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
