NAD 2600 User manual
NAD)
2600
POWER
AMPLIFIER
MONITOR
SERIES
INSTRUCTIONS
FOR
INSTALLATION
AND
OPERATION
A
NOTE
ON
INSTALLATION
This
unit
may
be
installed
on
any
sturdy,
level
surface.
Since
its
power
transformer
generates
a
magnetic
hum
field
of
moderate
strength,
a
turntable
(especially
one
with
a
moving-coil
pickup
cartridge)
should
not
be
located
directly
to
the
left
of
the
amplifier
nor
directly
above
it.
The
amplifier
generates
a
modest
amount
of
heat
and
thus
requires
some
ventilation.
Do
not
place
it
on
a
rug
or
other
soft
surface
that
it
could
sink
into,
obstructing
the
air
inlets
on
its
bottom.
And
be
careful
not
to
obstruct
the
air
outlet
grille
on
the
top
cover.
CAUTION:
To
prevent
a
fire
or
shock
hazard,
do
not
permit
liquid
or
moisture
to
enter
the
amplifier.
If
liquid
is
accidentally
spilled
on
it,
immediately
shut
off
its
power
and
unplug
its
AC
power
cord.
Allow
sufficient
time
for
complete
evaporation
to
occur
before
operating
the
amplifier
again.
(If
the
liquid
is
anything
but
water
and/or
alcohol,
the
amplifier
should
be
examined
by
a
service
technician
before
power
is
applied
to
it.)
Do
not
open
the
amplifier,
or
attempt
to
modify
or
repair
it
yourself.
Refer
all
servicing
to
a
qualified
technician.
REAR
PANEL
CONNECTIONS
1.
AC
LINE
CORD
Plug
the
AC
line
cord
into
a
nearby
wall
outlet
that
provides
the
correct
AC
power
line
voltage.
If
you
must
use
an
AC
extension
cord,
it
should
be
a
heavy-duty
(14
or
16
gauge)
cord.
You
may
plug
the
power
amplifier
into
a
“switched”
AC
outlet
on
your
preamplifier,
and
use
the
preamp’s
Power
switch
to
turn
the
entire
system
on
and
off.
But
this
is
recommended
ONLY
IF
the
preamp’s
AC
switching
is
rated
to
handle
this
amplifier’s
maximum
power
consumption
(700
watts).
The
preamplifier’s
power
switch
should
be
rated
to
handle
a
turn-on
surge
current
of
at
least
10
amperes.
If
your
preamplifier
was
not
designed
for
high-current
power
switching,
the
practical
alternative
is
to
connect
the
preamp
and
power
amp
to
a
“power
strip”
containing
several
AC
outlets,
and
use
its
heavy-duty
switch
to
turn
your
system
on
and
off.
2.
AC
LINE
FUSE
(Only
in
220V,
240V
Models)
Prolonged
operation
at
excessively
high
power
levels
could
cause
this
line
fuse
to
blow.
If
this
occurs,
the
amplifier
will
not
operate,
and
the
Power
LED
on
the
front
panel
will
remain
dark.
In
this
case,
unscrew
the
fuse
holder
and
install
anew
5-ampere
fuse.
If
the
second
fuse
blows,
return
the
amplifier
for
service.
3.
SPEAKER
IMPEDANCE
The
impedance
of
a
loudspeaker
varies
with
frequency,
and
in
many
loudspeakers
the
impedance
is
lowest
at
the
frequencies
where
the
highest
power
demands
occur
in
music.
In
many
“8Q”
loudspeakers
this
minimum
impedance
is
from
4
to
6
ohms.
And
if
you
connect
two
pairs
of
8-ohm
speakers
to
the
amplifier
the
nominal
impedance
of
the
combination
is
4
ohms.
For
these
reasons,
all
NAD
amplifiers
and
receivers
are
designed
to
produce
maximum
power
output
into
a
4-ohm
impedance,
and
4Q
is
the
Normal
setting
of
the
Impedance
selector.
If
you
are
not
sure
of
the
true
impedance
of
your
speakers,
leave
the
Impedance
switch
at
40
(NORMAL).
If
you
are
using
a
single
pair
of
loudspeakers
whose
impedance
is
8
ohms
or
higher,
you
can
optimise
the
amplifier
for
maximum
power
delivery
at
this
higher
imped-
ance
by
re-setting
the
switch
to
8Q
(HIGH).
NOTE:
The
power
must
be
switched
off
whenever
the
Impedance
switch
is
operated
(reset
from
8
to
4
or
vice
versa).
To
prevent
accidental
re-setting,
the
impedance
switch
is
recessed
within
a
slot
in
the
rear
panel.
Use
the
tip
of
a
small
screwdriver
to
slide
the
switch
down
to
the
8Q
(HIGH)
position.
CAUTION:
If
the
impedance
switch
is
set
to
8Q
(HIGH)
with
loudspeakers
whose
true
impedance
is
lower
than
6
ohms,
or
with
two
pairs
of
speakers
connected
in
parallel,
the
amplifier
will
tend
to
overheat
and
shut
down when
operated
at
high
output
levels.
The
amplifier
will
resume
normal
operation
after
it
cools;
but
such
abuse
could
also
cause
internal
fuses
to
blow
in
order
to
protect
the
amplifier.
if
this
occurs,
return
the
amplifier
to
your
dealer
for
service.
4.
SOFT
CLIPPING
When
an
amplifier
is
overdriven
beyond
its
specified
.
power
output
it
normally
produces
“hard
clipping”
of
the
signal
with
harsh
distortion
and
power-supply
buzz
as
the
output
transistors
saturate.
The
NAD
Soft
Clipping
circuit
gently
limits
the
output
waveform
and
minimizes
audible
distortion
when
the
amplifier
is
overdriven.
If
your
listening
involves
moderate
peak
power
levels,
the
Soft
Clipping
may
REAR
PANEL
CAUTION
RUS
1.
AC
Line
Cord.
5.
Speaker
terminals.
2.
AC
Line
Fuse
(220V,
240V
Models
Only).
6.
Inputs
(Normal
and
Lab).
CAUTION:
TO
REDUCE
3.
Speaker
Impedance.
7.
Bridging.
SHOGR
HO
NOT
REMOVE
4.
Soft
Clipping.
NO
OSER
SERVIGEABLE
PARTS
INSIDE.
REFER
SERVICING
TO
QUALIFIED
SERVICE
PERSONNEL
LEFT
(MONO)
SOFT
CLIPPING
8~
16M
(HIGH)
EEE)
ce
RISQUE
DE
CHOC
IMPEDANCE
(-)
RIGHT
+
+
verri—|
ELECTRIQUE-
4~80
(NORMAL)
NE
PAS
OUVRIR
NOTE:
use
THE
4~8n
POSITION
WHEN
OPERATING
THIS
AMPLIFIER
IN
BRIDGED
MODE.
_
GAUTION
|
iN
Se
ee
RISK
OF
ELECTRIC
SHOCK
POSITION
4~8n
{-}
MONO
+
DO
NOT
OPEN
EST
OBLIGATOIRE.
FRONT
PANEL
1.
Power.
4.
Protection
Indicator.
2.
Input
Level.
5.
Overload
Indicator.
3.
Soft
Clipping
Indicator.
Monitor
Series
Power
Amplifier
2600
POWER
ENVELOPE
PROTECTION
eae
OVERLOAD
LEFT
INPUT
RIGHT
NOTE:
Some
NAD
components
are
equipped
with
dual
or
multi-voltage
transformers
(which
is
indicated
on
the
back
panel).
If
you
wish
to
change
the
voltage,
please
bring
your
unit
to
an
authorized
NAD
service
technician
for
in-
ternal
conversion.
CAUTION:
TO
PREVENT
ELECTRIC
SHOCK
DO
NOT
USE
THIS
(POLARIZED)
PLUG WITH
AN
EXTENSION
CORD,
RECEPTACLE
OR
OTHER
OUTLET
UNLESS
THE
BLADES
CAN
BE
FULLY
INSERTED
TO
PREVENT
BLADE
EXPOSURE.
The
lightning
flash
with
arrowhead,
within
an
equilateral
The
exclamation
point
within
an
equilateral
triangle
is
intended
triangle,
is
intended
to
alert
the
user
of
the
presence
of
to
alert
the
user
of
the
presence
of
important
operating
and
uninsulated
“dangerous
voitage”
within
the
product's
encio-
maintenance
(servicing)
instructions
in
the
literature
sure;
that
may
be
of
sufficient
magnitude
to
constitute
a
accompanying
the
appliance.
risk
of
electric
shock
to
persons.
be
left
OFF.
But
we
recommend
that
it
be
switched
ON
when
playing
music
at
very
high
levels
that
might
exceed
the
amplifier’s
power
capacity.
5.
SPEAKER
TERMINALS
The
amplifier
is
equipped
with
special
high-current
binding-post
speaker
terminals
to
handle
the
highest
peak
power
levels
that
may
occur
in
the
“bridged”
mode
or
with
low-impedance
speakers.
Connect
the
loudspeakers
with
heavy-duty
(16-gauge
or
thicker)
stranded
wire.
Heavy-duty
wiring
is
especially
desirable
if
you
are
using
speakers
of
low
impedance
or
two
pairs
of
speakers
wired
in
parallel.
Each
binding
post
consists
of
a
threaded
metal
shaft
and
a
plastic
screw-on
bushing.
Connections
may
be
made
in
either
of
two
ways:
(1)
A
lateral
opening
in
the
base
of
each
terminal
accepts
bared
wires
up
to
14
gauge
in
thickness.
Separate
the
two
conductors
of
the
cord,
and
strip
off
about
a
half-inch
(1
cm)
of
insulation
from
each.
In
each
conductor,
twist
together
the
exposed
wire
strands.
Unscrew
the
colored
plastic
bushing
a
few
turns,
insert
the
wire
into
the
hole
in
the
base
of
the
terminal,
and
screw
the
bushing
down
tight
until
it
grasps
the
wire
and
holds
it
securely.
Connect
the
wires
from
the
left-channel
speaker
to
the
(L+)
and
(L—)
terminals
and
the
wires
from
the
right-
channel
speaker
to
the
(R+)
and
(R—)
terminals.’Check
to
be
sure
that
no
loose
strand
of
wire
is
touching
any
ad-
jacent
terminal
or
the
amplifier
chassis.
(2)
A
spring-type
banana
plug
may
be
inserted
axially
into
the
end
of
each
binding
post.
The
binding
posts
have
the
¥4-inch
(19
mm)
spacing
required
to
accept
standard
dual-
banana
plugs.
Purchase
dual-banana
plugs
and
install
them
on
your
speaker
cables
(or
purchase
speaker
wires
with
dual-banana
plugs
already
installed),
and
plug
them
into
the
binding-post
terminals.
If
you
want
to
connect
two
pairs
of
loudspeakers
in
parallel,
you
may
use
both
methods.
Connect
your
main
speakers
permanently
via
the
opening
at
the
base
of
each
binding
post,
and
use
dual-banana
plugs
for
the
second
pair
of
speakers.
Then
the
second
pair
of
speakers
can
be
con-
nected
and
disconnected
easily
when
desired.
CAUTION:
TO
AVOID
THE
RISK
OF
SHOCK,
MAKE
SURE
THAT
WHEN
CONNECTING
SPEAKERS
THERE
IS
NO
EXPOSED
BARE
WIRE
WHICH
MIGHT
BE
CONTACTED.
Phasing.
Stereo
speakers
must
operate
in
phase
with
each
other
in
order
to
yield
a
good
stereo
image
and
to
reinforce
rather
than
cancel
each
other’s
output
at
low
frequencies.
If
your
speakers
are
easily
moved,
their
phasing
can
easily
be
checked.
Make
the
connections
to
both
speak-
ers,
place
the
speakers
face-to-face
only
a
few
inches
apart,
play
some
music,
and
listen.
Then
swap
the
connection
of
the
two
wires
at
the
back
of
ONE
of
the
speakers,
and
listen
again.
The
connection
which
produces
the
fullest,
boomiest
bass
output
is
the
correct
one.
Connect
the
wires
securely
to
the
speaker
terminals,
being
careful
not
to
leave
any
loose
strands
of
wire
that
might
touch
the
wrong
terminal
and
create
a
partial
short-circuit;
then
move
the
speakers
to
their
intended
locations.
Ifthe
speakers
cannot
easily
be
set
face-to-face,
then
phasing
must
rely
on
the
“polarity”
of
the
connecting
wires.
The
speaker
terminals
on
the
amplifier
are
labeled
(+)
and
(-)
in
each
channel.
The
terminals
at
the
rear
of
the
speakers
are
also
marked
for
polarity,
either
via
red
and
black
connectors
or
by
labels:
“+”,
“1”,
or
“8”
ohms
for
positive,
“-”,
“0”,
or
“G”
for
negative.
As
a
general
rule
the
red
(+)
terminal
on
the
amplifier
is
to
be
connected
to
the
red
(positive)
terminal
of
the
speaker,
in
each
channel.
To
facilitate
this,
the
two
conductors
comprising
the
speaker
wire
in
each
channel
are
different,
either
in
the
color
of
the
wire
itself
(copper
vs.
silver)
or
in
the
presence
of
a
small
ridge
or
rib
pattern
on
the
insulation
of
one
conductor.
Use
this
pattern
to
establish
consistent
wiring
to
both
speak-
ers
of
a
stereo
pair.
Thus
if
you
connect
the
copper
colored
wire
(or
ribbed
insulation)
to
the
(+)
amplifier
terminal
in
the
Left
channel,
do
the
same
in
the
Right
channel.
At
the
other
end
of
the
wire,
if
you
connect
the
copper
colored
wire
(or
the
ribbed
insulation)
to
the
red
or
positive
terminal
on
the
left-channel
speaker,
do
the
same
at
the
right-
channel
speaker.
6.
INPUTS
(Normal
and
Lab)
Before
making
or
changing
input
connections
to
the
power
amplifier,
make
certain
that
its
Power
is
switched
OFF.
Connect
the
signal
cable
from
your
preamplifier
either
to
the
NORMAL
input
jacks
or
to
the
LAB
input
jacks.
The
NORMAL
inputs
contain
minimum-phase
infra-
sonic
and
ultrasonic
filters,
whose
purpose
is
to
remove
non-musical
signals
at
frequencies
below
10
Hz
and
above
40
kHz
(due
to
turntable
rumble,
disc
warps,
radio-frequency
interference,
tracing
distortion,
etc).
These
inputs
should
be
used,
especially
if
your
preamplifier
lacks
such
filtering.
The
LAB
inputs
bypass
these
filters,
providing
extended
response
at
infrasonic
and
ultrasonic
frequencies.
7.
BRIDGING
This
switch
“bridges”
the
two
power
amplifier
channels
to
form
a
monophonic
amplifier
with
more
than
double
the
output
power.
To
convert
to
bridged
operation,
the
following
procedure
should
be
followed.
(1)
Switch
OFF
the
POWER.
(2)
Be
sure
that
the
IMPEDANCE
switch
is
set
to
40
(NORMAL).
If
it
is
at
8Q
(HIGH),
re-set
it
to
4Q
(NORMAL).
NOTE:
In
the
bridged
mode
the
loudspeaker’s
imped-
ance
is
effectively
halved
as
“seen”
by
the
amplifier.
An
8-ohm
load
looks
like
4
ohms,
a
4-ohm
load
looks
like
2
ohms,and
pairs
of
4-ohm
speakers
operated
in
parallel
will
look
like
a
1-ohm
load.
Driving
paralleled
low-impedance
speakers
to
high
levels
will
cause
the
amplifier
to
overheat
and
shut
down,
or
may
cause
internal
fuses
to
blow
in
order
to
protect
the
amplifier.
For
best
results
the
bridging
mode
should
be
used
with
a
single
8-ohm
or
higher
impedance
speaker
in
each
channel.
In
either
case,
the
Impedance
switch
should
be
set
to
4
ohms.
(3)
Disconnect
any
signal
cables
from
the
input
jacks.
Decide
whether
this
amplifier
will
be
driving
the
Left
or
Right
speaker.
Connect
the
corresponding
(left
or
right)
signal
cable
from
your
preamplifier
to
one
of
the
L
input
jacks
of
this
amplifier
(either
LAB
or
NORMAL,
as
you
prefer).
In
the
bridged
mode
the
amplifier
is
driven
only
through
its
L
(Left)
input,
and
the
volume
is
adjusted
with
the
Left
input
control,
even
though
it
may
be
connected
to
the
“Right”
speaker.
If
another
NAD
2600
amplifier
in
bridged
mode
is
used
for
the
second
stereophonic
channel,
it
also
will
be
driven
through
an
L
input,
regardless
of
whether
it
is
used
to
drive
the
Left
or
Right
loudspeaker.
(4)
Disconnect
any
wires
from
the
SPEAKERS
termi-
nals.
Select
the
wire
from
the
speaker
that
will
be
driven
by
this
bridged
amplifier.
Connect
its
“positive”
conductor
to
the
L+
terminal
and
its
“negative”
conductor
to
the
R+
terminal
(i.e.
the
two
red
terminals).
DO
NOT
connect
any
wires
to
the
black
terminals
(L—
and
R—).
CAUTION:
In
the
bridged
mode
the
speaker
wires
must
be
“floating”
with
respect
to
the
circuit
ground.
Do
NOT
connect
the
speaker
wires
to
anything
that
shares
a
common
ground
between
stereo
channels
(such
as
some
speaker
switches
or
adapters
for
electrostatic
headphones),
nor
to
any-
thing
which
shares
a
common
ground
with
the
amplifier's
inputs
You
can
use
the
input-level
controls
to
correct
these
fixed
(such
as
a
switching
comparator
or
a
distortion
analyzer).
(5)
After
the
preceding
conditions
have
been
satisfied,
re-set
the
Bridging
switch.
It
is
held
in
place
by
a
plastic
bracket
fastened
by
two
screws.
Use
a
small
screwdriver
to
loosen
the
bracket
screws,
turning
each
about
a
half-
turn
counterclockwise;
then
slide
the
switch
to
ON
(MONO).
The
bracket
will
move
with
the
switch.
Re-tighten
the
screws
to
secure
the
switch
in
its
new
position.
Finally,
turn
the
power
on.
(6)
To
return
the
amplifier
to
normal
stereo
operation
at
a
later
date,
first
turn
off
the
power.
Loosen
the
bracket
screws,
re-set
the
Bridging
switch
to
OFF
(STEREO),
and
tighten
the
bracket
screws
to
prevent
the
switch
from
being
moved
acci-
dentally.
Restore
normal
Left
and
Right
input
connections,
and
re-connect
loudspeaker
wires
to
the
speaker
terminals
as
described
above
under
SPEAKERS.
FRONT
PANEL
CONTROLS
1.
POWER
Press
the
Power
button
to
turn
on
the
amplifier.
The
green
LED
glows
when
the
power
is
on.
Press
the
Power
button
again
to
switch
the
amplifier
off.
2.
INPUT
LEVEL
The
amplifier
is
equipped
with
separate
input
level
controls
for
the
two
channels.
Normally
both
controls
should
be
turned
to
maximum.
But
there
are
several
circumstances
in
which
reduced
settings
may
be
useful:
(1)
Level-Matching.
!n
a
multi-amplifier
system,
use
these
controls
to
match
the
output
of
this
amplifier
to
others
in
the
system.
(2)
Extended
Volume-Control
Range.
Many
stereo
sys-
tems
have
so
much
voltage
gain
that
the
speakers
(or
your
ears)
are
over-driven
at
any
preamplifier
Volume-control
setting
higher
than
11
or
12
o’clock.
As
a
result
you
are
confined
to
using
only
the
lower
half
of
the
Volume
control's
range,
where
adjustments
are
imprecise
and
where
most
Volume
controls
produce
channel-balance
errors.
The
solution
is
to
turn
the
power
amplifier’s input-level
controls
down
part-way
(to
about
1
o'clock,
for
example)
in
each
channel.
Now
you
can
turn
up
your
preamplifier’s
Volume
control
further,
making
effective
use
of
most
of
its
range.
(Suggestion:
adjust
the
power
amplifier’s
input
level
controls
so
that
your
preferred
maximum
sound
levels
usu-
ally
occur
at
about
2
or
3
o’clock
on
your
Volume
control.)
As
an
added
benefit,
this
procedure
suppresses
any
noise
produced
by
the
preamp’s
high-level
circuitry
(e.g.
any
residual
hum
or
hiss
that
does
not
go
away
when
the
Volume
is
turned
down).
(3)
Balance
Correction.
Small
errors
in
channel
balance
can
dramatically
degrade
the
apparent
“depth”
and
“air”
of
the
stereo
image.
Such
balance
errors
may
be
due
to
normal
production-line
differences
in
speaker
sensitivity,
differences
in
the
acoustic
environment
around
the
two
speakers,
and
slightly
different
distances
from
your
chair
to
each
speaker.
balance
errors,
freeing
your
preamplifier’s
balance
control
to
correct
balance
errors
in
recordings.
Switch
the
preamp
to
mono
and
sit
in
your
normal
listening
location.
Ideally
the
“phantom”
central
image
should
seem
to
be
floating
in
mid-air
halfway
between
the
left
and
right
speakers.
If
it
is
located
off-center,
closer
to
one
speaker,
turn
down
the
input-level
control
for
that
chan-
nel
slightly
in
order
to
center
the
phantom
mono
image.
Then
restore
the
preamp
to
normal
stereo
operation.
If
you
have
turned
the
input-level
controls
down
part-way
to
adjust
the
overall
volume
level,
do
this
balance
correction
as
the
final
step.
NOTE:
In
bridged
mode,
the
volume
is
adjusted
with
the
Left
input
level
contro!
only.
3.
SOFT
CLIPPING
INDICATOR
This
amber
LED
glows
when
the
Soft
Clipping
switch
(on
the
rear
panel)
is
ON.
4.
PROTECTION
INDICATOR
The
amplifier
can
safely
and
cleanly
drive
impedances
as
low
as
2
ohms
with
wide-range
musical
signals
whose
peak
level
is
500
watts
or
more.
But
if
called
upon
to
de-
liver
high
power
continuously
into
a
low
impedance,
the
output
transistors
may
overheat.
In
this
case,
protection
relays
will
automatically
disconnect
the
speakers
and
the
PROTECTION
light
will
illuminate.
If
this
occurs,
switch
off
the
Power.
When
the
output
stage
cools,
the
relays
will
automatically
re-connect
the
speakers,
and
normal
operation
can
be
resumed.
In
most
cases
a
very
slight
reduction
in
volume
level
will
prevent
further
interruptions
in
the
sound.
If
the
protection
relays
interrupt
the
sound
frequently,
several
possible
causes
should
be
considered:
a
loose
strand
of
wire
causing
a
partial
short-circuit
between
speaker
terminals,
or
continuous
high-power
operation
into
a
very
low
impedance
in
the
Bridged
mode,
or
any
obstruction
of
the
free
flow
of
air
needed
to
ventilate
the
amplifier
and
dissipate
its
heat.
If
the
protection
relay
interrupts
the
sound
even
when
the
amplifier
is
cool,
return
the
amplifier
to
your
NAD
dealer
for
service.
The
protection
circuit
may
be
responding
to
protect
the
speakers
from
an
internal
fault,
such
as
an
improper
DC
voltage
at
the
speaker
terminals.
5.
OVERLOAD
INDICATOR
This
is
an
“audible
clipping”
indicator.
It
flashes
on
when
the
amplifier
is
over-driven
into
audible
distortion.
An
input/output
comparator
continually
compares
the
ampli-
fier’s
output
signal
in
each
channel
with
the
corresponding
input
waveform;
any
difference
that
lasts
long
enough
to
be
audible
(longer
than
a
few
thousandths
of
a
second)
triggers
the
LED
on.
If
this
indicator
illuminates
frequently,
you
should
reduce
your
volume
levels
slightly
(or
purchase
a
second
Model
2600
and
use
both
amplifiers
in
the
bridged
mode
for
greater
power).
NAD
ELECTRONICS
BOSTON/LONDON
©1900
BY
NAD
41
PRINTED
ON
JAPAN
OM-674A
8703
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