Rotel RB-993 User manual
RB-993
THREE-CHANNEL
POWER
AMPLIFIER
Owners
Manual
A
CAUTION
RISK
OF
ELECTRIC
SHOCK
DO
NOT
OPEN
IA
CAUTION:
TO
REDUCE
THE
RISK
OF
ELECTRIC
SHOCK,
DO
NOT
REMOVE
COVER.
NO
USER-SERVICEABLE
PARTS
INSIDE.
REFER
SERVICING
TO
QUALIFIED
SERVICE
PERSONNEL.
APPLICABLE
FOR
USA,
CANADA
OR
WHERE
APPROVED
FOR
TO
THE
USAGE
CAUTION:
TO
PREVENT
ELECTRIC
SHOCK.
MATCH
WIDE
BLADE
OF
PLUG
TO
WIDE
SLOT.
INSERT
FULLY.
ATTENTION:
POUR
EVITER
LES
CHOCS
ELECTRIQUES,
INTRODUCE
LA
LAME
LA
PLUS
LARGE
DE
LA
FICHE
DANS
LA
BORNE
CORRESPONDANTE
DE
LA
PRISE
ET
POUSSER
JUSQU
AU
FOND.
v___
y
A
...
->
WL
This
symbol
is
to
alert
the
user
to
the
presence
of
uninsulated
dangerous
voltages
inside
the
prouct’s
enclosure
that
may
constitute
a
risk
of
electric
shock.
A
l
..
This
symbol
is
to
alert
the
user
to
important
operating
and
maintenance
(service)
instructions
in
this
manual
and
literature
accompanying
the
product.
-j
WARNING:
There
are
no
user
serviceable
parts
inside.
Refer
all
servicing
to
qualified
service
personnel.
WARNING:
To
reduce
the
risk
of
fire
or
electric
shock,
do
not
expose
the
RB-993
to
moisture
or
water.
Do
not
allow
foreign
objects
to
get
into
the
enclosure.
If
the
unit
is
exposed
to
moisture,
or
a
foreign
object
gets
into
the
enclosure,
immediately
disconnect
the
power
cord
from
the
wall.
Take
the
unit
to
a
qualified
service
person
for
inspection
and
necessary
repairs.
Read
all
the
instructions
before
connecting
or
operating
the
RB-993
.
Keep
this
manual
so
you
can
refer
to
these
safety
instructions.
Heed
all
warnings
and
safety
information
in
these
instructions
and
on
the
product
itself.
Follow
all
operating
instructions.
Clean
the
RB-993
only
with
a
dry
cloth
or
a
vacuum
cleaner.
Keep
the
ventilation
inlets
on
the
unit
unobstructed.
For
example,
do
not
place
the
unit
on
a
bed,
sofa,
rug,
or
similar
surface
that
could
block
the
ventilation
slots.
If
the
RB-993
is
placed
in
a
bookcase
or
cabinet,
there
must
be
sufficient
clearance
around
the
unit
and
ventilation
of
the
cabinet
to
allow
proper
cooling.
Keep
the
RB-993
away
from
radiators,
heat
registers,
stoves,
or
any
other
appliance
that
produces
heat.
The
RB-993
must
be
connected
to
a
power
supply
only
of
the
type
and
voltage
specified
on
the
rear
panel
of
the
unit.
Connect
the
RB-993
to
the
power
outlet
only
with
the
supplied
2-pin
polarized
power
supply
cable
or
an
exact
equivalent.
Do
not
modify
the
supplied
cable
in
any
way.
Do
not
attempt
to
defeat
grounding
and/or
polarization
provisions.
The
cable
should
be
connected
to
a
2-pin
polarized
wall
outlet,
matching
the
wide
blade
of
the
plug
to
the
wide
slot
of
the
receptacle.
Do
not
use
extension
cords.
Do
not
route
the
power
cord
where
it
will
be
crushed,
pinched,
bent
at
severe
angles,
exposed
to
heat,
or
damaged
in
any
way.
Pay
particular
attention
to
the
power
cord
at
the
plug
and
where
it
exits
the
back
of
the
unit.
The
power
cord
should
be
unplugged
from
the
wall
outlet
if
the
unit
is
to
be
left
unused
for
a
long
period
of
time.
Immediately
stop
using
the
RB-993
and
have
it
inspected
and/or
serviced
by
a
qualified
service
agency
if:
•
The
power
supply
cord
or
plug
has
been
damaged.
•
Objects
have
fallen
into
or
liquid
has
been
spilled
into
the
unit.
•
The
unit
has
been
exposed
to
rain.
•
The
unit
shows
signs
of
improper
operation
•
The
unit
has
been
dropped
or
damaged
in
any
way
Place
the
RB-993
on
a
fixed,
level
surface
strong
enough
to
support
its
weight.
Do
not
place
the
RB-993
on
a
moveable
cart
that
could
tip
over.
Contents
(circled
numbers
refer
to
illustration)
Figure
1
-
Controls
and
Connections
_
1
Figure
2
-
Wiring
Connections
(RCA
inputs
/speakers)_2
Figure
3
-
Wiring
Connections
(balanced
Inputs)
_2
Getting
Started
_3
A
Few
Precautions
3
Placement
3
AC
Power
and
Control_3
AC
Power
Input
0
3
Power
Switch
0
and
Power
Indicator
0
3
Protection
Circuitry
0
4
Input
signal
connections_4
RCA
Input
Connections
(unbalanced)
0
4
XLR
Input
Connections
(balanced)
0
4
Speakers
_4
Speaker
Selection
4
Speaker
Wire
Selection
4
Polarity
and
Phasing
4
Connecting
the
Speakers
0
5
Troubleshooting_5
Front
Panel
Power
Indicator
Is
Not
Lit
5
Fuse
Replacement
0
5
No
Sound
5
Protection
Indicator
Is
Lit
5
Specifications_5
Figure
3
-
Wiring
Connections
(balanced
inputs)
SURROUND
PROCESSOR
©
©
©
ROTELRB-993
RB-993
Getting
Started
Thank
you
for
purchasing
the
Rotel
RB-993
power
amplifier
When
used
in
a
high-quality
music
or
home
theater
system,
your
Rotel
amplifier
will
provide
years
of
musical
enjoyment.
The
RB-993
is
a
powerful
three-channel
power
amplifier,
ideal
for
driving
the
front
and
center
speakers
in
an
audiophile
quality
home
theater
system.
The
RB-993
provides
the
highest
level
of
au¬
dio
performance.
Discrete
output
devices,
low
negative
feedback,
and
Rotel's
Balanced
Design
ensure
superb
sound
quality.
Its
high
current
capability
allows
the
RB-993
to
drive
the
most
demanding
loudspeakers.
Be
aware
that
the
RB-993
is
capable
of
high
power
levels,
in
ex¬
cess
of
200
watts
per
channel.
Make
sure
that
your
speakers
can
handle
the
power
of
the
RB-993.
If
in
doubt
about
your
speakers,
ask
your
local
Rotel
audio
specialist
for
advice.
The
RB-993
is
straightforward
in
its
installation
and
operation.
If
you
have
experience
with
other
power
amplifiers,
you
shouldn't
find
anything
terribly
perplexing.
Plug
in
three
sets
of
high-quality
RCA
cables
from
your
preamp
into
the
amplifier
inputs,
wire
up
your
speakers,
and
enjoy.
Alternatively,
the
RB-993
provides
an
optional
set
of
"balanced"
inputs
for
use
with
preamps
or
proces¬
sors
that
offer
these
low-noise
XLR-connections.
A
Few
Precautions
Please
read
this
manual
carefully.
In
addition
to
basic
installation
and
operating
instructions,
it
provides
valuable
information
on
various
RB-993
system
configurations
as
well
as
general
informa¬
tion
that
will
help
you
get
optimum
performance
from
your
system.
Please
contact
your
authorized
Rotel
specialty
retailer
for
an¬
swers
to
any
questions
you
might
have.
In
addition,
all
of
us
at
Rotel
welcome
your
questions
and
comments.
Save
the
RB-993
shipping
carton
and
all
enclosed
packing
mate¬
rial
for
future
use.
Shipping
or
moving
the
RB-993
in
anything
other
than
the
original
packing
material
may
result
in
severe
dam¬
age
to
your
amplifier.
Fill
out
and
send
in
the
owner's
registration
card
packed
with
the
RB-993.
Also
be
sure
to
keep
the
original
sales
receipt.
It
is
your
best
record
of
the
date
of
purchase,
which
you
will
need
in
the
event
warranty
service
is
ever
required.
Placement
Because
of
its
high
power
output,
the
RB-993
may
generate
con¬
siderable
heat.
The
heat
sinks
and
ventilation
openings
in
the
am¬
plifier
are
more
than
capable
of
dissipating
this
heat
under
normal
conditions,
but
don’t
smother
your
amplifier.
There
must
be
ad¬
equate
clearance
around
the
chassis.
The
ventilation
slots
in
the
top
cover
must
be
unblocked,
and
there
must
be
reasonable
air¬
flow
around
the
amplifier.
Use
common
sense
when
placing
the
amplifier
in
a
cabinet
or
when
stacking
other
equipment.
Likewise,
remember
the
weight
of
the
amplifier
when
you
select
an
installation
location.
Make
sure
that
the
shelf
or
cabinet
can
support
its
considerable
bulk.
Again,
use
common
sense.
AC
Power
and
Control
AC
Power
Input
Q
Because
of
its
high
power
rating,
the
RB-993
can
draw
consider¬
able
current.
Therefore,
it
should
be
plugged
directly
into
a
2-pin
polarized
wall
outlet.
Do
not
use
an
extension
cord.
A
heavy
duty
multi-tap
power
outlet
strip
may
be
used
if
it
(and
the
wall
outlet)
is
rated
to
handle
the
current
demanded
by
the
RB-993
and
all
the
other
components
connected
to
it.
Be
sure
the
power
switch
on
the
front
panel
of
the
RB-993
is
turned
off
(in
the
"out"
position).
Then,
connect
the
supplied
power
cord
to
the
AC
power
receptacle
on
the
rear
of
the
unit
and
the
AC
power
outlet.
NOTE:
You
may
find
it
convenient
to
use
a
remote
power
control
accessory,
such
as
Rotel's
RLC-900
Line
Conditioner,
to
turn
on
and
off
your
entire
system
automatically
Alternately,
some
pream¬
plifiers
have
a
switched
outlet
that
can
handle
the
current
de¬
mands
of
the
RB-993.
However,
again
be
sure
that
the
switched
outlet
is
up
to
the
task.
Your
RB-993
is
configured
at
the
factory
for
the
proper
AC
line
voltage
in
the
country
where
you
purchased
it
(either
115
volts
AC
or
230
volts
AC
with
a
line
frequency
of
either
50
Hz
or
60
Hz).
The
AC
line
configuration
is
noted
on
a
decal
on
the
back
panel.
NOTE:
Should
you
move
your
RB-993
amplifier
to
another
country,
it
is
possible
to
reconfigure
your
amplifier
for
use
on
a
different
line
voltage.
Do
not
attempt
to
perform
this
conversion
yourself.
Opening
the
enclosure
of
the
RB-993
exposes
you
to
dangerous
voltages.
Consult
a
qualified
service
person
or
the
Rotel
factory
service
department
for
information.
If
you
are
going
to
be
away
from
home
for
an
extended
period
of
time
such
as
a
month-long
vacation,
it
is
a
sensible
precaution
to
unplug
your
amplifier
(as
well
as
other
audio
and
video
compo¬
nents)
while
you
are
away.
Power
Switch
O
and
Power
Indicator
©
The
power
switch
is
located
in
the
center
of
the
front
panel
of
your
amplifier.
To
turn
the
amplifier
on,
push
the
switch
in.
The
LED
indicator
above
the
switch
will
light,
indicating
that
the
ampli¬
fier
is
turned
on.
To
turn
the
amplifier
off,
push
the
button
again
and
return
it
to
the
"out"
position.
NOTE:
If
you
are
using
the
Rotel
RLC-900
AC
Line
Conditioner
or
other
switched
outlet
to
turn
on
and
off
your
amplifier,
you
can
leave
the
power
switch
in
the
"on"position.
3
POWER
AMPLIFIER
RB-993
Protection
Circuitry
Q
The
RB-993
features
a
thermal
protection
circuit
that
protects
the
amplifier
against
potential
damage
in
the
event
of
extreme
or
faulty
operating
conditions.
Unlike
many
designs,
the
RB-993's
protection
circuit
is
independent
of
the
audio
signal
and
has
no
impact
on
sonic
performance.
Instead,
the
protection
circuit
monitors
the
temperature
of
the
output
devices
and
shuts
down
the
amplifier
if
temperatures
exceed
safe
limits.
Most
likely,
you
will
never
see
this
protection
circuitry
in
action.
However,
should
a
faulty
condition
arise,
the
amplifier
will
stop
playing
and
the
LED
indicator
on
the
front
panel
will
light
up.
If
this
happens,
turn
the
amplifier
off,
let
it
cool
down
for
several
minutes,
and
attempt
to
identify
and
correct
the
problem
that
caused
the
protection
circuitry
to
engage.
When
you
turn
the
am¬
plifier
back
on,
the
protection
circuit
will
automatically
reset
and
the
indicator
LED
should
go
out.
In
most
cases,
the
protection
activates
because
of
a
fault
condi¬
tion
such
as
shorted
speaker
wires,
or
inadequate
ventilation
leading
to
an
overheating
condition.
In
very
rare
cases,
highly
re¬
active
or
extremely
low
impedance
speaker
loads
could
cause
the
protection
circuit
to
engage.
If
the
protection
circuitry
triggers
repeatedly
and
you
are
unable
to
isolate
and
correct
the
faulty
condition,
contact
your
Rotel
au¬
dio
specialty
retailer
for
assistance
in
troubleshooting.
Input
Signal
Connections
The
RB-993
gives
you
a
choice
of
two
different
kinds
of
input
con¬
nections
—
conventional
"unbalanced"
RCA
type
connections
(such
as
found
on
nearly
all
audio
equipment)
or
"balanced"
XLR-
type
connections
for
use
with
some
high-end
preamps
or
digital
processors
featuring
this
lower
noise
connection.
NOTE:
You
must
choose
one
or
the
other
type
of
input
connection
—
not
both.
Do
not
connect
both
balanced
and
unbalanced
inputs
simultaneously.
RCA
Input
Connections
(unbalanced)
O
[See
Figure
2
for
wiring
illustration]
When
a
component
with
"RCA"
connectors
—
such
as
a
pream
plifier
or
surround
sound
processor
—
supplies
signals
to
the
RB-993,
the
RCA-type
phono
plug
inputs
should
be
used.
NOTE:
To
prevent
loud
noises
that
neither
you
nor
your
speakers
will
appreciate,
make
sure
the
amplifier
is
turned
off
when
you
make
any
signal
connections.
Select
high
quality
audio
interconnect
cables.
Connect
the
first
output
channel
of
your
preamp
or
surround
processor
to
the
Input
1
"unbalanced"
RCA-connector
on
the
RB-993.
Connect
the
second
output
channel
of
your
preamp
to
the
Input
2
"unbalanced"
connector.
Connect
the
third
output
channel
of
your
preamp
to
the
Input
3
"unbalanced"
connector
on
the
RB-993.
XLR
Input
Connections
(balanced)
O
[See
Figure
3
for
wiring
illustration]
If
you
are
using
one
of
the
few
high-end
preamplifiers
or
proces¬
sors
with
low-noise
"balanced"
signal
outputs
to
drive
your
RB-993,
you
may
choose
to
use
special
XLR-type
connections.
See
your
audio
specialist
for
the
appropriate
cables.
Connect
the
first
output
channel
of
your
preamp
to
the
Input
1
"balanced"
XLR-connector
on
the
RB-993.
When
properly
seated,
the
connector
should
"click"
into
the
connection.
Connect
the
sec¬
ond
output
channel
of
your
preamp
to
the
Input
2
"balanced"
con¬
nector.
Connect
the
third
output
channel
of
your
preamp
to
the
Input
3
"balanced"
connector
on
the
RB-993.
Speakers
Speaker
Selection
We
recommend
using
loudspeakers
with
a
nominal
impedance
of
4
ohms
or
higher
with
the
RB-993.
You
should
exercise
some
cau¬
tion
in
driving
multiple
pairs
of
speakers
in
parallel
configuration,
because
the
effective
impedance
the
amplifier
sees
is
cut
in
half.
For
example,
when
driving
two
pair
of
8
ohm
speakers,
the
ampli¬
fier
sees
a
4
ohm
load.
When
driving
multiple
speakers
in
parallel,
it
is
recommended
that
you
select
speakers
with
a
nominal
imped¬
ance
of
8
ohms
or
higher.
Speaker
impedance
ratings
are
less
than
precise.
In
practice,
very
few
loudspeakers
will
present
any
problems
for
the
RB-993.
See
your
Rotel
audio
specialist
if
you
have
any
questions.
Speaker
Wire
Selection
Use
insulated
two-conductor
stranded
wire
to
connect
the
RB-993
to
the
speakers.
The
size
and
quality
of
the
wire
can
have
an
au¬
dible
effect
on
the
performance
of
the
system.
Standard
18
gauge
"zip
cord"
will
work,
but
can
result
in
lower
output
or
erratic
fre¬
quency
response.
For
wire
runs
of
50
feet
or
less,
we
recommend
16
gauge
or
larger
wire.
For
longer
runs
and
for
optimum
perfor¬
mance,
12
gauge
wire
should
be
used.
For
best
performance,
you
may
want
to
consider
special
high-quality
audio
cables.
Your
local
audio
specialty
retailer
can
help
in
the
selection
of
speaker
cables.
Polarity
and
Phasing
The
polarity
—
the
positive/negative
orientation
of
the
connec¬
tions
—
for
every
speaker
and
amplifier
connection
must
be
con¬
sistent
so
all
the
speakers
will
be
in
phase.
If
the
polarity
of
one
connection
is
mistakenly
reversed,
bass
output
will
be
very
weak
and
stereo
imaging
degraded.
All
wire
is
marked
so
you
can
identify
the
two
conductors.
There
may
be
ribs
or
a
stripe
on
the
insulation
of
one
conductor.
The
wire
may
have
clear
insulation
with
different
color
conductors
4
RB-993
(copper
and
silver).
There
may
be
polarity
indications
printed
on
the
insulation,
Identify
the
positive
and
negative
conductors
and
be
consistent
with
every
speaker
and
amplifier
connection.
Connecting
the
Speakers
Q
[See
Figure
2
for
wiring
illustration]
The
RB-993
has
three
pairs
of
color
coded
binding
posts
on
the
back
panel.
These
connectors
accept
bare
wire,
connector
Jugs,
or
dual
banana
type
connectors
(except
in
the
European
Commu¬
nity
countries
where
their
use
is
not
permitted).
Be
sure
that
you
are
connecting
the
correct
speaker
to
the
de¬
sired
output
For
example,
if
you
have
connected
the
left
channel
signal
to
Input
3
on
the
RB-993,
make
sure
that
you
connect
the
left
speaker
to
the
Speaker
3
terminals,
etc.
Route
the
wire
from
the
RB-993
to
the
speakers.
Give
yourseff
enough
stack
so
you
can
move
the
components
enough
to
allow
access
to
the
speaker
connectors.
If
you
are
using
dual
banana
plugs,
connect
them
to
the
wires
and
then
plug
into
the
backs
of
the
binding
posts.
The
collars
of
the
binding
posts
should
be
screwed
in
all
the
way
(clockwise).
If
you
are
using
terminal
lugs,
connect
them
to
the
wires.
If
you
are
attaching
bare
wires
directly
to
the
binding
posts,
separate
the
first
few
inches
of
the
wire
conductors
and
strip
about
1/2"
of
insulation
from
the
end
of
each
conductor.
Be
careful
not
to
cut
into
the
wire
strands.
Twist
the
strands
of
each
conductor
to¬
gether
to
avoid
fraying.
Unscrew
(turn
counterclockwise)
the
binding
post
collars.
Place
the
connector
lug
around
the
binding
post
shaft,
or
insert
the
bundled
wire
into
the
hole
in
the
shaft.
Turn
the
collars
clockwise
to
clamp
the
connector
lug
or
wire
firmly
in
place.
NOTE:
Be
sure
there
are
no
loose
wire
strands
that
could
touch
adjacent
wires
or
connectors.
Short-circuits
caused
by
loose
strands
touching
will
trigger
the
amplifier
's
protection
circuity
,;
Troubleshooting
Most
difficulties
in
audio
systems
are
the
result
of
poor
or
wrong
connections,
or
Improper
control
settings.
If
you
encounter
prob¬
lems,
isolate
the
area
of
the
difficulty,
check
the
control
settings,
determine
the
cause
of
the
fault
and
make
the
necessary
changes.
If
you
are
unable
to
get
sound
from
the
RB-993,
refer
to
the
suggestions
for
the
following
conditions:
Front
Panel
Power
Indicator
Is
IMot
Lit
No
main
power
to
the
RB-993.
Check
the
front
panel
power
switch.
Make
sure
that
it
is
set
to
the
"on"
position.
Check
AC
power
connections
at
the
amplifier
and
the
AC
outlet.
Fuse
Replacement
Q
If
everything
checks
out
correctly
and
you
still
cannot
get
the
am¬
plifier
to
turn
on,
check
for
a
blown
fuse.
Disconnect
the
AC
from
the
wall
and
remove
the
fuse
holder
on
the
back
panel.
If
the
fuse
is
blown,
replace
with
a
new
fuse,
and
try
again.
NOTE:
Make
sure
that
the
power
cord
is
disconnected
from
the
wall
before
checking
or
replacing
the
fuse.
Replace
only
with
the
identical
size
and
type
fuse
(10
amp
AGCl
No
Sound
tf
the
amp
is
getting
AC
power,
but
Is
producing
no
sound,
check
the
Protection
indicator
on
the
front
panel.
If
it
is
lit,
see
below.
If
not,
check
alf
of
your
connections
and
control
settings
on
associ¬
ated
components.
Check
the
input
selector
switch
on
the
RB-993
back
panel
to
be
sure
that
its
setting
matches
the
type
of
input
you
are
using.
Protection
Indicator
Is
Lit
The
front
panel
indicator
lights
when
the
RB-993
protection
cir¬
cuits
have
shut
off
the
amplifier.
Typically,
this
occurs
only
when
the
ventilation
openings
are
blocked,
when
there
is
faulty
speaker
wiring,
or
after
a
period
of
extreme
use.
Turn
off
the
system
and
wait
for
the
amp
to
cool.
Then
push
the
front
panel
power
switch
in
and
out
to
reset
the
protection
devices.
If
the
problem
is
not
corrected
or
reoccurs,
there
Is
a
problem
with
the
system
or
the
amplifier
itself.
Specifications
Continuous
Power
Output
200
watts/ch
(20-20
kHz,
<
0.03%,
8
ohms)
Total
Harmonic
Distortion
(20
Kz-20
kHz,
8
ohms)
<
0.03%
Intermodulation
Distortion
(60
Hz:
7
kHz.
41)
<
0.03%
Frequency
Response
(+
0.5
dB,
-3
dB)
15-100k
Hz
Damping
Factor
(20-20,000
Hz,
8
ohms)
280
Speaker
Impedance
(Normal
mode)
4
ohms
minimum
Signal
to
Noise
Ratio
(IHF
A
network)
116
dB
Input
Impedance/Sensitivity
32
k
0hms/l
.5
volt
Power
Requirements
115
Volts,
60
Hz
or
230
Volts,
50
Hz
Power
Consumption
600
Watts
Dimensions
(W,
H,
D)
440
x
121
x
365
mm
17.38
x
4.75
x
114.38*
Weight
(net)
18.3
kg,
40.3
lb
All
specifications
are
accurate
at
the
time
of
printing.
Rote!
reserves
the
right
to
make
improvements
without
notice.
5
Table of contents
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