Eico ST 40 - Output Connections; Speaker Connections; Speaker Terminal and Phasing

EyggD
st«o
OUTPUT
CONNECTIONS
TAPE
RECORDER
The
TAPE
OUT
l
&
TAPE
OUT
2
iacks
are
Intended
for
feeding
signals
out
to
the
"line"
recording
inputs
of
a
tape
recorder.
These
are
Independent
outpi
s for
channel
1
and
channel
2,
respectively.
They
are un-
affected
by
the
LEVEL,
BALANCE,
BASS,
TREBLE,
HI
FILTER,
and
LO
FILTER
controls.
SPEAKER
CONNECTIONS
WARNING:
Do
notoperatetheamplifierwithout
first
connecting
speakers
to
the
speaker
connection
termi-
nals,
exactly
as
described
below.
Every
speaker
has a
rated
impedance,
which
may
be
16, 8,
or 4
ohms.
For
an
amplifier
to
provide
rated
power
output
with
rated
distortion,
the
speaker
used
with
it must
be
connected
to
the
output
transformer
tap
corresponding
to
its
impedance.
On
the
rear
apron
of the
unit,
there
are
three
4-con-
nection
Terminal
Boards
(TB).
Silk-screened
on
the
apron
is
a
diagram
for
connecting
upto
three
speakers;
one
each
for
channels
land
2,
and
an.
optional
center
channel
speaker.
To
agree
with
the
established
conventions
of
stereo,
connect
the
left
speaker
to
the
channel
1
output,
and
the
right
speaker
to
the
Channel
2output,
after
read-
ing
the
connection
information
below.
The
boardat
the
left, TB1,
carries
the
impedance
taps
for
channel
1.
The
board
at the
lower
right, TB3,
carries
the
impedance
taps
for
channel
2.
SPEAKER
TERMINALS
FIG.
I
PAGE
5
The
left
board,
TB1,
carrying
the
channel
1
impedance
taos
(16,
8,4£)1.
also
includes
the
common
terminal
('..<
for
channel
1.
The
channel
1
speaker
is
connected
to
this
common
terminal C
and
the
appropriate
channel
1 imp,
dan
se
tap,
as shown.
The
lower
right
board, TB3,
carrying
the
channel
2
impedancetaps(16,8,4Q),
does
not
carry
the
common
-
terminal
C
for
channel
2,
in
fact,
the
channel
2
speaker
Is
npt
to
be
directly
connected
to this
board
atall.
The
upper
right
board,
TB2,
provides
the
con-
nection
terminals
for
the
channel
2
speaker.
As
the
diagram
shows,
the
channel
2speaker
is
to be
connect-
ed
between
the
right-hand
pair
of
terminals
on
board
TB2.
Note
that
the
terminal
at
the
extreme
right
Is
marked “C",
thisbeingthe
common
terminal
for
chan-
nel 2.
To
complete
the
connection
of
the
channel
2speaker,
T
jumper
wire
must
be
connected
between
the
third
terminal
from
the
right
on
the
upper
right
board,
TB2,
and
the
appropriate
impedance
tap
on
the
lower
rigm
board, TB3,
as
shown
in
the
diagra
rru
There is
a
third
speaker
shown
in
the
diagram,
labelled
CENTER
5PKR.
(OPTIONAL).
Aresistance
symbol
is
shown
inserieswith
this
speaker,
as
well.
This
resist-
ance
symbol
stands
for
an
attenuator
to
reduce th-
•
vel
of the
center
speaker
appreciably
below
that of
the
channel
land
2speakers
so
asto
produce
"eenterfill"
without
markedly
diminishing
the
stereo
effect.
For
this
purpose
we
recommend
an
adjustable
50
ohm,
25
watt
wi re
-wound
dropping
resistor
suchastKe
Obmite
''Dividohm
1
','
mounted
on the
rear
panel of
the
center
chameT
speaker
adjacent
to
the
speaker
terminals.
Connect
the
sliding
divider
on
the
resistor
to
one
of
the
speakerterminals,
allowing
enough
slack to
permit
the
slider
to
be
moved
along
the
body
of
the
resistor.
Now
connect
the
other
speakerterminal
to
the
extreme
left-
hand
terminal
on
the
upper
right
board,
TB2,
on
the
amplifier,
and
then
connect
one
end
terminal
of
the.
dividing
resistortothe
same
impedance
tap on
the
left
board,
TB1,
used
for
the
channel
1
speaker.
These
connections
are
shown in
the
diagram*
The
speaker
connection
diagram
si
Ik-screened
on
to the
rear apron
of
the
amplifier
is
reproduced
in
Fig.
k
with
additional
polarity
Indications
which
will
assist in
phasing
the
speakers
properly
if
your
speakers
are
mark-
ed
as to
polarity*
A physical
representation
of
the
speaker
connections
Is
glvOTi
inFIg.
2* if
your
speakers
are not
marked
as to
polarity,
use
the
phasing
method
given
below.