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. 1and CH. 2Inputs (stereo
mag. cartridge), or through the recommended odaptors to
these inputs (stereo ceramic cortridge), or to one set of
auxiliary Aor Binputs (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&2at 0, BASS controls 1&
2at 0, TREBLE controls 1&2at 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 ostereo 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. Abuilt-in clutching
device is effective when the smaller diameter inner knob
(Amplifier 2control) Is pressed in against the larger di-
ometerouterknob (Amplifier 1control). 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 amore 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-FMstereo,
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 71/2 (& )5) ips tope speeds and the 33/4
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 2amplifien 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. Iand CHECK AMPL. 2positions permit
hearing either channel 1alone or channel 2alone 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 1inputs. At this position, the channel 2Inputs 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 1and 2corresponding inputs are mixed, which
is useful when playing rmnophonic records with ostereo-
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
