Philips AH673/44 User manual

AH673144 TUNER
PHILIPS HIGH FIDELITY LABORATORIES,LTD.
SIGNAL TUNIN0
AM - LEVEL-F* LEVEL SELECT

INTRODUCTION
You are nowthe proudowner of oneof the finest tuners on the market;the
PhilipsModel 673. This highquality instrumentincorporatesstate of the art
designtechnology and components to giveyou many years of outstanding
performanceand troublefree operation.
Thefront panellayout is simpleand straight forward usingacombinationof
precision.rotary controls and touch switches with LED (Lighting Emitting
Diode)indicators.
f hetouchswitchesprovidesmoothsilentoperationwithout
the "pops" and "clicks" of mechanicalSwitches.The LEDindicator located
above each set of touch contactstells you at a glance which switcheshave
beenactivated.fwoseparateadjustmentsforAMandFM output level provide
you with the ultimate in flexibility and performance. THese variable linear
controlsallow adjustmentfrom
0 - 1 volt for eachoutput.
Thewideview dial scale featuresfinelyetched,precisiongraphics.Thefine
resolution,largeviewing lengthand balancedgraduationsalongwith ahigh
momentumflywheel providefor easy viewing andasmooth,positivetuning
characteristic.
Twotuning metershave beenprovidedas additionaltuning aids.The useof
independentcenter-tuneandsignalstrengthmetersenablesyoutotuneina
stationquicklyandaccurately.At atouchofthefinger,thecenter-tunemeter
becomes a multipath meter. The multipath meter in conjunction with the
signal strengthmeter allowsyou toindependently observe optimum signal
strength and minimum multipath. This will permit adjustment of antenna
orientationfor optimum signal reception. Inaddition tothis convenienttwo
meter approach, horizontal and vertical outputs are available on the rear
panelfor oscilloscopeviewing of multipath.
Full fidelity AM has been incorporated into this tuner for performanceand
response on the AM Band approaching that once thought possible.only
through FMtransmission. Ithas often beenassumedthat the fidelity of AM
would be poor at best, but infact,AM incapableof very goodfidelity, wide
rangeresponseandlowdistortion.Also incorporatedisa
10 KHzsharpnotch
filter which,when activated, considerablyreducesany adjacent channel
10
KHzheterodynewhistlewhenlistenin toAMbroadcasts.TouchtheAutomatic
Stereo Noise Cancelling Switch, A
8 NC, and it activates a unique circuit
whichvirtuallyeliminatestheannoyanceof noisy FMstereobroadcastsand
providesclear receptionof marginallyweak FMstereostations.
The Model and Serial Number of your Philips High Fidelity Laboratories
tunerwillbefoundontherearor bottomoftheinstrument.Pleaserecordthis
Modeland Serial Number inthe space provided below.
Model Number
. Serial Nu~ber
~r9dL73~0~~Cf jg 7 7 3q7-3
WARNING - TO PREVENTDAMAGE WHICH MAY RESULT INFIRE OR
SHOCK HAZARD, DO NOT EXPOSE THIS APPLIANCE TO RAIN OR
EXCESSIVEMOISTURE.

INSTALLATION
LOCATION
Thetunershouldbeplacedas closetoyourothercomponents as isconvenient.
Do not locatethetuner indirect sunlight, near radiatorsor other sources of
heat. Locationshavinghighhumidityor excessivedust should beavoided if
at all possible. If you plan to install the tuner in any type of cabinet or
enclosure,besuretoallowforadequateventilation.Toinsurebestperformance,
takethetimeto preparealocationthat issturdyenoughtosupportthetuner
and itsassociatedcomponents.
ADDITIONAL EQUIPMENT
Any additionalaudio equipmentthat you maywish to purchaseshol-tldbeof
thesame highqualityas this tuner.The Philips
673 iscompatiblewith other
productsfrom Philips High Fidelity Laboratoriesas well as most other high
quality componentequipment.
TUNER CONNECTION
AMPLIFIER
Two pairsof audio output terminals,variable andfixed, are providedonthe
rear of the tuner. Connectthevariableoutput terminalstotheTuner or Aux
inputsof the amplifier using the audio cable which is supplied.'The signal
levelfromthevariableterminalsiscontrolledbythetwolevelcontrolsonthe
frontof thetuner.The Fixedoutput terminals may beconnectedto the Line
Inputterminals of atape deck. Sincethesignal levelfromthe Fixedoutput
terminalscannot beadjustedat thetuner,this must bedonewiththe record
levelcontrolsof thetape deck.
MULTIPATH
The M~tltipathterminals may be connected to the horizontal and vertical
inputs of an oscilloscopefor the purpose of.visually monitoring multipath
distortion. 'This can aid you in positioning the FM antenna for minimum
multipathand maximum signal strength. When operatingthe oscilloscope,
follow the instructionmanual suppliedwith it.
FMDETECTOR OUTPUT
An FMdetector output isavailableonthe back panel,readyfor usewhen 4
channel FM is perfected.
FMANTENNA
A folded dopole FMantenna has been providedwith thistuner.To connect
this antenna, loosenthe two
300 ohm antenna screws,slip the "u" shaped
lugsof theantennaunderthescrewsandtightenthemsecurely.Thecrossbar
of theantennashol-~ldbemountedflat and horizontallyonthewall, alongthe
backedgeof ashelfor otherconvenientlocation.Thisantennaisdirectional;
therefore,discoveringthe best locationmay requiresome experimentation.
Althoughthisantennashouldbeadequatefor receptionof localstations,you
maywish to installan outdoor FMantenna.
Terminalshavebeenprovidedfor theconnectionof
75 ohmcable.Thistype
of antennacablemaybeconnectedbystrippingthe insulationfromoneend

and installingthecableasshown inthe illustration. It mayalso beconnected
tothetuner byfirst installingan
F typescrewonconnectorontheendof the
cable and then attach the cable to the
75 ohm connector of the tuner as
shown inthe connection diagram.
Id
300 OHM
FM ANTENNA
TWIN LEAD
75 OHM
COAXIAL
CABLE
Whenyouinstallanoutdoorantenna,itshouldbeorientedtoprovidemaximum
signalstrengthand minimumreflections.Theantennashouldbeas far away
from roadsand streetsas possiblesince passing cars andtrucks can cause
reflections. By usingthe signal strength and multipathmeters, the correct
antenna positionis indicated by maximum deflection of the signal strength
meterand minimumdeflection of the multipathmeter.
AM ANTENNA
The bar antennamountedon the back of the tuner will providesatisfactory
receptionof localstations.The3dimensionalmountingallowsyoutoposition
the antennato eliminateinterferenceand increasethe signal strength.
- , :>
AM BAR ANTENNA
I I
If you live in an area where satisfactory reception cannot be obtained by
usingthe bar antenna, an outdoor AM antennashould be connectedto the
AM terminal of thetun
r. NOTE: All wires and cables should be
routed away from the
1 M antenna since it is possible for these
wires to introduce
feedback intothe tuner through the antenna.
CONTROLS
-
MASTER POWER
TheMasterPowerswitch,locatedonthebackpanelofthetuner,controlsthe
powerfor allofthecircuitsexcepttheunswitchedAC receptable.'This switch
must be inthe On positionfor the tuner to operate. If the tuner will not be
usedfor anextendedperiodoftime,suchas whenyouareonvacation,place
the Master Powerswitch inthe Off position.

POWER
After placingthe Master Power switch inthe On position,the Power touch
switch on the front panel is used to turn the tuner On and Off. The LED
indicatorabovethetouch contactswill be litwhen the power ison.
FM MULTIPATH
Activating the Multipath switch converts the tuning meter from a center-
tuning meter to a multipath meter for monitoring multipathdistortion. This
enablesyouto adjust the antennafor minimummultipath.
AMIFM LEVEL
The separate Level controls allow you to independently adjust the audio
output for AM and FM.These continuouslyvariable, linearcontrols provide
adjustments of 0 to 1 volt for each output and enable you to balance the
volume levelof the tuner with your other components.
ASNC
The Automatic Stereo Noise Cancelling (ASNC) circuit can be activated
whenlisteningtoanoisyFMstereobroadcast.Thisuniquecircuitsensesthe
amountof noiseinthebroadcast;ifthenoiserisesaboveagiventhreshold,a
Schmitttriggerandaswitchingtransistoractivatethenoisecancellingcircuit
to provideclear reception of marginallyweak stereostations.
NOTE: When
the
ASNC circuit is in operation, it reduces noise on weak stereo stations
without reducingseparation on strong stereo stations.
MUTE
The Mute switch is used in conjunction with the Mute Level control to
eliminateinterstationnoiseas well as weak stations.The thresholdat which
mutingtakesplaceisadjustedwiththe MuteLevelcontrolwhichislocatedto
the rightof the Mute switch. Minimum muting action occurs with the Level
control placed fully counterclockwiseand maximum muting occurs at the
fully clockwise position.
SELECT SWITCH
TheSelectswitchisusedtoselectthedifferentoperationalmodesas follows:
NORMAL- for receptionof AM broadcasts.
FIDELITY
- for reception of AM broadcasts in Full Fidelity. Most
peopleassumethatAM fidelity will bepoorat bestand,
therefore, not worthy of their attention. The medium
of AM is,infact,capableofverygoodfidelity; muchbet-
ter than isusuallythought. Philips'Full FidelityAM cir-
cuits provide a frequency response approaching that
of FM; typically 20
Hz - 10 KHz + 2db with distortion
factor of .5%
@ 30%modulationand 1.5% @ 90%modu-
lation.
STEREOONLY- Perrr~itsreceptionof only those FM stations which are
broadcastinginstereo. Inaddition,interstationnoise is
automaticallymuted.
AUTO- Allows receptionof stereophonic FMand monophonic
FM broadcasts.A stereo broadcast is indicatedbythe
illl~minationof the stereo indicator light locatedtothe
leftof the dial scale.
MONO- In this position all FM broadcasts are reproduced
rnonophonically.
AM 10 KHz
Whenthe10 KHz switchisactivated,asharpnotchbridgeT - LCfilter isintro-
duced intothe IFcircuit to eliminateadjacent channel 10
KHz heterodyne
whistle.

TUNING
The Tuning knobisusedtotune inthe desiredAM and FMstation.
SIGNAL STRENGTH METER
TheSignalStrengthmeterindicatesthe relativestrengthofthestationbeing
received.This meterwillalsoassistyou inproperlyorientingtheantennafor
maximumsignalstrength.
CENTER/MULTIPATH METER
This meter is usedfor preciselytuning tothe center frequency of an AM or
FMradiostation.Turntheturningknobuntiltheneedleisatthecenterof the
scale.
This meter also functions as a multipath meter on FM by activating the
Multipathswitch.Usingthe Multipathmeter,adjusttheantennafor minimum
deflection of the needle.
OPERATION
Before operating the tuner, check to make sure that all connectionshave
beenproperly made andthat power issuppliedtoallof the equipment.
FM RECEPTION
1.
Placethe MasterPowerswitchintheOnposition.Turnthetuneronby
activatingthe Powerswitchonthe front panel.
2. Placethe Select switch inthe Auto position
3.
Turn the Mute off. After you become accustomed to operating the
tuner you may wishtoeliminate the interstationnoise To do thislacti-
vatethe Muteswitch andturnthe Mutelevelclockwiseuntilthe inter-
stationnoiseiseliminated.As the Levelcontrolisturnedfartherclock-
wise, weak stationswill also be muted.
4.
RotatetheTuning knobto locatethe desiredstation.Oncethestation
isfound,observethesignalmeterandadjustthetuningknobfor maxi-
mumdeflectionoftheneedleofthe meter.Completethetuningbyob-
serving the Center-tune meter and adjust the Tuning knob until the
needleiscentered.
5.
Adjust the FM Levelcontrolfor ausefullevel.
AM RECEPTION
1. Turn onTuner.
2.
Placethe~selectswitch inthe Normalor Fidelity position.
3.
Selectthe desiredstation inthe same manner as youwouldselect an
FMstation.
4.
AdjusttheAM Levelcontrolfor a useful level.

TYPICAL
SYSTEM
CONNECTIONS
INDOOR FMANTENNA
LONGWIRE
AM ANTENNA
TUNER INPUT
PREAMPLIFIER

MAINTENANCE
Ifthetunerfailstooperate,checktobesurethattheMasterPowerswitchisin
theOnpositionandthatthetuner isconnectedto an activeoutlet supplying
120 volts, 60 Hz AC. If, after makingthese checks, the tuner still does not
operate; disconnect the line cord from the electrical outlet and check the
fuselocatedonthebackpanel.
If thefuse isblown,replaceonlywitha .5 amp,
125 volt slo-blofuse. Plugthetuner inandturniton. Caution:Ifthetunerfalls
tooperateorthefuseblowsagainafterashorttime,donotattempttoreplace
thefuseagain. Disconnectthelinecordandcontactyourdealeror aqualified
serviceman.Any attempttoreplacethefusewithoneof adifferentvaluemay
constituteafirehazard.
CONTROL PANEL
To cleanthe control panel,disconnect the AC line cord from the electrical
outletanduseacleanlint-freeclothmoistenedwithwarmwateronly.Remove
any excess water beforepluggingthe tuner in.
LAMPS AND INDICATORS
Shouldany of thecontrolpanellampsor function indicatorsburnout,do not
attempttoreplacethemyourself.Referservicingtoaqualifiedserviceman.

TECHNICAL SPECIFICATIONS
(Datasubjectto modificationwithout notice)
FMSection
Tuning Range 87.5
- 108MHz
Antenna Input 300ohm Balanced
75ohm Unbalanced
UsableSensitivity
Mono 1.6 uv
Stereo 3.0 uv
50db Quieting Sensitivity
Mono 2.5 uv
Stereo 32 uv
Total Harmonic Distortion
Mono .12%
Stereo .I 8%
Capture Ratio 1.2db
AM Rejection 50db
IF Rejection 110db
ImageRejection 110db
Spurious Response 110db
Selectivity
(SingleGenerator) >110db
(DualGenerator) 83db
PilotCarrier Suppression 65 db
FrequencyResponse(+.5 -1.5 db) 20-1
5 KHz
Stereo Separation
100KHz 45 db
1 KHz 45 db
10KHz
38 db
Humand Noise (65dBf and 100%
modulation) 70db
MutingThreshold Adjust to
2 to 20 uv
Audio Output (600ohm and 47K
Load, 100%Modulation) 1.0volt
AM Section
Tuning Range 540-1600 KHz
Sensitivity (normalAM)
LongWire 20 uv
RodAntenna 200 uvlm
3dbAGC Level 200 uvlm
Selectivity
NormalAM (AdjacentChn) 40 db
Full Fidelity (Alt.Chn) 40 db
ImageRejection (NormalAM) 65db@lMHz
IFRejection (NormalAM) 50db@lMHz
Harmonicdistortion (Full Fidelity)
30%Mod~~lation 0.5%
90%Modulation 1.5%
FrequencyResponse
+ 2db
NormalAM 20-3 KHz
Full Fidelity 20-10 KHz
Humand Noise (50KuV/m) 60db
100%Modulation