Free Audio Service Manuals - Free download Rotel QA 100 OM

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PRECAUTIONS

To ensure maximum safety, please
carefully follow the instructions be-
low:
1. Check the power source
Plug the unit only into a power
source whose voltage and frequency
ratings match those given in the
instruction manual.
2. Power cord
The.I unit is provided with a 3-core
type a.(:. line cord with a grounding
wire. Insert the plug only into a 3-
conductor outlet (containingground-
ing wire) of 120V/60Hz. Or if a 3-
conductor outlet is notavailable, use
an adaptor, connecting the ground-
ing wire to a grounding screw on a
wall, etc. Insert or unplug the ac.
line cord only after making certain
the units power switch is turned off,
to prevent shock noise from dam-
aging the speakers.
3. Ventilation
To offset heat generated by the
unit, it is necessary to provide
ample ventilation around the unit.
Avoid blocking or impeding the
ventilation holes on the unit. To
prevent unnecessary problems, in-
stall the unit on a place free from
any vibrations, direct sunlight, hu-
midity or dust circulation.
4. Do not open the cabinet
The unit has been completely fear
tory adjusted. To avoid electric
shock or harm to the human body
or to the unit, never open the cabi-
net.
5. II the unit gets wet or foreign
matter amen ,
In case the unit gets wet or any
water or foreign matter gets into
the cabinet, immediately discon-
nect the a.c. line cord, and consult
your dealer or qualified electrician.
8. Instruction manual
Keep the instruction manual near
the unit, and record the serial num-
ber (found on the rear panel) on
the cover.

SWITCHES, CONTROLS AND
OPERATION

(1) Power Button
Depress this button to turn on
power. Pressing it a second time
will turn off power.

(2) Powerlndicator

Glows when the power is turned
on, indicating that the unit is in
operation.

(3) Microphone Jack (MIC 1)
An input terminal used to connect
a high impedance microphone with
standard type plug to the unit. On
the rear panel of the unit are screw-
type MIC 1 terminals. Since the
MIC jack on the front panel takes
priority over the rear MIC termi-
nals, the MIC jack on the front pan-
el should not be connected with a
microphone plug when the MIC 1
terminals on the rear panel are in
use.

(4) MIC 1, 2 Level Controls

These controls regulate the input
levels from microphones connected
to the respective MIC terminals.
Rotate each kgob clockwise to raise
the input level, and counterclock-
wise to reduce it. Turning the knob
1

fully counterclockwise (to position
0") cuts all input from micro-
phone.

(5) AUX Level Control

This knob regulates the level of in-
put from any equipment connected
to the AUX jack on the rear panel,
such as chimes, tape deck, rhythm
box, synthesizer, etc. Rotate the
knob clockwise to raise the level
and counterclockwise to reduce it.
Turning the knob fully counter
clockwise (to position 0") cuts
all input from above equipment.

(6) PHONO/TUNER Level
Control

This knob regulates the level of in-
put from the tuner section of the
unit, or connected record player.
Rotate the knob clockwise to raise
the level of input from the built-in
tuner, and counterclockwise to
raise the level of input from the rec-
ord player. At midposition (0"),
input from either source is cut.

This control operates on either tun-
er or record player, not both at
once; signals cannot be mixed.

(7) MASTER Volume Control
This knob controls at one time the
combined signals coming from Mle
1, 2, AUX, and PHONO/TUNER.
Rotate the knob clockwise to raise
the overall level of those signals to-
gether. and rotate it counterclock-
wise to reduce it. Turning the knob
fully counterclockwise (to "0") po-
sition) cuts all inputs.

Note that this control should be
used at position "5" or higher. If
the master volume control is set
lower than 5", the separate con-

12 13

trols for MIC, AUX or PHONO/
TUNER set higher may cause
"clipping of input signals and
increased distortion in sound.

(8) BASS/TREBLE Tone
Controls

These are rotary controls that regu-
late the balance of tone of input
signals coming from Mle 1, 2,
AUX, or PHONO/TUNEFI. BASS
regulates the low frequency range
and TREBLE the high frequency
range. Rotate the respective knobs
to the right to increase the response,
and to the left to decrease it.

BASS is effective in reducing low-
frequency noise produced by rec»
ord warpage, and TREBLE re-
duces the scratch noise on a record
or the hiss on a tape. Also use these

controls to compensate for acoustic,

conditions.

(9) Tuning Dial

This knob tunes in the desired AM
or FM broadcast station. Use the
lower half of the knob for AM
band, and the upper half for FM
band reception. Rotate the knob to
bring the pointer on the knob to
the desired position on the fre-
quency scale around the knob.
(10)AM/FM Selector

For selecting receiving frequency
bands. Set the selector to AM to rev
ceiva AM stations, and to FM for
FM stations. Set at FM AFC posi-
tion to prevent tuning drift due to
frequency deviation. Generally,
when receiving FM stations, first eat
the selector to FM and tune in to
the desired station; then set the
selector to FM AFC. When not

1415

1718

using the tuner function, turn
selector to OFF.

(11)Ferrite-bar Antenna

This is a built-in antenna for use in
AM broadcast reception. Erect the
bar towards you, and position it
where the reception is optimal.

(12)Antenna Input Terminals
Use the terminals labeled 300m
when parallel feeder is used, and
the terminals labeled 75!} for co~
axial cable. The AM terminal is
used to connect external antenna
when sufficient electric field
strength cannot be obtained with
the built-in ferrite bar antenna.

(13)TUNER Output Jack

This is a tuner output jack for RCA
pin plug. It transmits signal from
the built-in tuner independently,
without mixing, To mute tuner,
short-circuit the jack with shorting
plug.

(14) PRE OUT Terminal

Output from the preamplifier sec-
tion appears at this terminal.

Use this terminal when operating.
units preamplifier section separate-
ly, or when coupling the unit with
separate power amplifier.

(15) MAIN IN Terminal
Terminal for feeding signal into the
units main amplifier section. Use
when operating main amplifier sec-
tion, or when coupling the unit
with separate preamplifier.

(16)Main Amplifier SEPA-
RATE/UNITE Switch

This switch permits either separate
use of main amplifier section or

22»

combined use of main amplifier sec-
tion with preamplifier section. in
SEPARATE position, the main am-
plifier section is disconnected from
the preamplifier section so that you
can used the main amplifier section
separately. In the UNITE position,
the preamplifier and the main am»
plifier sections are connected. In
the UNITE position, the MAIN IN
terminal cannot be used.

(17IPHONO Input Jack

This is a phonograph input termi-
nal for RCA pin plug. When using
stereo phonograph, use Y»adaptor
for RCA plug connection.

Note: The PHONO input jack is for
record player with MM type cart-
ridge. Plug player with ceramic or
crystal cartridge into the AUX jack.

(18IAUX Input Jack

This is an auxiliary input jack for
RCA pin plug.

(19IGND Terminal

This terminal is the connection for
grounding wire of record player,
etc., to reduce inter-equipment
hum noise or induction noise, or to
prevent static electricity.

(20) Music Muting Terminals
Short-circuiting GND and S termi-
nals will immediately cut input sig-
nals at AUX and PHONO/TUNER
(and signal from built-in tuner). Re-
move the short-circuit to regain
state already established by front
panel controls. This function is ef»
fective in interrupting music signals
to insert announcement, etc, by
means of microphones.

(21 ) Microphone InputTerminals

USING RACK MOUNTING
BRACKETS

The unit is mountable into a 19-
inch rack. When rack-mounting the
unit, remove screws near the front
panel at both sides of the cabinet,
and install the rack-mounting
brackets supplied with the screws.
The unit can also be placed in up
right position for wall mounting.
For that purpose, remove screws on
the bottom plate of the unit, and
install suitable brackets with the
screws. '

AMPLIFIER1

70V 12.5V

o MICROPHONE INPUT TERMINAL CONNECTION

MIC-2

MIC-1
BALANCED TYPE, LOW IMPEDANCE (250E)
Length of shielded cord: 200 feet (60 meters) maximum

MIC-2
UNBALANCED TYPE, LOW IMPEDANCE (2509)
Length of shielded cord: 60 feet (18 meters) maximum

MIC-1

o PHONO INPUT JACK CONNECTION WHEN USING STEREO PHONOGRAPH

@ PHONO

These are screw-type microphone
input terminals. The 3 right-hand
terminals are for MIC 1 connec-
tions, and the 3 left-hand terminals
are for MIC 2 connections . Both
MIC 1 and MIC 2 connections can
be made simultaneously. These
terminals have been already adjust-
ed to accept low impedance (250
Ohms) balanced or unbalanced
microphone. The stranded wire
from the microphone should be
hooked up to G terminal.

(22) Speaker Terminals
Unit is provided with 2 sets of
speaker terminals; one for low im-

CONNECTING SPEAKERS IN
SERIES

If two PA music amplifier units are
connected in series, the same
speaker system can be driven with
double power output.

When using 2 units in series, for ex-
ample, set the SEPARATE/UNITE
switch on amplifier "1, which will
be used for source control, to U
NITE position, and set the SEPAR-
ATE/UNITE switch on amplifier
2", whose main amplifier section
alone will be used, to SEPARATE

a-
O

e e
O O

0
50V
(12.59)

70V

t GND

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25V 12 5V
a e
O O

e
O

is
O

AMPLIFIER 2

Y-ADAPTOR

PHONOGRAPH

m
LEW

pedance use, and the other for high
impedance or constant voltage use.
For low impedance use, 0,4, 8, and
16 ohm terminals are available. For
high impedance or constant voltage
use, 0, 12.5, 25, and 70 volt termi»
hole are available.

Terminals are screw-knob type.
Loosen the knob, and the hole
above it will open. Insert the bared
and of speaker cable into the hole,
and than tighten the knob so that
the cable is securely fixed. (Refer
to "CONSIDERATIONS FOR PA
SPEAKER LAYOUT for details on
use of these speaker terminals.)

position. Connect PRE OUT termi-
nal on amplifier "1" to MAIN IN
terminal on amplifier "2" using
RCA pin cord. (See figure for
speaker cable connections in series
combination of amplifiers.)

Note: When amplifiers are connect-
ed in series, the 0V terminal on
amplifier 2" cannot be used as
grounding terminal. Never attempt
to ground the terminal.

(23)Overload Protection Reset
Button

This button resets the built»in pro-
tection device, which would cut the
'0utput when main amplifier sec-
tion is overloaded because of mis«
matching of speaker impedance,
etc. If the protection device is acti-
vated to prevent the unit from
being damaged, remove the cause of
overload, and press the Overload
Protection Reset button to start
normal operation.

AMPLIFIER1 L+
70V 25V 125V 0
140V
0 O O O
>GND
70V 25V
- #_,

93
000

one

AMPLIFIER 2

Rotel QA 100 OM

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