Fisher 500-TX receiver

AM/FM Stereo Receiver, with Four methods of Tuning

Engineering leadership of thirty two years in creating the finest receiving equipment has reached its culmination in the Fisher 500-TX. This powerful AM-FM Stereo Receiver is truly the connoisseur's dream, incorporating every state-of-the-art. Feature,

 

Four method of Tuning

Manual - Fisher's ultra-smooth flywheel mechanism assures effortless AM and FM tuning across the large, illuminated, easy-to-read dial scale

Pushbutton - Fisher's Tune-O-Matic Memory Tuning provides instant selection of any one of your four favourite FM stations, simply by pushing a button. This is accomplished by four separate tuning mechanisms and four individual dials with separate control knobs on the front panel. Perfectly matched varactor diodes (variable capacitance or "tuning" diodes) select the exact frequency to which each memory is pre-set, assuring precise tuning each time the station is selected. Drift or deviation from the pre-set position is avoided, since the signal frequency is "locked-in" by AFC.

AUTOSCAN Touch Tuning - is the remarkable FM tuning mode which affords effortless scanning of the FM band in both directions, at the touch of a button. Completely electronic with no motors or moving parts, this unique circuit uses the same varactors previously described to tune either one station at a time, or station after station in continuous sequence. Autoscan tunes in complete silence and will lock onto each station with unerring accuracy, to  degree unmatched by any conventional tuning method.

Remote Control - Station selection using the Autoscan circuit may also be accomplished by means of an accessory unit (Fisher RK-30) which provides convenient tuning from a remote position in the listening area. The RK-30 is a hand-held remote control with 20 feet of flexible cable which permits the user to select stations without leaving his seat.

 

Highest Sensitivity

The sensitivity of the 500-TX, is rated at 1,7 µV, representing the all-important factor in the outstanding ability of the tuner to provide strong and clear reception of even the weakest signals. The FM front end consists of a 4-gang circuit incorporating four newly developed varactor diodes plus dual-gate MOSFETs in the RF and mixer stages. A highly efficient AGC circuit effectively prevents overload and distortion in very strong signal areas, such as cities, even though signals as high as one volt are received.

 

Highest Selectivity

Clean reception of weak, distant stations located adjacent in frequency to very strong local stations is provided by a crystal filter in the FM-IF stage of the tuner. Previously available only in the most expensive communications and military receivers, this filter is utilized to its fullest advantage in the 500-TH to pull in distant stations with "crystal" clearness. A distinct advantage of crystal filters, as compared with conventional filter coils, is that they never need alignment.

The AM-IF section is equipped with a 4-resonator ladder-type ceramic filter of exceptionally high selectivity. This filter assures vastly improved reception of distant AM stations and, in addition, eliminates annoying whistles. It provides optimum bandwidth for vastly superior AM reception

The AM section also features a 3-gang variable capacitor, a tuned RF and a mixer section using a newly developed dual-transistor circuit to minimize noise and prevent overloading.

 

Specifications

FM Tuner Section

Usable Sensitivity (IHF Standard):  1,7 µV

Harmonic Distortion (at 400 Hz, 100% Mod.):  less than 0,4%

Signal-to-Noise Ratio (at 100% Mod. 1 mV input):  65 dB

Selectivity Alternate Channel:  70 dB

Spurious Response rejection (at 100 MHz):  100 dB

Image Frequency Rejection (at 100 MHz):  65 dB

IF Frequency Rejection (at 100 MHz):  80 dB

FM Stereo Separation (at 400 Hz):  38 dB

Capture ratio (IHF at 1 mV):  1,5 dB

AM Tuner Section

Sensitivity:  10 µV

Selectivity (at 1 MHz and ±10 kHz):  80 dB

Image Frequency Rejection (at 1 MHz):  70 dB

IF Frequency Rejection (at 1 MHz):  65 dB

Amplifier Section

Music Power (at 1 kHz, 8 Ω ):  200 watts ±1 dB

IHF Dynamic Power (8 Ω ):  75/75 watts

RMS Power (at 1 kHz, 8 Ω ):  65 /65 watts

Total Harmonic Distortion (at 1 kHz):  0,5%

Intermodulation DIstortion (60/7000 Hz, 4;1, smpte):  0,8%

Power bandwidth (IHF, 8 Ω ):  8 to 35,000 Hz

Sensitivity (rated output at 8 Ω )

Phono Low :  2,5 mV

Phono High :  10,0 mV

Auxiliary :  250 mV

Monitor :  300 mV

Recorder Output (30% FM Mod.):  400 mV

Hum and Noise (below rated output)

Volume at Minimum :  -90 dB

Phono Low (6-mV ref.):  -60 dB

Auxiliary (400-mV ref.):  -65 dB

Frequency Response

Phono Low :  30 to 15,000 Hz ±2 dB

Auxiliary :  20 to 25,000 Hz ±1,5 dB

Power Amplifier Section :  15 to 40,000 Hz ±1,5 dB

Maximum Input Signal (at 1% T.H.D.)

Phono Low :  50 mV

Auxiliary :  4,5 volts

Input Impedance

Phono Low :  50 k Ω

Auxiliary :  175 k Ω

Damping Factor (1 kHz, 8 Ω ):  better than 30

Control Tracking Error (0 to -50 dB):  less than 2 dB

Separation (at 1 kHz)

Phono :  better than 45 dB

Auxiliary :  better than 50 dB

Controls

Bass :  24 dB at 50 Hz

Treble :  24 dB at 10 kHz

Subsonic Filter:  12 dB /pcatve below 10 Hz

Low-Frequency Filter (12 dB/octave):  -3 dB at 50 Hz

High-Frequency Filter (12 dB/octave):  -3 dB at 5,000 Hz

General

Power Supply:  100-120 AC, 50/60 Hz

Power Consumption:  Max. 240 watts / 320 VA

Dimensions (W x H x D):  16-7/8" x 4-13/16" x 14-1/2"

Weight:  30 lbs