Pioneer SX-424 KUW User manual

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Welcome to the proud family of owners of Pioneer
Hi-Fi equipment! Your new SX-424 AM/FM Stereo
Receiver opens up a whole variety of magnificent
listening experiences including FM stereo reception,
record and tape playing, tape recording, and many
more. You can even use it as a public address sys-
tem for parties and speeches by plugging in a micro-
phone.
FEATURES
FM STEREO TUNER WITH FET-EOUIPPED
FRONT END
The FM tuner's RF amplifier stage is equipped with a field
effect transistor (FET), resulting in higher sensitivity, better
selectivity and image rejection as wel I as greater freedom
from disturbing cross-modulation. The FM MPX (stereo)
decoder circuit operates on the highly accurate,time switch-
ing principle assuring clear-cut stereo channel separation
and high operational stability.
SENSITIVE AM RECEPTION WITH BUILT-IN
FERRITE BAR ANTENNA
An external AM antenna will not be needed in most cases,
because the built-in ferrite antenna assures high sensitivity.
EASY TUNING WITH SIGNAL STRENGTH
METER AND LARGE DIAL
Tuning on both FM and AIVI is quick and accurate, thanks
to the illuminated signal strength meter and the large, linear
(FM) tuning dial.
LINE VOLTAGE AND FUSE
The SX-424 is available in two models: one model operates
only on 120V, and the other either of five line voltages:
110V, 720V, 130V, 220Y and 240V.If your SX-424 is the
latter model, set the unit to the proper line voltage as follows:
CHANGING LINE VOLTAGE SETTING AND FUSE
To remove the fuse, turn the fuse cap located on the line volt-
age selector in the direction of the arrow.
Then remove the fuse plug from the unit. Put the fuse plug
back so that the proper line voltage marking can be seen
through the cut in the edge of the plug Whenever the position
of the selector is changed, check the rating of the fuse. A 1A
fuse is to be used for either 220Y or 240Y operution and a
2A fuse for 110V, 120V or 1-30V operation. If the rating of
the fuse is correct, replace the cap.
FUSE REPLACEMENT
When the fuse blows, remove the fuse cap and replace the
fuse with a new one. See Fig. 1.
Combine the SX-424 with other components of
equally high quality turntable, tape deck,
speakers - study the operating instructions care-
fully, and start off into a whole new world of excit-
ing sound.
CONVERTIBLE INTO A 4-CHANNEL STEREO
SYSTEM
By adding the Pioneer 4-channel decoder amplifier, model
OL-600A and two npre speaker systems the SX-424 can
be upgraded into an ultra-modern "4-channel stereo"
sound system with both matrix and discrete 4-channel
capab ilities.
PROVISIONS FOR ALL COMMON PROGRAM
SOURCES
One turntable, one stereo tape deck and one auxiliary source
(such as a cassette or cartridge tape player, etc.) can be
connected to the SX-424.
ALSO SERVES AS MICROPHONE AMPLIFIER
By connecting a microphone, the SX 424 can be used as a
public address system for speeches, announcements, etc.
STYLED WITH CHARACTERISTIC PIONEER
ELEGANCE
The functional and at the same time attractive metallic
front panel and natural wood cabinet are impressive-looking
and bezutifully matched to the styling of other Pioneer
Hi-Fi components.
corN
Fig. 1

TJIONEEFI
ASSEMBLING A STEREO SYSTEM
Model SX-424 is a Stereo Receiver. To obtain a complete
stereo system, it can be combined with 2 or 4 speaker
systems, 1 turntable, 1 tape deck, etc. See Fig. 2.
With the help of the Pioneer "4-channel decoder" ampli-
fier, model QL-600A and an additional pair of speaker
systems, the SX-424 can serve as the heart of an ultra-
modern 4-channel stereo system. See Fig.3.
INSTALLATION
Do not instali the SX-424 in the following places:
o In direct sunlight or near heating units.
o In damp, dusty places or where air circulation is poor.
o In vibration-prone, unstable places.
CONNECTION AND INSTALLATION
OF SPEAKER SYSTEMS
CONNECTION
o As shown in Fig. 4, connect the lead wires of the speaker
systems to the supplied speaker plugs. Be sure to observe
the correct polarity and to cause no short between @ and
o.
o For the main set of speaker systems, use the A speaker
sockets. Connect the right-channel speaker system to the
socket marked R, and the left-channel speaker system to
the socket marked L.
o For a second set of speaker systems, use the B speaker
sockets. Connect in the same way as for the first set.
NOTE: When using two pairs of speaker systems simultaneously {with the
SPEAKERS switch set to A+B), make sure that the impedance of each
set is at least 8f,1.
INSTALLATION
Optimal stereo effect is obtained when the listener is at one
corner of a regular triangle whose base is the line connecting
the left and right speaker systems (approx. B ft to 8 ft apart).
If at all possible, place the speaker systems at the same height:
a great difference in height affects the stereo effect.
TAPE DECK
CARTRIDGE
TAPF PLAYEB
_--
AM
ANTENNA
o arrooa* sYsrEftns Fig.2
Fig. 3
NEL
ffi
sx-424
A RrcHr
Fig.4

ANTENNA AND GROUND CONNECTIONS
FM ANTENNA
FM broadcast sigr-rals are obstructed somewhat by mountains,
buildings and other obstacles. Therefore, even if a station is
nearby, a high-gain antenna may be required. Select the
antenna in accordance with the following rules:
o If the receiver is to be located in a wooden building and
stations are nearby, use the T-type antenna which comes
with the SX-424. As shown in Fig. 5, connect the feeder
wires of the antenna to the FM antenna terminals.
Stretch out the antenna proper and secure it to the ceiling
or a wall in such a manner that reception is optimum, as
determined by listening to the station to be received. Refer
to FM RECEPTION on page 8.
o If orientation of the T-type antenna does not eliminate
background noise, connect an outdoor antenna to the
antenna terminals shown in Fig. 6. Instead of a special FM
antenna, a combination FM/TV antenna may be used.
NOTES: 1. A variety of FM antennas are available. Consult your deaier.
2. ln locations adjacent to heavily traveled streets, around factories,
or near high voltage power transmission lines, use of an FM antenna
may not give the desired noise attenuation. I n such cases, consult
your dealer concerning a cable feeder (754) for the FM antenna.
When coaxial cable is used. make connection to the receiver as
shown in Fig 7
AM ANTENNA
o Refer to AM RECEPTION on page 8. With an AM station
tuned in, position the ferrite antenna for optimum recep-
tion. See Fig. 8.
. If proper positioning of the ferrite antenna does not give
satisfying results, stretch out the AM lead antenna (vinyt-
insulated wire) and connect it to the AM antenna terminal.
Keep the other end of the antenna lead as high as possible.
r If the lead antenna does not give satisfying results, erect an
outdoor antenna and connect it as shown in Fig. 6. No
special construction is required: vinyl-insulated wire may
be stretched between two masts or other supports.
GROUNDING
o A ground lead is not really required for reception. Still,
from the viewpoint of safety and elimination of noise, one
should be used.
(+)
OUTER
SHIELD
{BRAID)
Fis.5
Strip the end of the
coaxial cable as shown in A.
Loosen the screws shown
in B. I nsert the stripped
end of the coaxial cable.
Tighten the screws. . Fig. 7
FM T.TYPE ANTENNA
AM LEAD
ANTENNA
ECTION OF STATION
AM ANTENNA
XIAL CABLE
Fis.8
:

TJIONEEfiI
BEFORE SWITCHING THE POWER ON
Check that the controls are adjusted as follows:
1. VOLUME control at MIN.
2. MODE switch at STEREO (not pushed).
3. BASS, TREBLE controls at FLAT.
4. TAPE MONITOR switch OFF (not pushed) except for
tape playback.
Now turn the SPEAKERS switch to position A.
FM RECE PTTON
1. Set the SELECTOR switch to FM AUTO.
2. Turn the TUNING knob to tune in the desired station.
Adjust it so that the reading of the SIGNAL meter peaks.
3. When the received progmm is in stereo, the STEREO indi-
cator will iight up. If monophonic, it will not light. If
stereo reception is very weak or noisy, automatic switching
to monophonic reception takes place.
4. Adjust volume and tone with the VOLUME, BASS, and
TREBLE controls.
NOTES: 'l . ln the case of very weak FM stereo signa s, noise wi be nrominent
if the SELECTOR switch is in FM AUTO pos t on To recjuce this
noise, set the SELECTOR switch to FM MONO. Note, however.
that even stereo broadcasts will be received with monophonic
sound.
2" ln some countries, model SX-424 is delivered with a selector
switch for adjusting the FM decmphasis to set either of 5O
and 75 /lsec. If your unit is equipped wilh such a switch
inscribed on the rear of chassis when bottom plate is opened.
And if the high range of sound gives an impression of sharpness
6r hissing, move the de emphasis switch to its other position.
AM RECE PTION
1. Set the SELECTOR switch to AM.
2. Turn the TUNING knob to tune in the desired station.
3. Adjust the VOLUME, BASS and TREBLE controls as
desired.
RECORD PLAYING
1. Make sure that microphone is unplugged into the MIC jack.
2. Set the SELECTOR switch to PHONO/MIC.
3. Start the turntable.
4. Adjust volume and tone with the VOLUME, BASS and
TREBLE controls.

1.
2.
o
USING A MICROPHONE
Plug the microphone into the MIC jack (Fig. 9).
Set the SELECTOR switch to PHONO/MIC.
Adjust the volume by slowly turning up the VOLUME con-
trol. The BASS and TREBLE controls should normally be
set to FLAT.
NOTES: '1 When using a nricrophone, only monophonic sound is heard from
the left and rioht speaker sVSIems.
2 Howling may result if the VOLUME control is turned up too high
or f the nricrophone is too c ose to the speaker systems.
USING A CARTRIDGE TAPE PLAYER
1. Set the SELECTOR switch to AUX.
2. Start the cartridge tape player.
3. Adjust the volume and tone controls as desired.
TAPE RECORDING AND PLAYBACK
RECORDING
As shown in Fig. 10, during playing the signal is always pres-
ent at the TAPE REC jack. Operate the SX-424 as explained
in the sections FM and AM RECEPTION and RECORD
PLAYING on page. 8.
NOTE: The VOLUME. BASS and TREBLE conrrols of theSX 424 do notaf
fect the signa from the TAPE REC jacks. The recordrng level must
be adjusted on the tape deck itself
o TAPE MONiTOR
If the tape deck is a 3-head type or is fitted with a tape
monitor circuit, the recording can be monitored by setting
the TAPE MONITOR switch to ON (pushed). Both recording
and playback connections must be left attached.
PLAYBACK
As shown in Fig. 10, set the TAPE MONITOR switch to ON
for playback of tapes. During playback, volume and tone can
be adjusted by the VOLUME, BASS and TREBLE controls
on the SX-424. Playback is possible regardless of the SELEC-
TOR switch posiLion.
...o I o---
Fis. 9
F is. 10
,,r, ,*rr, I
TAPE
REC
SPEAKER SYSTEM
TAPE DECK
INE OUTPUT
(MONTTOR)
Dtr
S ignal
sx-424
TAPE MONITOR SWITCH

PtoNEefit
A WORD ABOUT ROOM ACOUSTICS
The quality of reproduced sound varies according to the size
and shape of the room, the materials of the walls, floor and
ceiling and the amount and arrangement of furniture. Too
"harsh" or "bright" a sound usually results from too many
hard reflecting surfaces, and/or too low a ceiling. This condi-
tion js improved by having an ample carpeted area or covering
the wall (especially that facing the speaker systems) with a
thick curtain. On the other hand, too many absorbing surfaces
will tend to "soak up" the sound, resulting in a certain "dead-
ness." Furniture may be rearranged to provide irregular reflec-
tion of the sound. In any event, the true stereo effect is lost
if the two speaker systems are placed too far apart. This may
be corrected by angling them slightly toward each other or
reducing the distance between them.
4.CHANNEL STEREO SYSTEM
Conventional 2-channel stereo systems are designed so that
instrumental and vocai music can be reproduced in stereo
through left and right speakers placed in front of the listener.
In contrast, the newly developed 4-channel stereo system
features a high degtee of reproduction of full dimensional
sound including the atmosphere and applause in a concert
hall in addition to stereo sound from singers and instruments.
Consequently, you can get magnificently lifelike 4-channel
sound far superior to that of 2-channel stereo.
The Pioneer 4-channel Decoder Amplifier, model QL-600A
combined with your SX-424, and two additional speakers
gives you 4-channel sound. See Fig.1tr.
HOW TO USE THE 4-CHANNEL DECODER
AMPLIFIER OL-6OOA
To obtain 4-channel sound, combine the Pioneer QL-600A
with your SX-424. The QL-600A has a matrix decoder
circuit for converting a 2-channel stereo signal into a 4-
channel stereo signal plus amplifiers for driving the two
rear speaker systems. As shown in Fig. 12, the eL-600A
can be plugged into the TAPE 2 REC and TAPE 2 MON jacks
of your SX-424, giving you 4-channel sound of the REG-
ULAR or SQ MATRIX type. With the MATRIX system,
matrix recordings or FM stereo broadcasts are reproduced to
perfection. What's more, with a 4-channel stereo tape deck
(Pioneer QT-6600, for example) connected to the eL-600A
as shown in Fig. 12, discrete 4-channel tapes can be re-
produced.
FRONT
LEFT
SI DE RIGHT
SI DE
REAR
CARTR IDGE
TAPE PLAYER
Fis. 11
Fig. 12

CONDITIONS FREOUENTLY MISTAKEN FOR MALFUNCTION
Noise: There are a variety of noises relating to the
operation of a hi-fi unit. These ale generally
divided into two types; (1) the unit is faulty (a
transistor or part has deteriorated) and (2) an
external source is adding to the unit.
When a hi-fi unit produces an unpleasant noise, it is
often assumed that the unit is faulty, but statistical
records indicate that the majority of noises pro-
duced in hi-fi acoustic units result from external
sources of noise: Due to the inherent high
sensitivity and the high fidelity in reproduction,
the unit amplifies and reproduces extraneous
noises, however small, into definite output noise. If
your receiver produces a noise, check according to
the following table and trace out the source of
noise for the appropriate corrective actioil.
SYMPTOM SUSPECTED SOURCE OF NOISE DIAGNOSIS AND REMEDY
F
o
O
o
o
t
c0
o
F
(,
z
=
UJ
F
2
J
z
ul
I
=
Continuous or intermittent
noise like jjjjjj or zzzzzz. Static (lightning)
Fluorescent lamp, motor, or thermostat
may be ln use in house or in the vicinity of
the house.
ln many cases, it is very difficult to remove the source
of noise. ln order to make the radio input larger than
the noise level, set up a good outdoor antenna and
make a complete grounding.
When a station is tuned in,
hum is mixed in the pro-
gram.
Poor fluorescent lamp, motor, or electric
heater may be in use in house or near the
house.
Reversing the line plug may occasionally alleviate this
noise problem. Usually it is very difficult to eliminate
the noise-
Hissing sound noise in AM
(medi um wave ) reception. The frequency of an adjacent station is
interfering with that of the station being
tuned in (10kHz beat interference).
TV set is on in the same house with the
re cei ver.
lmpossible to remove such interference. lf the cause o{
such noise is in the TV set. increase the distance be'
tween the TV set and receiver.
Static noise (in particular,
when automobiles run
close to the house).
" White noise generated from automobile
engines.
. Radio frequency sBwing machine op weld-
ing machine being used near your house.
ln an area surrounded by hills or high buildings, the
FM input signals are very weak. Thus the noise limiter
in the circuit Ioses its function. Set up an FM outdoor
antenna having many director elements.
Reception of FM stereo
program contains more
noise than FM mono pro-
qram.
" Note that the service area covered by an
FM stereo broadcast is about 50% of that
of a regular mono broadcast.
lncreasing FM input signal may alleviate this problem.
Use an exclusive FM outdoor antenna instead of the
indoor T-type antenna.
o
o
t
o
o
uJ
cc
z
;
J
o-
z
ul
I
=
Hum or buzz. When
switched to radio recep-
tion, the noise disappears.
Poor connection of shielded wire (a).
Jack connection is loose. (b).
Line cord or fluorescent lamp is near the
shielded wire. (c).
Poor grounding. (d).
Ham transmitting station or TV transmit-
ting station is near your house. (e).
correct the conditions stated in (a), {b), {c) or {d). In
case of (e). report it to an official activity.
Output tone quality is
poor and mixed with noise
Treble is not clear.
Stylus wears out. (a)
Record wears out. (b)
Dust adheres to stylus. (c)
Stylus is improperly mounted. (d)
Stylus pressure is not proper. (e)
The TRE BLE level is too high.
Check (a) through {e) and correct the condition.
Lower the TREBLE level.
WATCH FOR THE FOLLOWING CONDITIONS; THESE ARE ALSO APT TO BE MISTAKEN FOR MALFUNCTIONS.
SYMPTOM SUSPECTED SOURCE OF NOISE DIAGNOSIS AND REMEDY
Power is not turned on
although the power switch
is set to ON.
Fuse blows. (a)
Line plug is loose. (b) Check (a) and (b) and correct the condition.
ln playing a record, in-
creasing the volume causes
h owlin g.
Distance between the turntable and the
speakers is too short.
The place on which the turntable or
speakers are set is unstable.
Change the distance or rearrange the installation
increase of the unit and speakers. (lnstalling the
turntable on a firm, solid stand may alleviate this
pro ble m. )
Do not enhance the BASS sound level excessively.
1l

TJIONEER
SPECIFICATIONS
SEMICON DUCTORS
F ET(s)
Transistors .....30
Diodes .......24
AMPLIFIER SECTION
Music Power Output (lH F)
Continuous Power Output
(1kHz each channel driven)
Continuous Power Output
( 1 kHz both channels driven)
Harmonic Distortion
I ntermodu lation D istorti on
Power Bandwidth (lHF)
Frequency Response
Speakers
Damping Factor
I nput Sensitivity/l mpedance
Recording Output
BASS Control
TREBLE Control
Equalization Curve
Loudness Contour
Hum and Noise (lHF)
FM TUNER SECTION
Frequency Range
Usable Sensitivity (lH F)
Capture Ratio (lHF)
lmage Rejection
lF Rejection
Spurious Rejection
AM Suppression
Signal to Noise Ratio
Harmonic Distortion
50w (4s})
37W (8{=,)
18W/18W (4O)
14Wl14W (8O)
13W + 13W (4S2)
12W + 12W (8Sr)
Less than 1%
(Continuous Power Output)
Less than 1%
(Continuous Power Output) MISCELLANEOUS
2QHz to 45kHz (8Q, Harmonic power Requirements
Distortion less than 1%)
2OHz to 70kHz, t3dB
4 to 16O
40 (8O, l kHz)
PHONO MAG
MIC
AUX
TAPE MONITOR
180mV/100kO Wei ght (Without package)
TAPE MONITOR (DIN)
180mV/100kO
TAPE REC (Pin Jack) 180mV
TAPE REC (DlN connector)
(With package)
36mV Furnished Parts
-9dB, +9dB/100H2
-9dB, +6dB/10kHz
PHONO: RIAA S.T.D.
+9.5d8/1 00H2, +5.SdB/1 0kHz
with Volume Control set at
-40dB position.
PHONO: More than 75dB
AUX: More than 85dB
88MHz to 108MHz
87.5MHz to 108MHz (FfZap- NorE:
proved)
2.3 ttV
3.5d8
More than 50dB (98MHz)
More than 80dB (90MHz)
More than 70dB (98MHz)
45dB
65dB
Mono: Less than 0.6% (100% Mod.)
Stereo: Less than 0.8% (100% Mod.)
Power Consumption
AC Outlets
3mV/50kf,2 Dimensions (overall)
6.5mV/50kO
180mV/100kfl
Tuning lndicator
Stereo Separation
Sub Carrier Suppression
Antenna lnput
AM TUNER SECTION
Frequency Range
Usable Sensitivity (lH F)
lmage Rejection
lF Rejection
Signal to Noise Ratio
Antenna
Signal strength type
More than 40dB (1kHz)
More than 35dB
lmpedance 300S1 balanced and
75O unbalanced
525kHz to 1,605kH2
15 pV
More than 45dB (1,000kH2)
More than 35dB
More than 50dB
Built-in ferrite bar antenna
120V 60H2, or 110V, 120V,
13OV, 22OV, and 240V.
(Switchable) 50-60H2
90W (Max.)
Switched 1, Unswitched 1.
16-31 132 in. 1431 mm (width)
5 314 in.l146 mm (height)
13-21132 in.1347 mm (depth)
16 lb, 8ozl7.5 kg
17 lb, 6oz17.9 kg (FTZ ap-
proved )
20 lb, 14o219.5 ks
21 lb, 13o219.9 ks (FTZ ap-
proved )
FM T-type Antenna 1
Fuse: 2,A 1
142
(5 line voltage model only)
Protection F uses: 1 .2A 2
(not provided for FTZ-approved
model)
Speaker Plug 4
Polishing Cloth 1
Operating lnstructions 1
Specification and the design subject to possible modifica-
tion wi thout notice due to irnprove.rert5

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