiplex programs. • Front-panel earphone jack permits one to listen to stereo or mono programs in complete privacy, without disturbing others in the same room. • Highly sensitive FM tuner assures clear reception of stations that are beyond the range of other tuners. Three tuned circuits in the front-end provide high degree of selectivity and freedom from IF and image interference.
• Single function Selector switch provides selection of stereo or mono programs and the input source, whether records, radio or tape. • FISHER DIRECT-TAPE-MONITOR* permits monitoring of tapes without sacrificing the use of the complete range of audio controls on subsequent playback. The Tape Monitor switch is used for monitoring and the AUX-TAPE position on the Selector switch is used for playback. • Center channel output. • Provisions for the use of a tape deck.
• SPACEXPANDER® jacks. • Choice of Phono input sensitivity to match any phono cartridge. • Two convenient AC outlets for connection of associated equipment. • Softly illuminated slide rule dial. • Flywheel tuning action. • Architectural brass-finish front panel. • CONTROLS: Speaker earphone selector switch. Bass, Treble, Selector (tape, phono-mono, PHONO-STEREO, FM-STEREO, FM-STEREO FILTER, FM-
mono, aux), Tape Monitor, High Filter, Loudness Contour. Tuning, Volume and AC OFF.

TECHNICAL SPECIFICATIONS OF THE FISHER 400 60-WATT FM-STEREO-MULTIPLEX RECEIVER • FM SECTION:

Usable sensitivity (IHF standard, 300-ohm antenna, 100% modulation) 1.8 microvolts. • Noise figure 3 db. • Signal-to-Noise-and-Hum ratio (100% modulation) better than 70 db.
• Selectivity (Alternate Channel) 60 db. • Image Rejection (at 100 Mc) 57 db.
• IF Rejection (at 100 Mc) 85 db.
• Spurious frequency Rejection better than 90 db.
• Capture Ratio (IHF) 2.5 db. • FM Harmonic Distortion (400 cps, 100% modulation) less than 0.5%.
• FM-Stereo Separation (at 1 Kc) 35 db. • Drift 0.01%.
• Calibration accuracy 0.2%.
• AMPLIFIER SECTION: Music Power (IHF Standard) 60 watts.
• Harmonic Distortion (at 1 Kc and rated output) 0.5%. * RMS Power (0.8% Harmonic Distortion at 1 Kc, both channels driven) 50 watts.
• IM Distortion (60 cps + Kc, 4:1) 0.8% at 52 watts, both channels.
• Frequency Response: Overall, 25-25,000 cps ± 1 db; Power Amplifier Section, 10-40,000 cps 0, —2 db.
• Hum and Noise (High Level Input) 80 db below rated output.
• Channel Separation (at 1 Kc) 50 db.
• Bass Controls (total variation at 50 cps) 22 db. • Treble Controls (total variation at 10 Kc) 22 db.
• High Filter (—3 db at 5 Kc) 12 db per octave above 6 Kc.
• Input Sensitivity (for 25 watts output per channel) PHONO LOW: 4.4 mv. PHONO HIGH: 14 mv. TAPE HEAD: 2.8 mv. AUX: 280 mv. TAPE MONITOR, Switch On: 1.15 v. Selector at AUX-Tape: 440 mv.
• Power Requirements (105-120 volts, 50 to 60 cycle operation) 160 watts (at 10 watts output) ; 200 watts (at full power output). • CHASSIS DIMENSIONS: 17%" x 534" x 13".
• WEIGHT: 3034 pounds. -  Patent Pending

.

Several significant advancements in front-end circuitry, the application of the Time-Division system in the multiplex converter, and a wealth of new convenience features - these are some of the reasons why FISHER stereo multiplex tuners are today, as always, universally recognized as the finest in the world.

.

• Dieser Tuner hat eine motorische Senderwahl samt Fernbedienung, das war im Zeitalter der Röhrentechnik enorm. - Wir haben in 2018 solch einen MF-300 Tuner als Kellerfund geschenkt bekommen. Der Artikel über diese beiden Geräte steht hier. Die ausführliche technische Beschreibung steht weiter unten.
  

.

World-famous Fisher Engineering Laboratories have been responsible for more engineering breakthroughs and more significant innovations in the audio science than any other single group. Regardless of the FISHER FM Tuner you select, you can be assured of enjoying an instrument that is without equal — in its appearance, function, quality of performance, and convenience of use. Here are some of the more recent achievements in FM Stereo Tuner design that are truly hallmarks in the advancement of audio engineering.

This new FISHER front-end design comprises a high-gain, frame-grid triode plus three tuned variable circuits and an additional fixed input circuit of revolutionary design. It affords extremely high selectivity and rejection of spurious image and IF response, with far greater overload protection than any previous design. This feature is particularly important in those urban areas having a number of nearby, powerful radio stations.

This widely-acclaimed FISHER front-end design provides unprecedented sensitivity as well as outstanding image and spurious response rejection. In the FISHER FM-200-B, MF-300 and the FISHER FM-1000, the famous GOLDEN CASCODE circuit uses a four-gang variable condenser (four separate, tuned circuits) to provide a degree of selectivity heretofore considered unattainable.

These FISHER inventions make multiplex a pleasure, not a problem! For the complete enjoyment of stereo programs, FISHER engineers created exclusive STEREO BEAM and STEREO BEACON. STEREO BEAM automatically signals the presence of FM-Stereo Multiplex programs. STEREO BEACON not only automatically indicates (with a jewel-beacon) the presence of FM-Stereo programs, but automatically switches the equipment to stereo operation. On monaural programs, STEREO BEACON automatically switches the equipment to mono operation. Every FISHER tuner and receiver features STEREO BEAM or STEREO BEACON as one of many advanced engineering features.

The fabulous, new Remote Control FM-Stereo-Multiplex Tuner. As an entirely new wide-band FM-Stereo-Multiplex Tuner, the MF-300 is comparable to the finest Fisher tuners in its performance, design and basic front-end circuitry. As an instrument with a remote control unit, or optional wireless remote control transmitter-receiver, it represents a significant breakthrough in audio technology.
.

of both the FISHER MF-300 remote unit, and its optional wireless remote control Model RK-20, transmitter-receiver.

EXCLUSIVE TUNE-O-MATIC MOTOR TUNING
Extensive tests prove that FISHER TUNE-O-MATIC motor tuning is three times more accurate than the most careful manual tuning, even with laboratory-type tuning meters.

EXCLUSIVE WIRELESS REMOTE CONTROL (OPTIONAL) WITH TILT-TUNE
Automatic tuning action and volume level setting can be controlled from any part of the room by pressing the TUNE or VOLUME control button. Tilting the Remote Control Unit to the left moves the dial pointer in that direction, (or lowers the volume). Tilting the Remote Control Unit to the right moves the dial pointer in that direction, (or raises the volume). The entire high fidelity system can be turned off, or on, with the Remote Control Unit (excepting the transistorized Remote Control Receiver which uses negligible current).

EXCLUSIVE MULTI-TUNING FLEXIBILITY AND CONVENIENCE
There are three different methods of tuning. Tuning can be accomplished by (1) using the two pushbuttons on the MF-300 control panel; (2) using pushbuttons on the wire remote control unit, Model RK-10, or the wireless remote control unit, Model RK-20; and (3) using the tuning knob for manual tuning. AFC can be switched off during tuning for maximum manual tuning accuracy. During the automatic tuning sequence, AFC is atomatically defeated until the exact center-of-channel position is reached. Then, the powerful AFC circuit comes into operation, to correct the infinitesimal tuning error, if any, of the TUNE-O-MATIC circuit.

EXCLUSIVE THREE-POSITION MUTING SWITCH
With the Muting Switch in OFF position, the TUNE-O-MATIC circuit will stop at all stations on the band, even those so weak that an ordinary tuner could not receive them. With the switch in NORMAL position, these weak stations are bypassed by the TUNE-O-MATIC circuit. With the Muting switch in MAX position, the TUNE-O-MATIC will stop only at stations delivering a powerful signal at the location. In extreme fringe areas, this eliminates interference or other difficulties occasionally present in such locations. Regardless of the position of the Muting Switch, once the exact center-of-channel is reached, the full sensitivity of the tuner is restored, for optimum performance.

THREE-POSITION SELECTOR SWITCH
The MONO position prevents interference on stations broadcasting subscriber background music. The AUTOMATIC position provides normal reception for both mono and stereo programs. The STEREO position provides locked stereo reception on fading signals.

TRANSMITTER. The two pushbuttons on the transmitter are marked "TUNE" and "VOLUME" respectively. Depress the "TUNE" button and tilt to the left to move the dial pointer in that direction. Tilt to right for tuning to the right. Depress the "VOLUME" button and tilt to left for less volume, and for turning off the entire high fidelity system; tilt to right to turn on the system and for increased volume.

REMOTE CONTROL RECEIVER. There are two basic controls on the receiver — an ON-OFF pushbutton to shut off the operation of the Remote Control Receiver itself, and a Stereo Volume Control with illuminated position indicator. By turning this control fully counter-clockwise, the entire high fidelity system can be shut off.
One can turn on the entire high fidelity system, by remote control, by depressing the VOLUME pushbutton on the transmitter and tilting the unit to the right. This also increases the volume level. The volume control setting is shown by a bright red indicator light and is visible at any distance. Since it is necessary for the remote control receiver to remain in operation under normal use to be able to receive all commands, a green STANDBY light indicating this status remains lit even when the entire high fidelity system is shut off. To shut off all the equipment, simply press the ON-OFF pushbutton at the top of the remote control receiver.

.

An amplifier has two basic functions - to boost signal strength and control signal characteristics. Separate Fisher power and control amplifiers achieve the ultimate degree of perfection. They are the finest professional amplification systems in existence. When both functions are integrated in one chassis, the result is a Fisher Master Control Amplifier in a class of perfectionist equipment formerly available only as a two-chassis system.

The newest series of Fisher Amplifiers was designed explicitly to meet the needs of people who demand technical versatility as well as 'no-compromise' design. Preserving intact the functional specialties of individual units, Fisher has produced an outstanding group of Amplifiers incorporating the most advanced engineering developments.
.

A New Convenience Feature
The new FISHER X-101-C master control amplifier was designed to be the first genuine all-family amplifier in high fidelity history. For the audiophile members of the family, the FISHER X-101-C incorporates comprehensive controls of utmost versatility. But for immediate enjoyment of stereo by even the least technically inclined members of the family, only the 'must' controls are in full view, for instant use. These frequently-used controls consist of the Pushbutton Program Selector (tape head, phono, tuner, aux, tape play), Mode Selector (stereo, mono, reverse), and Volume Control. The occasionally-used controls are hidden behind the Control Cover, yet are immediately accessible when needed. They consist of four controls (output selector, bass, treble, balance), and four switches, (equalization, high filter, tape monitor, loudness contour.)
.

.

THE FISHER SA-1000 150-Watt (IHF) Power Amplifier has more than enough power to drive any speakers in any room under any listening condition. This professional-type power amplifier, years ahead of its time in basic design, circuitry and overall engineering concept, is representative of the achievements of Fisher Engineering Laboratories. This instrument possesses ample reserve capacity for all applications, including use in the largest auditoriums and theatres, although conservatively rated at 130 watts of RMS Power, and 150 watts of Music Power with both channels operating simultaneously.

The Output Stage of the FISHER SA-1000 features the newly developed Type 8417 beam power pentode, never before used in any electronic device. This new tube, specifically designed for application in the SA-1000, offers extreme linearity resulting in very low distortion. Each pair of 8417 tubes, operating in Class AB with fixed bias, drives an over-sized output transformer via plate-cathode coupling (modified ultra-linear). The cathode coupling provides 12 db of negative feedback in the output stage to reduce distortion without affecting stability due to the phase shift problems usually associated with high overall feedback. High frequency distortion is thus significantly reduced in the output stage since the feedback provided by the cathode coupling is fully effective throughout the frequency range.

The output transformer itself is custom-wound to rigid Fisher specifications. Besides its conservative design, its one remarkable characteristic is the extremely smooth roll-off below 5 cps and above 200 kc without peaks or dips. This results in an exceptional stability and square wave performance.

The Driver Stage in a high-power, high quality power amplifier, is often considered as important as the output stage, because of its effect on the "sound" or listening quality of the instrument. It is not only important that the driver provide sufficient, low distortion signal, but that it do so at a very low impedance to promote stability and transient response in the output stage. To do this effectively, the Fisher Engineering Laboratories have developed a novel driver stage utilizing a 6HU8/ELL80 dual power pentode in a triode-connected configuration. This circuit is capable of delivering 40% more drive than the required signal — and at an extremely low impedance. More important, it has an unusually rapid recovery time resulting in superb transient response.

The Pre-Driver, Phase-Inverter utilizes an ECC83/12AX7 dual tri-ode in DC coupled Cathodyne phase-splitter. This Cathodyne (or cathode-follower) type phase inverter was selected for its self-compensating ability to maintain balance despite tube aging. A feedback loop from the output transformer secondary to the pre-drive cathode provides 17 db of feedback to maintain low distortion in the pre-driver, phase-inverter and driver stages.

The Input Stage of the SA-1000 is unique in that its compensated attenuator, cathode-follower configuration is generally used only in laboratory oscilloscopes.
The cathode follower circuit was chosen for several reasons: it assures a high input impedance to prevent loading of the input source; provides complete isolation between the input and the feedback circuit (the pre-driver cathode) ; maintains a wide frequency response. In reference to this last characteristic, it is interesting to note that the pre-driver stage itself is flat to within ± 1.0 db up to 11 megacycles!

A switchable sub-sonic filter is provided in the grid circuit to prevent speaker damage as a result of turntable rumble, off-center records, etc. The input attenuator provides calibrated 3 db steps from 0 to —12 db while maintaining a constant input impedance. This permits operating the preamplifier volume control at its optimum range.

The tube in this stage, also of recent design, is specifically intended for input stages because of its unusually low hum and noise, and also features a built-in shield completely isolating both sections.

The Power Supply in The FISHER SA-1000 is unusually elaborate for a power amplifier. To provide full power output with both channels driven, separate rectifier-filter circuits are used for the plate and screen-grid supplies of the output tubes. An additional rectifier-filter supplies bias voltage. Silicon diodes are used throughout to improve regulation and promote trouble-free service.

Extensive filtering (a total of 780 mfd) helps assure an extremely low hum of better than 90 db below rated output. In keeping with the conservative design, the diodes and capacitors are worked well under their ratings. In fact, the diodes are capable of supplying 2 to 3 times the current required for full output.

The perfection of sound reproduction: high compliance and high efficiency in new compact enclosures of unequalled excellence.

THREE-WAY SPEAKER SYSTEM —
The new FISHER XP-1A has the most advanced engineering features, including a balance control to permit the user to adjust the ratio of the low and high- frequency response to suit precisely the demands of the room acoustics and personal taste.

THREE-WAY SPEAKER SYSTEM —
In the FISHER XP-2A Speaker System, the many advantages of FISHER high-efficiency, high-compliance design have been incorporated in a unit of moderate price. Through its carefully evolved design, the FISHER XP-2A offers a remarkable transient response and an unusually high overload capacity.

SLIM-LINE THREE-WAY SPEAKER SYSTEM —
Extreme clarity, precise transients, full and rich texture — these are of a calibre truly unprecedented in a system of this compact size. The new FISHER KS-1A lends itself to virtually any type of installation. It can be mounted on a wall or placed on the floor, without degradation in bass response.

Wide-Surround® Speaker System
These extremely compact units augment the sound from the primary speaker systems to create a breadth of music reproduction that makes every seat in the room a 'front-row-center' location. The FISHER Wide-Surround® system will overcome the 'point source' of sound, and give the listener the illusion that he is sitting in one of the most desirable seats in the concert hall.
OUTSTANDING FEATURES • 10" x 2%" oval, Alnico V permanent magnet speaker. • Frequency Response: 250 to 15,000 cps, cutoff at 250 cycles. "Available in modern, Walnut or Mahogany; French provincial, Cherry; Italian provincial, Distressed Walnut. • dimensions: 11%" wide, 3%" high, 4%" deep. weight: 4>y2 pounds.

Anmerkung: Das sind Überbleibsel, die bestimmt unbedingt noch abverkauft werden mußten.

For Concealed Installation
Your present stereo system is not obsolete! Add a FISHER Multiplex Adaptor to any good quality tuner and you can enjoy FM-Stereo-Multiplex.
OUTSTANDING FEATURES OF THE FISHER MPX-100
• Selector (ac power, tuner, stereo-mono automatic, stereo manual). • Two-Position Noise Filter • Auxiliary AC receptacle on rear apron. • Dual Output Level Controls.
• Variable Separation Control. • Two Output and Four Input Jacks. • Cabinets in Walnut, Model 40-UW, and Mahogany, Model 40-UM. • chassis dimensions: 4%" wide, 4 13/16" high, 12" deep. • weight: 9 pounds.
OUTSTANDING FEATURES OF THE FISHER MPX-200
• Self-powered. • Can be placed up to three feet from tuner or receiver. • Two Level Controls match the volume of the Stereo programs to phono, tape, etc. • Selector Switch to record stereo programs monophonically! • Precision separation control matches the MPX-200 to any tuner or receiver. • Unusually effective filtering, for flawless tape recording. • chassis dimensions: 12" wide, 4" high, 3%" deep. • WEIGHT: 3% pounds. *Patent Pending

The StrataKit method of construction permits assembly by easy, error-proof stages (Strata), each stage corresponding to a specific, illustrated page in the Instruction Manual and to a separate, clearly identified transparent packet of parts. Large, three-dimensional diagrams guide you every step of the way. Just perform the numbered step and check it off. Errors of omission, if any, can thus be checked stage-by-stage and page-by-page before proceeding to the next stage. It's that simple with a FISHER StkataKit. Major components come already mounted on the chassis, and wires are pre-cut to length and pre-stripped for every stage. Schematic diagrams are also included for those who like to see how the various electronic circuits are designed.

.

Now music lovers everywhere can enjoy a complete selection of their favorite records — even intermix 7", 10" and 12" records — without any disturbance or interruption to their musical pleasure. The amazing new Fisher-Lincoln will not only take up to ten records at one time, but will play all twenty sides without anyone lifting a finger.

Unlike mass-produced mechanical record changers, the Fisher- "Lincoln Model 70" utilizes air as the motive power for all movements, thus providing a resilient cushion which prevents jamming of mechanical parts. This laboratory-quality record player is so trouble-proof, so easy to operate, and so smooth and quiet, that comparison to any existing brand is impossible.

OUTSTANDING FEATURES
• Automatically plays BOTH sides of each record, or one side only. Handles 33% RPM speeds of 7", 10" and 12" records intermixed, and in any sequence.
• Handles up to ten records (twenty sides) — over eight hours of continuous music. Also plays single records (one or both sides.)
• Conical-shaped Teflon bearings in the turntable, which run
on polished hardened steel, completely eliminate the need for any lubrication during the life of the record player.
• Records are transported even more gently than one could by hand. No metal touches the record at any time during play. There is no stationary spindle and therefore center-hole wear is eliminated.
• The only record in motion during operation is the one actually being played. There is no slippage. Furthermore, the tone arm and stylus are always at the ideal angle. (On all other changers the stylus angle can be correct only for one of the records in the stack being played.)
• Studio quality, belt-driven turntable, precision heavy-duty motor. Drive wheels are released automatically at the end of play, eliminating rumble usually caused by drive wheel distortion.
• Final record grooves are protected against wear by the use of a proximity switch which is completely independent from the operational mechanism of the record player.
• Tone arm is designed with standard mount, for all makes of cartridges. Landing position is easily adjustable.
Specifications: 110 volts; 60 cycles ; maximum power consumption 4 amps. Shipping Weight: 65 lbs. Overall Space Requirements: 27" front to back, 19" high, 15^4" wide.
.

.

• AF (AUDIO FREQUENCY) Frequency within the range of human hearing - approximately 20 to 20,000 cps. Applies both to soundwaves and to the electrical signals which represent them.
• AM (AMPLITUDE MODULATION) Modulation accomplished by varying the instantaneous amplitude (intensity) of the carrier. Since an AM receiver must therefore be able to detect amplitude variations, it responds equally well to naturally-produced amplitude peaks: lightning, ignition interference, etc.
• AUDIO Used interchangeably with AF. Also, the science of sound recording and reproduction, including acoustics.
• CAPACITOR (CONDENSER) Circuit device capable of storing electric charge. It also has the property of passing alternating current while blocking direct current, and of presenting a greater resistance to the flow of alternating current as its frequency decreases. All these properties are used in electronic circuits.
• CAPTURE RATIO Ability of a tuner to reject unwanted FM stations on the same frequency as a desired one; measured in db. The lower the figure, the better the tuner's performance.
• CARRIER A steady RF alternating current radiated into space by a transmitter-and-antenna system.
• CASCODE Circuit designed around two low-noise triode tubes which provides approximately the same amplification as a pentode, but with less noise. This makes it ideal for amplification of weak FM signals.
• CROSSOVER NETWORK Circuit for dividing the audio range into two or more parts before feeding the signals to separate 'specialized' speakers: woofers, mid-range, and tweeter.
• DB (DECIBEL) Unit of measure to indicate relative levels of voltage, current, power, or sound.
• DERIVED CENTER CHANNEL Monophonic composite signal derived from the sum or difference of the left and right stereo channels, often fed to an extra speaker to fill in an aural 'hole' between the left and right speakers. A sum (left-plus-right) signal can also be used for feeding a remote speaker elsewhere in the home.
• EQUALIZATION Correction for non-uniform recording of low and high frequencies. For valid technical reasons, disc records are cut with low frequencies attenuated and high frequencies boosted. Equalization compensates electrically for this imbalance and produces a uniform frequency response.
• FEEDBACK Taking a portion of the output signal from an amplifier and feeding it back to the input. Negative feedback tends to make an amplifier self-compensating; irregularities in the output (distortion) not present at the input are cancelled. This applies also to hum, noise, or a non-uniform frequency response.
• FM (FREQUENCY MODULATION) Modulation of a carrier by changing its instantaneous frequency, rather than its amplitude, in accordance with speech or music signals. By designing the FM receiver to respond only to FM, and to reject AM caused by lightning or auto ignition pulses, noise-free reception becomes a possibility. This is one of the advantages of FM which has helped make it popular for high fidelity.
• FREQUENCY Number of "back-and-forth" vibrations of a sound wave or alternating current in a second; expressed as cycles per second (cps.)
• FREQUENCY RESPONSE Range of audio frequencies handled by a system or High Fidelity component.
• GAIN Amount of amplification (in amplifiers or amplifying stages.)
• GOLDEN SYNCHRODE An exclusive FISHER-engineered FM front-end providing high gain at low noise, and superior image and IF rejection. It uses a single high-transconductance frame-grid triode, neutralized for stability and low noise.
• HARMONIC DISTORTION Production of undesired harmonics (overtones) which were not present in the original program material (expressed as a percentage.)
• HUM The low-pitched, steady tone produced in an amplifier by the AC power frequency (60 cps) and its harmonics.
• The only way to protect your investment in high fidelity is to know what you are buying. That is why we always publish full specifications. These specifications are your yardstick, revealing just what you are getting when you buy a FISHER component. Here is a simple explanation of the most important terms.
• IF (INTERMEDIATE FREQUENCY) Constant difference frequency produced by mixing an incoming signal with a signal generated in the set at a different frequency. This superheterodyne principle offers important advantages over other methods of reception.
• IM (INTERMODULATION) DISTORTION Production of undesired tones resulting from mixing, in an amplifier, of two or more pure tones (expressed as a percentage.) Low IM is vital for 'clean' sound.
• IMPEDANCE Resistance to flow of alternating current (expressed in ohms.) Generally changes with the frequency of the applied alternating current.
• LIMITERS FM tuner stages that reject spurious amplitude interference (from atmospheric noise or ignition pulses) and leave a pure, constant-amplitude FM signal. The FM signal fed to such stages must have a certain minimum strength for limiting to occur. As with IF stages, the more stages the better, other factors remaining equal.
• LOUDNESS CONTOUR Compensation for the ear's natural insensitivity to low and high frequencies at low volume levels, achieved by boosting extreme lows and high progressively as volume setting is lowered.
• MODULATION Process of superimposing voice, music or other intelligence on a carrier wave. (See AM, FM, Carrier.)
• MULTIPLEX Transmission of two or more channels on a single carrier so that they can be recovered independently at the receiver; in FM stereo, transmission of left-plus-right (sum) signal and left-minus-right (difference) signal on main carrier and subcarrier, respectively. The multiplex decoder in the receiver recovers independent left and right stereo channels from the multiplexed signal.
• MUSIC POWER- This is the power output of an amplifier according to a rating standard applied by the Institute of High Fidelity (IHF) .
• NOISE Unwanted random sound created in small amounts by electronic equipment, often heard as hiss. Good design reduces it to negligible proportions.
• OSCILLATOR Electronic generator of alternating current. One of the fundamental electronic devices.
• PEAK Maximum instantaneous voltage or power. Also, a sudden, momentary burst of sound.
• POWER OUTPUT Maximum amount of power an amplifier can deliver.
• RESISTOR Circuit device that offers resistance to flow of alternating or direct current. When current flows through a resistor, a voltage proportional both to the current and the resistance exists across it. This property and the fact that a resistor absorbs electric power, dissipating it as. heat, are used in electronics. Resistors are made of wire, metallic film, carbon, and other materials. They can be fixed or variable.
• REVERBERATION Repetitive reflection of sound (from walls, etc.) Also, the spatial effect created thereby, which adds brilliance and warmth to sound, and helps to convey the size of the studio or hall.
• RF (RADIO FREQUENCY) Alternating current of frequency greater than 15 or 20 kc. Specifically, alternating currents transmitted and received for communications or entertainment.
• SELECTIVITY Normally, the ability to reject stations on the same frequency and on channels adjacent or alternate to the one being received.
• SENSITIVITY In a tuner, the ability to provide usable reception of weak signals. Expressed, for FM tuners, as microvolts (millionths of a volt) needed for a given number of db quieting (noise suppression.) The lower the number in microvolts, the more sensitive the tuner.
• SEPARATION In stereo, degree to which channels are kept apart. Stereo effect depends on preventing leakage of program material from one channel to the other.
• SIGNAL-TO-NOISE RATIO Figure in db, expressing the ratio of desired signal voltage to random noise voltage. Look for a high db figure: the better the signal-to-noise ratio, the less background noise there will be in the reproduced program material.
• TRANSFORMER Electrical device which steps up or steps down voltage. A power transformer is used to 'transform' 117-volt AC power ('house current') into various voltages needed to operate a tuner or amplifier.
• Formerly Institute of High Fidelity Manufacturers (IHFM)

.