However, theHF-89 outlets may be used also, if desired,
in which case both of them will be "switched".
INTERCONNECTION OF COMPONENTS: SIGNAL
All input connections are to be made using single conduc-
tor shielded cable. Unless the source has alow impedance
output, such as acathode follower (withwhich up to 50 ft.
of cable can be used), use the shortest possible connec-
tion. In any case, use alow capacity type of shielded
cable (as low as 25mmf capacity per foot is available).
Both ends of the cable must be fitted with RCAtype phono
plug connectors. For speaker connections, use plastic
covered lamp cord or flat ribbon twin lead.
(la, lb, lc below are possible input connections)
la) STEREO CONTROL PREAMPLIFIER TO HF-89 DUAL
POWER AMPLIFIER: Use two cables as described above.
Connect one cable from preamplifier output 1to input 1
on the HF-89. Connect another from preamplifier output
2to input 2on the HF-89. Set the Service Sel switch
at the SEPARATE position. Power amplifier can deliver
50watts per channel. DO NOTuse dual conductorshield-
ed lead.
lb) MONAURAL CONTROL PREAMP TO HF-89 DUAL
POWER AMPLIFIER: Use one cable as described above.
Connect this cable from the preamplifier output to input
2on the HF-89. Put the Service Sel switch into the
COMBINED position. The power amplifiers can deliver
atotal of 100 watts to the speaker.
lc) USING YOUR OLD AMPLIFIER: You can use your
old power amplifier or integrated amplifier for one stereo
channel, and the HF-89 connected for parallel operation
of the dual amplifiers for the secondstereo channel. This
may be worthwhile only if your old amplifier has a rated
power output of at least 50 watts. Connect one cable
from stereo preamp output 1to input 2of the HF-89 and
set the Service Sel switch at the COMBINED position.
With the speaker connection terminals of the dual ampli-
fiers connected in parallel, the HF-89 can deliver 100
watts to the speaker in stereo channel 1. Connect another
cable from stereo preamp output 2to input of your old
power amplifier or to the tuner or auxiliary input of your
old integrated amplifier. (In the latter case, set the tone
controls of the old amplifier to "flat" and loudness contour
or filter controls to no effect). The power capability of
the second channel will then be the same as that of your
old amplifier.
(2a, 2b, 2c, 2d below are possible output connections)
2a) In the situation described in la above, for stereo
operation connect one speaker system between "G" and
the appropriate impedance tap on the speaker connection
terminal board for amplifier 1. Similarly, connect the
appropriate impedance tap on the speaker connection board
for amplifier 2. If you have only one speaker system at
this time, and wish to use the power of both amplifiers
combined to drive it, then use the parallel operation
connection described in 2d below.
2b) In the situation described in lb above, if you have
two speaker systems connect one to each speaker connec-
tion terminal board (one for each amplifier) just as de-
scribedin 2a above. If you have only one speaker system,
use the parallel operation connection described in 2d
below.
2c) In the situation described in lc above, it is implied
that you have two speaker systems. Connect one speaker
system to your old amplifier and the second speaker system
to theHF-89 dual power amplifiers connected in parallel
as described in 2d below.
2d) Parallel operation of theHF-89 dual power amplifiers
with full 100 watts output is possible for speaker upto 8
ohms impedance: First determine the rated impedance of
the speaker system to be connected to the paralleled am-
plifiers and multiply it by two. Locate the connection
terminals on each of the two speaker connection terminal
boards on the HF-89 assigned to the tap of this value.
Connect an external jumper wire between this particular
pair of terminals (16 to 16 for an 8Clspeaker, or8to 3for
a40speaker). Finally, connect the speaker between one
of the "G" terminals and one of the pair of terminals
connected together by the jumper wire.
CONTROL ADJUSTMENTS
a) TheINPUT LEVEL ADJ. controls are intended to pro-
tect the speaker system from "blasting" should someone
turn the preamplifier-control unit level controls to full.
It permits you to attenuate the preamplifier output signal
by the desired amount at the input to the power amplifier
where it can not be "fiddled" with. Start by setting the
INPUT LEVEL control to the maximum counter-clockwise
(maximum attenuation) position using ascrewdriver. Set
the LEVEL control on one channel of the preamplifier at
the midpoint of its range of rotation. Turn your phono-
graph on and play an average orchestral record. Then
slowly rotate the appropriate INPUT LEVEL ADJ. control
clockwise until the music isatnormal (or concert) listen-
ing level. Repeat for the second channel. This completes
the adjustment.
b) ON-OFF SWITCH: Should be set at the ON position
when the unit is used with apreamplifier. It may be used
as apower on-off switch when the amplifier is accessible.
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