funer
input connector
to
the
appropriate
input jack
on
the
preamplifier
andwith the
tunerset inbetween stotions
and the tuner
volume control set
at minimum, find
the
prong position
of the tuner
line cord in one
of the con-
venience receptacles
on the
basic power
amplifiers that
gives the
least hum.
Finally, connect the
phono Input
connectors
to the
PHONO
CH.
1
and CH. 2 Inputs (stereo
mag. cartridge),
or through the
recommended odaptors
to
these inputs (stereo ceramic cortridge),
or to one set of
auxiliary
A
or
B
inputs
(stereo crystal cartridge)
and do
the some with the power
plug of
the
turntable (turntable
off and pickup
arm at rest position)
using the
117VAC
convenience
receptacle
on
the
preamplifier.
When
all
of this Is completed,
adjust the hum balance control
on
top of the
preamplifier chassis for
least hum.
operation
PRELIMINARY:
Be
sure
all
tubes arefirmlyseotedin
their
sockets and that the tubeshlelds
are making good contact
with their
bases. As initial adjustments, set these controls
as follows: LEVEL controls 1 & 2 at
0,
BASS controls
1 &
2 at
0,
TREBLE controls 1
&
2 at
0,
LOUDNESS compen-
sation switch at
OFF.
Turn the
system on by setting the
POWERswitchatON.
Please note that in the irutnjctions
that follow,
it is assumed that o stereo
pickup and/or a
stereo
tape head is being employed
in
the
system.
LEVEL, BASS,
&
TREBLE
controls: The LEVEL, BASS, ond
TREBLE
controls each consist of two concentrically
mount-
ed
controls, one
In
each
channel. A built-in clutching
device is effective
when
the
smaller diameter inner knob
(Amplifier
2 control) Is pressed in against the larger di-
ometerouterknob (Amplifier
1
control). At
the
in(clutched)
position, turning either knobwill
cause both knobs
to turn
together, to
moke
the
some odjustments in both chonnels
simultaneously.
The clutching device is disengoged when
the smaller Inner knob Is pulled out, making it possible to
turn and adjust eachof the controls Independently.
Pleose
note that the
clutching
mechanism
Is designed to
permit
slipping, so thot either
the Inner or outer control con al-
ways
be
turned to either
minimum
or maximum even If
the
other control is engoged to It In
a
more odvanced position
In the desired direction of turning.
The
optional clutching
arrangement
just described In intended to be used in the
following
manner: to adjust level balance, bass balance,
and treble balance between the two chonnels(to accomo-
date the Inevitable gain differences between channels due
to tolerances and aging of components, loudspeaker re-
sponse differences, room acoustics),
the
controls
ore dis-
engaged for independent adjustment;
once bolonce has
been achieved,
the
controls
are engaged to permit sim-
ultaneous adjustments of level, bass and
treble
in both
channels for different records, program material, cmd de-
sires os to listening level.
SELECTOR Switch: The
SELECTOR switch selects corre-
sponding pairs of Inputs
to both channels. The progron
source being fed to
any of these poirs of inputs may be
either stereophonic
or monophonic. The M^OE switch
takes
care
of
setting up the preamplifier according to the
type of the program source (stereophonic or monophonic^
tuner or phono, etc.) and also' performs other functims
detailed In the description of
the MODE switch. The
AUX A, AUX
B,
AM-FM and FM-MULTI ore all high
level pairs of
Inputs suitable for stereophonic or
mono-
phonic crystal cartridges, AMor FM toners,
AM-FM stereo,
FM-FM Multiplex stereo, pre-omplified
equalized tope
ployback, tv
sound, etc. As to monophonic tuner, use
the
AM-FM position for AM tuner selection, and FM-
MULT! for FM tuner selection.
When
Independent
AM
and FM tuners are used, and/or
an FM Multiplex adaptor
is used in conjunction with
or is incorporated in the FM
tuner,
the
some two positions can be used for AM-FM or
FM-FM Multiplex stereo broadcast selection. The
MIC,
PHONO, and TAPE positions
of
the SELECTOR
switch an
all low level pairs of Inputs; the MIC
pair
provide straight
amplification for microphones, the PHONO pair
RiAA
standard equalization and ompllfleatlensuitable for mag-
netic cortridges
or
ceramic
cartridges with appropriate
adaptors,
the TAPE pair NARTB tope equalization
and
ampllficotion for tope heads.
TAPE Switch: Adjusts
the equalization ot theTAPE (head)
position of the
SELECTORswlteh according to the
NARTB
stondord for
the 7
1/2
(&
)
5)
ips tope speeds and the
3
3/4
ips tape speed.
MODE Switch:
The STEREO NORMAL and STEREO RE-
VERSE
positions ore both used for stereophonic reproduc-
tion.
At the STEREO REVERSE position, the
channel 1
and channel 2 amplifien from the
tone
controls to
the
amplifier connections are
Interchanged. These two posi
tions permit Interchanging
thesignaisfed to the twospeakei
so that the correct left
to right display of the orchestra
can be
achieved on all recordings or broadcasts. The
CHECK AMPL. I and CHECK AMPL.
2
positions permit
hearing either channel 1 alone or
channel
2
alone
for
comparison or balancing purposes during
stereophonic use.
The
MONOPHONIC TUNER, AUX position is used for
monophonic
FM, AM,
tv
sound, monophonic phono cort-
ridg^rrtonophonicpre-amplifiedtape
etc.,
fed
Into chan-
nel 1 inputs. At this position,
the
channel
2
Inputs
which
are
unused In this type of operation, ore disconnected
from the
active channel so that they cannot contribute
Interference. At the MONOPHONIC
PHONO
position,
the channel 1 and
2
corresponding inputs are mixed,
which
is useful when
playing rmnophonic records with o stereo-
phonic cartridge to
cancel vertical rumble components.
The Internal
arrangements of the HF-85 at each of the
positions of
the MODE switch are shown in Fig. 2.
6
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