Technics RS-B765 - Page 7

Mi CONNECTIONS
LINE IN
E
RS-B755
AC IN SOCKET
(Connect the AC power supply cord.)
LINE OUT terminals (Connect the stereo connection cable.)
LINE !N terminals (Connect the stereo connection cable.)
Mi
RECORDING
WITH
HIGH
TONE
QUALITY
MPxX filter
Because the pilot signals’, etc. included with FM stereo broadcast
signals are subjected to Dolby noise-reduction processing in the
same way as the music signals when an FM stereo broadcast is
being recorded, there is apt to be deterioration of the tone quality,
and the noise-reduction effect is reduced.
This unit, however, is provided with an MPX filter that filters out the
19 kHz frequency, which is the frequency of the pilot signal.
Note that there is virtually no audible effect upon the tone quality as
a result of the use of the MPxX filter.
Multiplex filter switch
This switch can be used during the recording of an FM stereo
broadcast that employs Dolby noise reduction so as to
prevent misoperation of the Dolby noise reduction.
This switch, however, should be switched OFF when a sound
source other than the FM broadcast is being recorded, such
as, for example, a sound source that has a wide frequency
range, such as a compact disc, etc.
“Pilot signal
The pilot signal is a signal that is used to separate FM broadcast
signals in stereo (left and right channels); this signal is generated
on a frequency that is very close to the 19 kHz music band.
—5—
The recording-equalizer amplifier is an amplifier for supplying (to
the head) the current necessary for recording. Usually, loads such
as the recording head and bias trap circuitry (circuitry for control of
the bias current) would be applied to the output of this amplifier,
with the result that complex changes of the current phase occur,
causing distortion of the recording signal.
The recording-equalizer amplifier used in this unit, however, is a
linear magne-field class AA amplifier that is a combination of
class A voltage-contro! amplifier circuitry and current-drive ampli-
fier circuitry. (See the figure below.) As a result, a current flow that
is equivalent to the current flowing in the pure resistance of the
current-drive amplifier can be supplied to the recording head.
Consequently, a magnetic field that corresponds to the input
signals is produced at the head and is recorded on the tape, which
means that recorded sounds are faithful to the original sound
source, without fluctuations of the current phase.
CLASS A VOLTAGE CURRENT DRIVE AMP
CONTROL
AMP
(V-|
CONV.)
@ Pure resistance
@ Current flowing through the current-drive amplifier’s pure
resistance and current flowing through the recording
head become equivalent.