AH673144 TUNER

PHILIPS HIGH FIDELITY LABORATORIES, LTD.

SIGNAL TUNIN0

AM -
LEVEL-F* LEVEL SELECT
INTRODUCTION
You are now the proud owner of one of the finest tuners on the market; the
Philips Model 673. This high quality instrument incorporates state of the art
design technology and components to give you many years of outstanding
performance and trouble free operation.
The front panel layout is simple and straight forward using a combination of
precision .rotary controls and touch switches with LED (Lighting Emitting
Diode) indicators. f he touch switches provide smooth silent operation without
the "pops" and "clicks" of mechanical Switches. The LED indicator located
above each set of touch contacts tells you at a glance which switches have
been activated.fwo separate adjustments for AM and FM output level provide
you with the ultimate in flexibility and performance. THese variable linear
controls allow adjustment from 0 - 1 volt for each output.
The wide view dial scale features finely etched, precision graphics. The fine
resolution, large viewing length and balanced graduations along with a high
momentum flywheel provide for easy viewing and a smooth, positive tuning
characteristic.
Two tuning meters have been provided as additional tuning aids. The use of
independent center-tune and signal strength meters enables you to tune in a
station quickly and accurately. At a touch of the finger, the center-tune meter
becomes a multipath meter. The multipath meter in conjunction with the
signal strength meter allows you to independently observe optimum signal
strength and minimum multipath. This will permit adjustment of antenna
orientation for optimum signal reception. In addition to this convenient two
meter approach, horizontal and vertical outputs are available on the rear
panel for oscilloscope viewing of multipath.
Full fidelity AM has been incorporated into this tuner for performance and
response on the AM Band approaching that once thought possible.only
through FM transmission. It has often been assumed that the fidelity of AM
would be poor at best, but infact, AM in capable of very good fidelity, wide
range response and low distortion. Also incorporated is a 10 KHz sharp notch
filter which, when activated, considerably reduces any adjacent channel 10
KHz heterodyne whistle when listenin to AM broadcasts. Touch the Automatic
8
Stereo Noise Cancelling Switch, A NC, and it activates a unique circuit
which virtually eliminates the annoyance of noisy FM stereo broadcasts and
provides clear reception of marginally weak FM stereo stations.

The Model and Serial Number of your Philips High Fidelity Laboratories
tuner will be found on the rear or bottom of the instrument. Please record this
Model and Serial Number in the space provided below.
Model Number . Serial N u ~ b e r
~r9dL73~0~~Cf j g 7 7 3q7-3

WARNING - TO PREVENT DAMAGE WHICH MAY RESULT IN FIRE OR

SHOCK HAZARD, DO NOT EXPOSE THIS APPLIANCE TO RAIN OR
EXCESSIVE MOISTURE.
INSTALLATION
LOCATION
The tuner should be placed as close to your other components as is convenient.
Do not locate the tuner in direct sunlight, near radiators or other sources of
heat. Locations having high humidity or excessive dust should be avoided if
at all possible. If you plan to install the tuner in any type of cabinet or
enclosure, be sure to allow for adequateventilation.To insure best performance,
take the time to prepare a location that is sturdy enough to support the tuner
and its associated components.
ADDITIONAL EQUIPMENT
Any additional audio equipment that you may wish to purchase shol-tld be of
the same high quality as this tuner. The Philips 673 is compatible with other
products from Philips High Fidelity Laboratories as well as most other high
quality component equipment.

TUNER CONNECTION
AMPLIFIER
Two pairs of audio output terminals, variable and fixed, are provided on the
rear of the tuner. Connect the variable output terminals to the Tuner or Aux
inputs of the amplifier using the audio cable which is supplied. 'The signal
level from thevariable terminals is controlled by thetwo level controls on the
front of the tuner. The Fixed output terminals may be connected to the Line
Input terminals of a tape deck. Since the signal level from the Fixed output
terminals cannot be adjusted at the tuner, this must be done with the record
level controls of the tape deck.
MULTIPATH
The M~tltipathterminals may be connected to the horizontal and vertical
inputs of an oscilloscope for the purpose of.visually monitoring multipath
distortion. 'This can aid you in positioning the FM antenna for minimum
multipath and maximum signal strength. When operating the oscilloscope,
follow the instruction manual supplied with it.
FM DETECTOR OUTPUT
An FM detector output is available on the back panel, ready for use when 4
channel FM is perfected.
FM ANTENNA
A folded dopole FM antenna has been provided with this tuner. To connect
this antenna, loosen the two 300 ohm antenna screws, slip the "u" shaped
lugs of the antenna under the screws and tighten them securely. The crossbar
of the antenna shol-~ldbe mounted flat and horizontally on the wall, along the
back edge of a shelf or other convenient location.This antenna is directional;
therefore, discovering the best location may require some experimentation.
Although this antenna should be adequate for reception of local stations, you
may wish to install an outdoor FM antenna.
Terminals have been provided for the connection of 75 ohm cable. This type
of antenna cable may be connected by stripping the insulation from one end
and installing the cable as shown in the illustration. It may also be connected
to the tuner by first installing an F type screw on connector on the end of the
cable and then attach the cable to the 75 ohm connector of the tuner as
shown in the connection diagram. Id
300 OHM
FM ANTENNA
TWIN LEAD

75 OHM
COAXIAL
CABLE

When you install an outdoor antenna, it should be oriented to provide maximum

signal strength and minimum reflections. The antenna should be as far away
from roads and streets as possible since passing cars and trucks can cause
reflections. By using the signal strength and multipath meters, the correct
antenna position is indicated by maximum deflection of the signal strength
meter and minimum deflection of the multipath meter.
AM ANTENNA
The bar antenna mounted on the back of the tuner will provide satisfactory

-
reception of local stations. The 3dimensional mounting allows you to position
the antenna to eliminate interference and increase the signal strength.
,:>

AM BAR ANTENNA
I I

If you live in an area where satisfactory reception cannot be obtained by

using the bar antenna, an outdoor AM antenna should be connected to the
AM terminal of the tun r. NOTE: All wires and cables should be
1
routed away from the M antenna since it is possible for these
wires to introduce feedback into the tuner through the antenna.
CONTROLS

MASTER POWER
-
The Master Power switch, located on the back panel of the tuner, controls the
power for all of the circuits except the unswitched AC receptable.'This switch
must be in the On position for the tuner to operate. If the tuner will not be
used for an extended period of time, such as when you are on vacation, place
the Master Power switch in the Off position.
POWER
After placing the Master Power switch in the On position, the Power touch
switch on the front panel is used to turn the tuner On and Off. The LED
indicator above the touch contacts will be lit when the power is on.
FM MULTIPATH
Activating the Multipath switch converts the tuning meter from a center-
tuning meter to a multipath meter for monitoring multipath distortion. This
enables you to adjust the antenna for minimum multipath.
AMIFM LEVEL
The separate Level controls allow you to independently adjust the audio
output for AM and FM. These continuously variable, linear controls provide
adjustments of 0 to 1 volt for each output and enable you to balance the
volume level of the tuner with your other components.
ASNC
The Automatic Stereo Noise Cancelling (ASNC) circuit can be activated
when listening to a noisy FM stereo broadcast.This unique circuit senses the
amount of noise in the broadcast; if the noise rises above a given threshold, a
Schmitt trigger and a switching transistor activate the noise cancelling circuit
to provide clear reception of marginally weak stereo stations. NOTE: When
the ASNC circuit is in operation, it reduces noise on weak stereo stations
without reducing separation on strong stereo stations.
MUTE
The Mute switch is used in conjunction with the Mute Level control to
eliminate interstation noise as well as weak stations. The threshold at which
muting takes place is adjusted with the Mute Level control which is located to
the right of the Mute switch. Minimum muting action occurs with the Level
control placed fully counterclockwise and maximum muting occurs at the
fully clockwise position.
SELECT SWITCH
The Select switch is used to select the different operational modes as follows:
NORMAL- for reception of AM broadcasts.
FIDELITY- for reception of AM broadcasts in Full Fidelity. Most
people assume that AM fidelity will be poor at best and,
therefore, not worthy of their attention. The medium
of AM is, in fact, capable of very good fidelity; much bet-
ter than is usually thought. Philips' Full Fidelity AM cir-
cuits provide a frequency response approaching that
of FM; typically 20 Hz - 10 KHz + 2db with distortion
factor of .5%@ 30% modulation and 1.5%@ 90% modu-
lation.
STEREO ONLY- Perrr~itsreception of only those FM stations which are
broadcasting in stereo. In addition, interstation noise is
automatically muted.
AUTO- Allows reception of stereophonic FM and monophonic
FM broadcasts. A stereo broadcast is indicated by the
illl~minationof the stereo indicator light located to the
left of the dial scale.
MONO- In this position all FM broadcasts are reproduced
rnonophonically.
AM 10 KHz
When the 10 KHz switch is activated, a sharp notch bridgeT - LC filter is intro-
duced into the IF circuit to eliminate adjacent channel 10 KHz heterodyne
whistle.
TUNING
The Tuning knob is used to tune in the desired AM and FM station.
SIGNAL STRENGTH METER
The Signal Strength meter indicatesthe relative strength of the station being
received. This meter will also assist you in properly orienting the antenna for
maximum signal strength.
CENTER/MULTIPATH METER
This meter is used for precisely tuning to the center frequency of an AM or
FM radio station. Turn the turning knob until the needle is at the center of the
scale.
This meter also functions as a multipath meter on FM by activating the
Multipath switch. Using the Multipath meter, adjust the antenna for minimum
deflection of the needle.

OPERATION
Before operating the tuner, check to make sure that all connections have
been properly made and that power is supplied to all of the equipment.

FM RECEPTION
1. Place the Master Power switch in the On position. Turn the tuner on by
activating the Power switch on the front panel.
2. Place the Select switch in the Auto position
3. Turn the Mute off. After you become accustomed to operating the
tuner you may wish toeliminate the interstation noise To do thislacti-
vate the Mute switch and turn the Mute level clockwise until the inter-
station noise is eliminated. As the Level control is turned farther clock-
wise, weak stations will also be muted.
4. Rotate the Tuning knob to locate the desired station. Once the station
is found, observe the signal meter and adjust the tuning knob for maxi-
mum deflection of the needle of the meter. Complete the tuning by ob-
serving the Center-tune meter and adjust the Tuning knob until the
needle is centered.
5. Adjust the FM Level control for a useful level.
AM RECEPTION
1. Turn on Tuner.
2. Place the~selectswitch in the Normal or Fidelity position.
3. Select the desired station in the same manner as you would select an
FM station.
4. Adjust the AM Level control for a useful level.
TYPICAL
SYSTEM
CONNECTIONS

INDOOR FM ANTENNA

LONG WIRE
AM ANTENNA

TUNER INPUT

PREAMPLIFIER
MAINTENANCE
If the tuner fails to operate, checkto besure that the Master Power switch is in
the On position and that the tuner is connected to an active outlet supplying
120 volts, 60 Hz AC. If, after making these checks, the tuner still does not
operate; disconnect the line cord from the electrical outlet and check the
fuse located on the back panel. If the fuse is blown, replace only with a .5amp,
125 volt slo-blo fuse. Plug the tuner in and turn it on. Caution: If the tuner falls
to operateor the fuse blows again after a short time, do not attempt to replace
the fuse again. Disconnectthe line cord and contact your dealer or aqualified
serviceman. Any attempt to replace the fuse with one of a different value may
constitute a fire hazard.
CONTROL PANEL
To clean the control panel, disconnect the AC line cord from the electrical
outlet and use a clean lint-free cloth moistenedwith warm water only. Remove
any excess water before plugging the tuner in.
LAMPS AND INDICATORS
Should any of the control panel lamps or function indicators burn out, do not
attempt to replacethem yourself. Refer servicingto aqualified serviceman.
TECHNICAL SPECIFICATIONS
(Data subject to modification without notice)
FM Section
Tuning Range 87.5 - 108 MHz
Antenna Input 300 ohm Balanced
75 ohm Unbalanced
Usable Sensitivity
Mono 1.6 uv
Stereo 3.0 uv
50 db Quieting Sensitivity
Mono 2.5 uv
Stereo 32 uv
Total Harmonic Distortion
Mono .12%
Stereo .I8%
Capture Ratio 1.2 db
AM Rejection 50 db
IF Rejection 110db
Image Rejection 110db
Spurious Response 110db
Selectivity
(Single Generator) >110db
(Dual Generator) 83 db
Pilot Carrier Suppression 65 db
Frequency Response (+.5 -1.5 db) 20-15 KHz
Stereo Separation
100 KHz 45 db
1 KHz 45 db
10 KHz 38 db
Hum and Noise (65 dBf and 100%
modulation) 70 db
Muting Threshold Adjust to 2 to 20 uv
Audio Output (600 ohm and 47K
Load, 100%Modulation) 1.0 volt
AM Section
Tuning Range 540-1600 KHz
Sensitivity (normal AM)
Long Wire 20 uv
Rod Antenna 200 uvlm
3db AGC Level 200 uvlm
Selectivity
Normal AM (Adjacent Chn) 40 db
Full Fidelity (Alt. Chn) 40 db
Image Rejection (Normal AM) 6 5 d b @ l MHz
IF Rejection (Normal AM) 5 0 d b @ l MHz
Harmonic distortion (Full Fidelity)
30% Mod~~lation 0.5%
90% Modulation 1.5%
Frequency Response + 2db
Normal AM 20-3 KHz
Full Fidelity 20-10 KHz
Hum and Noise (50 KuV/m) 60 db
100%Modulation