Pioneer SX-939 User manual

STEREO RECEIVER
SX-939
OPERATING
INSTRUCTIONS
YQPIONEER

LINE VOLTAGE AND FUSE AND REAR PANEL
Each design of LINE VOLTAGE and FUSE of this ~
model differs according to each destination to be
delivered.
How to operate the SX-939 is quite the same for
each version. However, each rear panel differs
according to LINE VOLTAGE and FUSE designed
for each version.
Fig. A shows the LINE VOLTAGE of a 220V only
model.
Fig. B shows the LINE VOLTAGE and FUSE of a
5
line
voltage
(110V,
120V,
130V, 220V,
240V)
whose
line
voltage
and
fuse
can
be
changed
and
set
as follows:
The Line VOLTAGE of a 120V only model is
illustrated
Connection
Diagram.
220V model
AC INLET
5
Line
Voltage
mode!
CONTENTS
SX-939 Features .............0000 3
Essentials You should Know.......... 4
Connection Diagram ............... 4
Stereo Setup: ic icecicessececs 6
Speaker Connection ................ 6
Antenna and Ground Connections ..... 7
Connections ......... 0.0000 ee eens 8
CHANGING LINE VOLTAGE SETTING AND
FUSE
To
remove
the
fuse,
tun
the
fuse
cap
located
on
the
line
voltage
selector
in the
direction
indicated
by
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
3A_
fuse
is to
be
used
for
either
220V
or
240V
operation
and
a
6A
rating
for
110V,
120V
or
130V
operation.
If
the
rating
of
the
fuse
is correct,
replace
cap.
FUSE REPLACEMENT
When the fuse blows, remove the fuse cap and
replace the fuse with a new one. Fig. C.
FUSE
FUSE CAP
PHILLIPS (3)
SCREWDRIVER
__...
SOCKET
SP FUSE PLUG
Fig. C
Front
Panel
Facilities...
.............
10
How
to Operate
the Receiver
........
12
Versatile
Jacks
for Today
and
Tomorrow ......... 06. e cece eee 14
Conditions Frequently Mistaken
for Malfunction ...............4. 16
Mounting Template ..............45 17
Specifications .................000. 18

ee
FON
KK
SX-939 FEATURES
FM Front End With Dual-Gate FET’s, Buffer Amp
FM tuner’s sensitivity, overload resistance (ability to receive
very strong signals without distortion), image rejection and
spurious rejection are determined chiefly by the front end.
In the SX-939) latest components and circuit technology
have been employed to bring all these values close to their
theoretical limits: two dual-gate MOS FET’s. RF amplifi-
cation, and the inclusion of a buffer amplifier between local
oscillator and mixer stage. In all performance character-
istics, the SX-939’s FM tuner compares favorably with the
world’s most advanced specialized tuners,
It hardly needs to be mentioned that the FM dial is of
course divided into equal “linear” intervals and that dual
tuning meters — signal strength meter and zero-center meter
—are provided for easy, precise tuning.
Ceramic Filters And IC’s In IF Stages For
Sharp Selectivity
A total of three ceramic filters in the IF (intermediate
frequency) stages give sharp selectivity and never need to be
realigned. Integrated circuits functioning as limiters provide
stable operation and excellent capture ratio (the ability to
distinguish between a wanted and an unwanted signal on
the same station band).
Quadrature Detection, Phase Lock Loop (PLL)
Stereo Demodulator
Detection of the frequency-modulated signal is performed
by the “quadrature” method with a balanced-bridge type
differential amp, This costly design assures linearity
throughout the frequency band and reduces distortion to
the minimum, In the MPX circuit, a phase-lock-loop (PLL)
circuit design is used to give clear, stable separation at any
audio frequency. The circuit is equipped with an IC
(replacing six transistors) in a bridge configuration.
IC Mean Great AM Listening, Too
This section also incorporates integrated circuits and auto-
matic gain control in the RF and IF stages, as well as a
3-ganged variable capacitors for improved image ratio,
selectivity and frequency response, plus reduced distortion.
Balanced Positive And Negative Power Supply
With Heavy-Duty Components
The power supply unit - backbone of any amplifier — is of
the most elaborate type such as used anywhere in home-use
audio equipment, with balanced dual, polarity supply and
extre large10,000uF capacitors. This results in a tremendous
reserve of power for transient peaks, but also eliminates the
irritating switching noise often encountered in less profes-
sional designs.
Phono Equalizer With Wide Dynamic. Range And
Extremely Close Tolerances
The incoming phono signal from a turntable is equalized
precisely according to the international RIAA standard
playback curve — within 0.3 dB of the ideal, Moreover, the
phono inputs can accept relatively strong signal levels
without distortion (250mV rms), resulting in a wide
dynamic range. This is due to the circuit design with three
direct-coupled amplification stages including a differential
amp in the first stage.
Twin Tone Controls Permit Precise
“Shaping” Of Sound
The overall frequency response curve can be controlled in a
total of seven ways. Twin controls in the bass range permit
variation at 100Hz by +10dB in 2dB steps, and at 50Hz by
+5dB in 2.5dB steps; similarly, the high controls give +10dB
correction in 2dB steps at 10kHz, and again +5dB correc-
tion at 20kHz in 2.5dB steps. All tone controls can be
removed from the circuit (by setting the TONE swtich at
OFF) if desired. High and Low filters are provided for
solving specific noise problems, while the Loudness switch
boosts the very low and high frequencies at soft listening
volumes, giving a more natural sound contour, In one word:
the SX-939 gives you complete mastery over what you
hear.
... Plus A Wealth Of Auxiliary Features
And Circuits
Dolby* inputs and outputs permit confection of an
outboard Dolby noise reduction unit, for example, to
receive Dolby-encoded FM programs.
Two tape monitor circuits allow two tape decks to be used
for recording, playback and tape-to-tape duplicating.
Microphone inputs on the front panel let you use the
SX-939 as a public address amplifier.
Audio muting switch decreases the volume instantly by
20dB without having to turn back the volume control,
Indicator lamps light up in accordance with the functions
used, telling you at a glance what you're hearing and how.
Dimmer switch dims illumination of tuning dial, tuning
meters and indicator lamps, leaving only a softly glowing
light in the dark.
*The word ‘Dolby’ is a trademark of Dolby Laboratories Inc.
3

ESSENTIALS
YOU
SHOULD
KNOW
PLACEMENT
OF
YOUR
SX-939
The
SX-939
is
heavy
and
should
always
be
handled
with
great
care.
Equal
care
should
be
given
to
the
choice
of
its
placement
within
your
listening
room.
Once
you
have
chosen
the
best
position,
you
can
proceed
with
connection
of
the
speaker
systems
and
turntable.
Be
sure
to
avoid
the
following
locations,
which
can
cause
malfunctions:
®@
Places
exposed
to
direct
sunlight
or
close
to
heating
units
or
other
sources
of
heat.
@
Places
with
poor
ventilation.
©
Excessively
humid
or
dusty
locations.
©
Sloping
locations,
those
subject
to
vibration,
or
otherwise
unstable.
@
Places
close
to
alcohol
and
spray-type
in-
secticides,
etc.,
or
any
other
such
highly
inflammable
substances.
PROTECTION CIRCUIT
For
some
3
to
6
seconds
after
the
receiver
is
switched
ON,
no
sound
will
be
heard.
This
is
due
to
the
operation
of
protection
circuits
which
are
designed
to
guard
transistors
and
speakers
from
possible
damage
due
chiefly
to
the
switching
transients,
etc.
Should
the
receiver
remain
silent
for
considerably
longer
than
this,
first
switch
off,
and
then
check
the
speaker
system
connections.
Should
the,,receiver
suddenly
go
silent
while
you
are
listening to
it,
if
you
can
hear
a
continuous
series
of
“clicks”
due
to
relay
contacts
opening
and
closing
within
the
receiver,
this
can
be
an
indication
of
a
short
circuit
in
the
speaker
system
connections.
Switch
off,
and
re-check
the
speaker
system
impedances,
etc.
The
protection
circuit
re-sets
itself
automatically,
so
that
normal
functioning
is
resumed
as
soon
as
the
cause
is
removed.
*
The
word
“Dolby”
is
a
trademark
of
Dolby
Laboratories
Inc.
CONNECTION
DIAGRAM
. T-TYPE
FM ANTENNA
FM
DE-EMPHASIS
SWITCH
(5
LINE
VOLTAGE
MODEL
ONLY)
Before
shipment
this
switch
has
been
pre-set
to
the
appro-
priate
position
for
the
delivery
area.
Models
for the
U.S.A.
and
Canada
are
set
to
“75sec”
and
other
models
are
set
to
“BOusec”’.
Incorrect
setting
will
adversely
affect
the
high
sound
range,
so
check
the
position
before
op-
erating
this
unit.
If
you
are
in
doubt
about
the
pre-emphasis
used
in
your
area,
consult
your
audio
dealer.
NOTE:
Be
sure
to
set
the
switch
to
“25usec’”
only
when
receiving
a
special
FM
Dolby”
broadcast
(pre-empha-
sis
25usec)
with
an
auxiliary
Dolby*
NR
adaptor
connected
to
your
system.
OUTDOOR
FM ANTENNE AM ANTENNA
3002
feeder
|
|
|
752
coaxial
cable!
FM OF EMPHASIS
Pout 50 7508
ews
AM
FERRITE
ANTENNA
PRE/POWER
AMP—————
The
bridge/connecting
_ plugs
between
PRE
OUT
and
POWER
IN
jacks
should
always
be
left
in
position
in
normal
use.
If
they
are
disconnected
or
removed,
no
sound
will
come
from
the
speak-
ers,
Always be sure to cut the power
supply before attempting to re-
move them.
As for the applications of the
PRE OUT and POWER IN jacks,
please refer to the section on
PRE OUT AND POWER IN
JACKS on page 9.
er
ee
4

PIONEER
TAPE
DECK
TAPE
DECK
TURNTABLE TURNTABLE
CARTRIDGE
{open-reel,
cassette)
TAPE
PLAYER
—————
——
LINE
Connect
to
OUTPUT
ground
terminal
of
turntables, tape decks,
etc.
Recording
/Playback
cord
DIN-type
For
connecting
4-channel
discrete
FM
adaptor
For connecting
Dolby NR adaptor
SPEAKER SYSTEMS

STEREO
SETUP
Your SX-939 receiver is ideally suited to form the -
heart of a stereophonic reproduction system of
the very highest quality. Use it, as shown in Fig. 1,
with the speaker systems and other components
of your choice, including tumtable, tape deck
(either open-reel or cassette type), etc. The receiver
can also be used as part of the following systems:
@ Multi-amplifier systems.
@ Dolby system reception, playback, and recording.
@ Four-channel playback systems.
@ Four-channel FM multiplex reception.
TAPE DECK
(open-reel or cassette)
TURNTABLE
CARTRIDGE
TAPE PLAYER
+0 Mal Oo
‘SX-939
Vadeod iy MICROPHONES
go
010
080900
0
(8)
SPEAKER SYSTEMS Fig. 1
SPEAKER
CONNECTION
The
receiver
is
equipped
with
three
sets
of
speaker
terminals
(A,
B,
and
C).
Use
the
A terminals
for
the
speakers
in
normal
use.
As shown in Fig. 2 , connect the terminals marked
R
to
the
RH-speaker
systems
(the
speaker
which
is
on
the
right-hand
side
as
viewed
from
the
listening
position), and the terminals marked L to the
LH-speaker systems.
@ As shown in Fig. 3, the upper socket (red) is
the positive (+) terminal, and the lower (black) is
the negative (—) terminal in each case.
In the same way, the speakers, too, have positive
and negative polarity (+ and — terminals).
Be sure to connect terminals of the same
polarity together (+ to +, and — to —).
SPEAKER OUTPUT TERMINALS
RIGHT CHANNEL,
RIGHT SPEAKER LEFT SPEAKER
SYSTEM SYSTEM
Fig. 2
NOTE:
When two sets of speaker systems are being used at the
same time (A+B, A+C, or B+C), please ensure that the
impedance of each speaker system is not less than 8Q. If
speaker systems with impedances below 8 Q are used, the
protection circuit of the receiver may operate to prevent
audition.
Speaker Terminal and Lead-Wire Connections
Connecting
the
leads
(see
Fig.
3
)
1. Depress the black lever on the speaker terminals
and insert the lead from the negative (—) side
into the lower socket hole, and release the lever.
2. Lift up the red lever on the speaker terminals
and insert the lead from the positive (+) side
into the upper socket hole, and then release
the lever.
Speaker lead-wire
10mm.-
Jystiionpe
Remove
insulation
Ss from wire end,
cE
Twist
stranded
wire.
lever
ate
(>)
@
S
lever
Speaker lead -wire
(a)
Fig. 3
Speaker Placement
The optimum stereo effect is obtained from a
two-channel stereo system when the two speaker
systems on the left and on the right are about the
same distance apart as they are from the listener,
forming the three corners of an equilateral triangle.

PIONEER
ANTENNA
AND
GROUND
CONNECTIONS
FM ANTENNA CONNECTIONS
For the best results you should use an outdoor-type
FM antenna. The simple T-type antenna supplied
with the receiver may be satisfactorily used in areas
of high signal strength (for instance, those very
near to the FM station, or in an all-wooden
construction house.)
Placement and Connection of FM Antenna
@ Connect the feeder wire from the antenna to
the FM ANTENNA terminals on the receiver.
@ Please place the antenna for the best reception
while listening to the FM broadcast station as
described in “FM Reception” on page 12.
ANTENNA
TOAUNBAL 3008BAL ao AM ANT
Fig. 4
T-TYPE
Direction
of
OUTDOOR
FM
pao
station ANTENNA
“XN
To FM ANT terminal
Fig. 5
Making
Connections
with
Coaxial
Cable
In certain locations — in cities with high traffic
density,
in
industrial
areas,
and
near
high
voltage
power
lines
—
objectionable
interference
may
be
present even with the use of an outdoor FM
antenna. Please consult with your local audio
dealer on the advisability of connecting the
antenna and receiver with 752 coaxial cable in
place of the feeder you are using. When using
coaxial cable, connections should be made as
shown in Fig. 6.
a
8
A)
Strip
the
coaxial
INNER
cable
as
shown.
CONDUCTOR
©
B) Loosen the screws
and connect the
F
cable.
sarthiee Then tighten all
(BRAIDIE
Nene
en
COAXIAL
CABLE
(75-ohm)
Fig.
6
AM ANTENNA CONNECTIONS
Under normal conditions it will be sufficient to
adjust the ferrite bar antenna mounted on the
rear panel of the receiver for optimum broadcast
signal reception as shown in Fig. 7 and in
accordance with the instructions given on pagel2
“AM Reception.”
Should reception still be noisy or week with the
bar antenna, an indoor lead antenna or special
outdoor AM antenna must be fitted.
Placement and Connection of AM Antenna
© Connect the antenna lead to ‘the receiver AM
ANTENNA terminal.
@ Use vinyl-sheathed wire as shown in Fig. 7
for the indoor lead antenna.
@ For anoutdoor AM antenna, use trees, etc., to
suspend the vinyl-sheathed wire as shown in
Fig. 7.
AM FERRITE ANTENNA
INDOOR AM LEAD ANTENNA OUTDOOR AM ANTENNA
(8)
(c)
To
AM
ANT
terminal
Fig.7
THE GROUND TERMINAL
It is advisable, both on the grounds of safety and
the elimination of interference, to install a ground
wire
wherever
possible.

CONNECTIONS
TURNTABLE CONNECTIONS
The receiver is fitted with two phonograph input
jacks, PHONO 1 and PHONO 2, enabling two
turntables fitted with magnetic phono cartridges
to be connected.
© Connections between the turntable OUTPUT
plugs and the receiver PHONO input jacks
should be made as shown in Fig. 8, taking care
not to confuse L & R channels. If, as in Fig. 8,
the turntable is fitted with a ground lead or
plug, this should be connected to the receiver
GND terminal.
NOTES:
1, When using a turntable fitted with two tonearms, the
output leads for each of the tonearms should be
connected to the respective PHONO input jacks (I
and 2).
2. When using a turntable fitted with a moving coil
(MC) phono cartridge, it is essential to use a special
MC matching transformer or head amplifier.
$X-939’s
PHONO
input
jacks
R CH
TURNTABLE’s output jacks
TAPE DECK CONNECTIONS
The provision of two sets of recording output
jacks (TAPE 1, 2 REC) and two sets of playback
input jacks (TAPE 1, 2 PB) plus a DIN-type
recording/playback connector (TAPE 2 REC/PB)
means that, in addition to normal recording and
playback, two tape decks can be used to record
at the same time, or to “dub” or duplicate
recordings from one tape deck to the other.
Use the connecting cord(s) provided with the tape
deck(s) to make the connections (see Fig. 9).
Thé tape deck can also be connected to the
ADAPTOR jacks (DOLBY NR — noise reduction).
Fig. 8
$X-939's TAPE jacks
LINE
LINE
»
INPUT_OUTPUT
NeUT OUT
ae
input and output jacks Fig. 9
For playback
For
recording
Y
connection
connection
Connections for Recording
@ The receiver output TAPE 1 REC jacks are
connected to the recording input jacks (LINE
INPUT) of the tape deck as shown in Fig. 9.
The upper jacks of each pair are the L (left)
channels and the lower are the R (right) channels.
When the tape deck is provided with a DIN-type
connector for recording and playback, use the
optional recording/playback cord (e.g. Pioneer
model PP-101) to make the connection with
the TAPE 2 REC/PB DIN connector.
NOTE:
If the recording/playback cord connects both recording
and playback at the same time, there is no need to
make separate connections to either TAPE 2 REC output
jacks or TAPE 2 PB input jacks, If the ADAPTOR OUT
jacks are to be used, connect them to the tape deck input
(LINE INPUT) jacks.
@ When using two tape decks, the second tape
deck should be connected to the receiver TAPE
2 REC output jacks. If, however, the first deck
has been connected to the DIN-type recording/
playback connector, the second deck should be
connected to the TAPE 1 REC output jacks.
$X-939's TAPE jacks
DIN-type Recording/Playback cord
(e.g, Pioneer model PP-101)
REC/PB
TAPE
DECK’s
DIN-type
connector
Fig. 10

ee R PIONEER
Connections for Playback
@ Connect the receiver TAPE 1 PB input jacks to
the playback output jacks (LINE OUTPUT or
TAPE MONITOR) on the tape deck. The upper
jacks of each pair are the L (left) channels,
and the lower are the R (right) channels.
NOTE:
If the ADAPTOR IN jacks are to be used, connect
them to the tape deck output (LINE OUTPUT) jacks.
@ When using two tape decks, the second tape
deck should be connected to the receiver TAPE
2 PB input jacks. If, however, the first deck
has been connected to the DIN-type recording/
playback connector (TAPE 2 REC/PB), the
second deck should be connected to the TAPE
1 PB input jacks.
USE OF THE AUX INPUT JACKS
These jacks are a set of spare input jacks. They
can be connected to cartridge tape players,
television sound multiplex tuners, or other forms
of signal output.
The upper of the two terminals is the L (left)
channel, and the lower is the R (right) channel.
USING THE PRE OUT AND POWER IN JACKS
If the connections between the PRE OUT and
POWER
IN
jacks
shown
in
Fig.
11
are
removed,
the power amplifier and pre-amplifier sections can
function separately.
By
isolating
the
receiver
pre-amplifier
section,
it is
possible
to
use
it
to
drive
a
separate,
high
output
power
amplifier
or
to
build
up
a
multi-amplifier
system
as
detailed
here.
Fig. 11
Connections for Setting up A Multi-amplifier
By
purchasing
anelectronic
crossover
network
and
one or two additional power amplifiers, a two- or
three-way multi-amplifier system can be set up.
The multi-amplifier system splits up the audible
frequency range into different frequency bands,
operating amplifiers and speakers ideally suited to
each band. This results in reduced intermodulation
distortion and improved damping and crossover
characteristics. Use of the multi-amplifier system
enables construction of the ideal playback system.
Connections for a two-way multi-amplifier system
are as follows:
1. Remove both of the plugs bridging the PRE
OUT and POWER IN jacks.
2. Connect the PRE OUT jacks to the input jacks
of the crossover network.
3. Connect the POWER IN jacks to the LOW range
jacks of the crossover network.
4, Connect the HIGH range output jacks of the
crossover network to the input jacks of a
separately bought power amplifier for the
high frequency range.
5. Connect the speakers for the lower frequencies
to the receiver, and those for the higher fre-
quencies to the separate amplifier.
The levels of the different frequency ranges are
adjusted at the crossover network. For detailed
instructions on the use of the crossover network,
please refer to the instruction manual provided
with it.
SPEAKER SYSTEMS
$X-939 RIGHT SIDE
TWEETER
CROSSOVER
NETWORK
WOOFER
POWER AMPLIFIER
(HIGH-RANGE)
Fig. 12

FRONT
PANEL
FACILITIES
SPEAKER BUTTONS
Each of speaker systems A, B, and C is connected to each
of output terminals A, B, and C.
By pushing the following:
SPKR-A .... Speaker systems A into operation
SPKR-B .... Speaker systems B into operation
SPKR-C .... Speaker systems C into operation
NOTES:
1. When any two pairs of the buttons (A + B, B+ C,C +A) are
depressed, the corresponding pairs of speaker systems will
come into operation. However, operating all three buttons
even though depressed at the same time is not possible.
2. Only when listening through headphones, press again the
SPKR button(s) in use to OFF (undepressed) from the
ON
position
(pressed)
POWER SWITCH:
Turn
this
switch
ON
but
wait
for
some
3
to
6
seconds,
during
the
silence
of
which
the
protection
circuit
elimi-
nates
the
unpleasant
noise
not
imputed
to
a
receiver
fault,
For
details,
see
“PROTECTION
CIRCUIT”
on
page
4.
PHONES (1, 2) OUTPUT JACKS
Accept
two
pairs
of
headphones.
SIGNAL METER
For AM and FM station tunings.
AM tuning: Tune the dial pointer so that the SIGNAL
meter needle comes to the extreme right.
FM tuning: Both the SIGNAL and FM TUNING
meters work together. The optimum
point of the SIGNAL meter needle is the
same as in AM tuning. Then use the FM
TUNING meter,
BASS CONTROLS
Adjust bass tone quality.
1OOHz
.....
For
the
low
frequencies
below
400Hz.
Possible
up
to
10dB
of
increasing
or
reducing
at
100Hz
in
2dB
steps.
SOH2
=
53
e.
After
adjustment
by
the
100Hz
control,
further
adjust
frequencies
below
80Hz
by
this
control,
if
necessary.
Possible
up
to
5dB
of
increasing
or
reducing
in
bass
response
at
SOHz
in
2.5dB
steps.
LOW CUT, HIGH CUT BUTTONS:
LOW
......
When
the
low-pitched
rumble
(turntable
motor
or
other
source)
is obtrusive,
de-
press
the
LOW
CUT
button
to
ON.
Inno
interference,
leave
it undepressed
(OFF).
HIGH
......
When
the
high
frequency
scratch
noise
(records
or
other
source)
is much,
depress
this
button
to
ON.
In
no
interference,
Icave
it undepressed
(OFF).
TONE SWITCH
When
in
the
ON
(up)
position,
this
switch
causes
the
amplifier
section
to
operate
with
a
flat
frequency
regard-
less
of
the
tone
control
settings.
Use
this
switch
to
check
the
audio
characteristics
of
your
listening
room
such
as
when
it
is
necessary
to
check
the
tone
quality
of
phono
cartridges
and
speakers
and
also
to.particularly
set
the
tone
controls
to
be
assessed,
TS
SE
I
10
TREBLE
CONTROLS:
Adjust
treble
tone
quality.
10KHz
.....
For
the
high
frequencies
above
2.5kHz.
Possible
up
to
10dB
of
increasing
or
reducing
in
treble
response
at
10KHz
in
2dB
steps.
20KHz
.....
After
adjustment
by
the
10kHz
control,
further
adjust
frequencies
above
12kHz
by
this
control,
if
necessary.
Possible
up
to
SdB
of
increasing
or
reducing
in
treble
response
at
20k
Hz
in
2.5dB
steps.
AUDIO
MUTING
BUTTON
—20dB
Depress
this
button
to
mute
the
audio
input
to
—20dB.
No
need
to
turn
down
the
VOLUME
control
on
each
occasion
for
your
convenience.
TAPE DUPLICATE SWITCH
Leave this switch in the ON (down) position to duplicate
or edit a recorded tape using two tape decks. For normal
use, switch over to the OFF (up) position.