Am Tuner; Selector Switch; Tape Signals; Monitor (Tape/Source) Switch - Marantz 2210 Instructions Manual

"pop" noise for smooth tune in and tune out.
AM TUNER
The AM tuner portion of the Model 2270 has been
provided with a tuned R F amplifier incorporating
a three-section variable capacitor for improved
selectivity and spurious response.
The ceramic filters utilized in the AM IF amp lifier
have very high selectivity and adequate bandwidth
for interference-free AM reception.
Following the AM IF amplifier, the AM detector re­
covers the audio modulation and provides this sig­
na l to the selector switch.
The AM tuner and IF amplifier are subjected to the
action of an effective automatic volume control cir­
cuit which maintains constant the level of all sta­
tions in the AM band.
SELECTOR SWITCH
Your Model 2270 has the capability to operate
from a variety of program sources, e.g., AM or
FM broadcasts, turntable (PHONO), tape recorders
or any other source capable of providing 100
millivolts output level (AUX). The selector switch
connects the inputs of the TONE amplifiers
selectively to the desired source.
TAPE SIGNALS
With the exception of tape input, all high-leve l
inputs are fed directly to the selector switch. Tape
input is routed through the MONITOR (1, 2)push ­
switch and front panel dubbing IN jack to a
section of the MONITOR (TAPE/SOURCE) switch.
The dubbing IN jack is a three-conductor stereo
jack which has two built-in switches, one for each
channel. Normally, these switches are closed,
allowing the tape input signals from the PLAY
(1 and 2) jacks on the rear panel to be fed to the
MONITOR (TAPE/SOURCE) switch. When a plug
is inserted in the dubbing IN jack, the switches
are opened, disconnecting the PLAY (1 and 2)
jacks and allowing the signal from the dubbing
IN jack to reach the MONITOR (TAPE/SOURCE)
switch. Thus only one tape recorder at a time can
feed playback signals into the Model 2270.
MONITOR (TAPE/SOURCE) SWITCH
When the MONITOR (TAPE/SOURCE) pushswitch
is in the "out" position tape input signals from the
PLAY (1 and 2) jacks on the rear panel or
dubbing IN jack on the front panel are fed to
the selector switch. When the MONITOR (TAPE/
SOURCE) is depressed, the output of the selector
switch is disconnected from the balance control
and the tape input signals from the TAPE IN
or dubbing IN jacks feed the balance control
directly.
MONITOR (1 and 2) SWITCH
This switch selects between the tape PLAY 1 or 2
jacks on the rear panel. Depressing the switch se­
lects input signal connected to the PLAY 1 jacks
and releasing the sw itch (out position) PLAY 2 ja­
cks.
PHONO SIGNALS
Phono signals of up to 100 mil livolts can be handled
without overloading. The R fAA equalization
network provides precise equalization and sets
the voltage gain of the phono preamplifier to
40dB (at 1,OOOHzl. This RIAA reproducing charac­
teristic, together with the recording characteristic,
is shown in Figure 9. Notice that the net result
after playback is a flat response.
Hi BLEND AND MONO (L and R) FUNCTIONS
When the Hi BLEND switch is depressed the left
and right channel outputs of the selector switch
are connected together through mixing resistors and
a capacitor. The value of the capacitor has been
selected to effect moderate suppression of out-of ­
phase noise and d istortion components while main ­
taining moderate stereo separation. When both MO­
NO (L and R) switches are in the "in" position, the
two channels are connected directly together th­
rough mixing resistors. In addition, the left and
right channel tape input signals are connected to­
gether through a similar resistor network. This faci­
lity allows all inputs to be converted to the mono­
phonic mode.
CONTROL CIRCUITS
The control circuits portion of the Model 2270
consists of the balance, volume, bass, mid, treble,
Hi FILTER, and LOW FILTER controls. All con ­
trois affect the left and right channels simultane­
ously. The bass, mid and treble controls have
clutched sections which allow individual adjust­
ment of tonal balance for each channel. With
the controls set for flat response and volume con ­
trol at maximum, the over-all voltage gain from
any high-level input to the loudspeaker termi­
nals is approximately 43dB.
BALANCE CONTROL
The balance control is a wide-range control which
perm its attenuation of each channel to cutoff. The
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