Harman kardon a 400 owners manual

Page 2

OUTPUT

Two receptacles, marked Output will be found
at the rear of the chassis. For your convenience in
connecting to the amplifier, a 36 shielded cable
will be found in the Counterpoint package. Plug
one end of this cable into either one of the two out-
put receptacles, and the other end into the appropriate
amplifier input receptacle.

Since the output circuit of the Counterpoint in-
Cludes a Cathode-follower, this cable may be extend-
ed to any reasonable length without deterioration of
tone quality.

The second output receptacle may be similarly
connected to a tape recorder, to provide program mat-
erial unaffected by the tone and volume controls of
the amplifier.

The output level of the Counterpoint may be
adjusted to suit the input requirements of the ampli-
fier, or tobalance with the volume of another program
source (such as a record player), by means of the
control marked "Output Level".

VENTILATION:

All electrical equipment generates heat, which
must be allowed to escape. Although the Counterpoint
is well ventilated in itself, sufficient space should be
allowed around it to permit free air flow. If it is
placed in a bookcase, it should be locatcdwell toward
the front, to provide as much clearance as possible
at the rear.

Do not put books or other objects on top of the
Counterpoint. Covering the perforated tube grill will
reduce the ventilation and result in sharply reduced
component and tube life.

OPERATION:

CONTROLS

The Harman-Kardon Counterpoint has only 2 front
panel operating controls. The Tuning Knob (at the
right) is used to tune to the desired station. The
Power-AFC control (at the left) serves to turn the
power off in its extreme counter-clockwise position.
A small amount of rotation from this position will turn
the power on, with a click, and further rotation serves
to adjust the degree of Automatic Frequency Control
up to a maximum at the extreme clockwise position.

TUNING METER

The precise HARMAN-KARDON tuning meter oper-
, ates whether AFC is in circuit or not. When the
Counterpoint is tuned completely off any station, the
tuning meter will point to zero. As you tune through
a station, the needie will swing to one side, then to
zero, then to the other side, and as you tune away
from the station, back to zero. The tuning is proper
only when the needle points to approximately zero.

AUTOMATIC FREQUENCY CONTROL (AFC)

FM Broadcasting, by its very nature, eliminates
almost all natural and man-made static. However,
the characteristics of FM which make this possible
also make for problems in tuning. The HARMAN-
KARDON Counterpoint incorporates an effective
Automatic Frequency Control (AFC) circuit that over-
comes these problems and insures proper tuning even
if the manual tuning is not accurately done. The fol-
lowing experiment will lead to an understanding of
AFC, and the fuller enjoyment of the Counterpoint.
First, rotate the Power-AFC'control to the extreme
clockwise position. Now tune across the scale. Note
how the stations pop into place, one after the
other. Now tune to any station, preferably one with
a musical program. Turn the "Power-AFC control
counterclockwise as far as possible Without turning
the set off. This defeats the AFC. Tune slowly
through the station from left to right. Notice that
there are three points where the station sounds clean,
interspersed with points of distorted sound. The
middle clean-sounding point is the proper tuning
position for the best tone quality with minimum noise
and interference. At this point the tuning meter will
indicate proper tuning. Tune slightly away from the
proper tuning position, until the sound is distorted.
Note that the tuning meter will indicate improper
tuning. Now reactivate the AFC by turning the
"Power-AFC knob to the right. You will. notice
that the Sound cleans up and the proper tuning in-
dication is restored, as if the receiver had been man-
ually returned.

Actually, the tuning has been electrically read-
justed by the operation of the AFC circuit, which
automatically retunes the electronic circuits to the
center of the station channel.

The AFC circuit of the Harman-Kardon Counter-
point performs the further function of overcoming any
tendency of the tuner to drift.

In order to take maximum advantage ofthe benefits
of AFC, it is suggested that tuning be done with AFC
off, to render the indication of the tuning meter more
precise. When AFC is then turned on, the tuning will
be improved by a ratio of 10 to 1.

This procedure is especially recommended in those
areas where a weak station is found close to a strong
station. Under this condition, the AFC may tend to
reach for the strong station and completely skip over
the weak one. If the weak station is tuned in without
AFC, it will be locked in when the AFC is turned on.

Another procedure might be to find that setting of
the AFC control which provides the exac: amount of
A F C action for most convenient tuning in your
location.

To do this, tune to a portion of the dial where
a strong station is found immediately adjacent to a
weak station. (If this situation cannot be found in
your location, leave the AFC control at maximum).