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fence
outlet
in
the control unit.
Note:
When
using a
self-powered
preamplifier-control
unit,
touch
one end
of
a
wire
to
the preamplifier chassis
and
the other
end
to
the
power
amplifier
chassis.
If
a spark occurs,
pull
out the
HF-35
line
cord plug
and
re-insert
it
with
the prongs re-
versed,
c)
POWERING
AUXILIARY
PREAMPLIFIER:
The same
octal
socket prav
ides a
1
1
n
ec
essary
f
i I
am
en
t
and
B+
vo
I
tages
for
operating an
auxiliary preamplifier-control
unit,
6,3
volts
AC
filament voltage,
at
1
ampere,
may
be obtained
from
pins
1
and
2;
pin
number
4
on
the socket supplies
350
volts
DC
,
at a
maximum
current
of
10
nnllliamperes;
and
pin 3
is
connected
to
ground. As
stated
above, con-
trol
of
117
volt
AC
line
power
to
the
power
amplifier,
and,
indirectly,
power
for
the preamplifier-control unit
Itself,
Is
made
available through
the
connections
to
pins
6
and
7,
This
arrangement
Is
exactly
suitable for
power-
ing the
EiCO HF-65A
and
HF61A
preampl
if
ier-contro
I
unit;
all
that
need be done
Is
to
remove
the octal plug
provided with
the
HF-35
from
the octal socket
and
Insert
the octal
plug
-and
- cable
of the
HF-65A
in
its
stead*
Note
that
a jumper between
pins
2 and
3
of the octal
plug furnished with the
HF-35
effectively grounds
one
side of
the
filament
winding; removal
of the octal
plug
leaves the filament
winding
Floating.
This
arrangement
bused becausea hum
balance
control
is
connected
across
the
filament leads
In
the
EICO HF-65A
preamplifier
and
the
arm
of
this
control
is
returned
to
ground*
d)
CONVENIENCE
OUTLETS:
When
the
HF-35
is
used
with a preamplifier that takes
power
from
tt,
such
as the
EICO
HF-65A,the convenience
outlets of the
HF-35
will
be
foundusefuL
The
outlet
marked
11
1
17VAC
SW."
("SW.
M
Is
an
abbreviation
for
"
SWITCH
ED")
is
"five
1
*
or
"dead
11
depending on whether
the
preamplifier
power
switch turn-
ed
to
ON
or
OFF;
plug
tuners into
this
outlet.
The
outlet
marked
11
1
17VAC
1
*
is
not
switched
and
is
"live"
whenever
the
HF-35
line
cord plug
is
Inserted
in
a
wa
1
1
outlet;
plug
a record
changer
Into
this
outlet
in
order
to
protect the
mechanism*
When
the
HF-35
Is
used with a
self-powered
preampl
ifier,
such
as
the
EICO
HF-65A,
normal
ly
the
con-
venience
outlets
on
the preamplifier
will
be
used*
How-
ever, the
HF-35
outlets
may
be used
also,
if
desired,
in
which
case both of
them
will
be "switched
INTERCONNECTION OF
COMPONENTS
SIGNAL
a)
PREAMPLIFIER
-CONTROL
TO POWER
AMPLIFIER:
Single conductor, shielded
cable must be used
to
inter-
connect
the preamplifier-control unit or
tuner-preampli-
fier- control unit
and
the
power
amplifier*
Unless
the
source has a low
Impedance
output, such
as
a
cathode
fol-
lower
(with
which up
to
50ft.
of
cable can be
used), use
the shortest possible
connection;
In
any
case,
use a
low
capacity
type
of
shielded
cable
(as
low
as
25
mmf
capacity
per
foot
b
available).
Both
ends
of the
cable must be
fitted
with
RCA
type
phono
plug connectors.
b)
SPEAKER
CONNECTIONS:
To
connect
your speaker
to
the amplifier properly,
you
must
know
Its
rated
Imped-
ance,
which
is
usually
marked on
the
speaker
or specified
in
the manufacturer's
literature.
Connect one
speaker
lead
to
the terminal
on
the
rear
apron
marked
"
G"
and
the
other speaker lead
to
the
nearby
terminal designated
by
the rated
speaker
impedance
(4,8,
or
16 ohms).
Plastic-
covered lamp
cord
may
be
used
for
distances
up
to
50ft.
with
little
power
loss*
For shorter distances,
tv
antenna
lead
can be
used, particularly
if
it
Is
desired
to run
the
speaker
lead
under
a
rug.
If It
is
desired
to
use
two
similar or identical full-range
speakers
of
the
same
rated
Impedance
(either
8or
16
ohms
only)
for
better
sound
distribution,
connect
one
speaker
lead of
each
pair to
11
G"
and
the
two remaining
leads
to
the terminal
with
a number
equal
to half of
one
of
the
speaker's rated
impedance.
(It
may
be necessary
to
"phase"
the
two
speakers
by
reversing both of the leads from
one
of the speakers,)
This
may
not
be done
if
each
of the
speakers
is
designed
for
reproduction of a
different part
of the
audio
spec
turn
(woofer- tweeter
comb!
notions).
In
which
case a cross-over network
Is
required
which
connects
to
the amplifier
with only
one
pair of leads,
INTERCONNECTION
PROCEDURE
a)
Make
all
system interconnections before applying
AC
power.
Making
or
breaking interconnections while
AC
power
is
applied
will
result
in
a
momentary
overload
of
both
the
power
amplifier
and
speaker system with
possible
damage
to
either
or
both,
b)
If
the
EICO HF-65A
or
HF-61A
preamplifier control
unit (note
self-powered)
has
been
obtained
in kit
form, re-
move
all
the
jumper connections
In
the octal
plug supplied
with
the
HF-35
and
wire
the preamplifier
power
take-off
leads
to this
plug
as
follows:
Color
of
Preamp* Lead
Fin of
Octal
Plug
Connected
ro
grey
6
grey
7
brown
1
brown
2
red
4
black
3
Wired
HF-65A
and
HF-61A
preampl
i
fieri
wilt
have
the
preamplifier
leads
connected
to
the octal
plug
as
in
the
table
above.
c)
If it is
desired
to
use
a
preamplifier
without
a
power
supply other than
the
HF-65A
or
HF-6IA,
the
power
take-
off
leads of the preamplifier
should
be connected
to
the
HF-35
octal
plug
(after
removing
the jumpers) as follows:
4
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Table of Contents
Troubleshooting
