HITACHI
SR-2004
--.-----
FEATURES
Tuner
Section
-------------------
1.
Dual Gate MOS FET for High Quality
FM
Tuner
Three Dual Gate MOS
FET's
in
the
front-end
and
5-gang
variable capacitors offer excellent
FM
sensitivity
(I.5j1V), intermodulation characteristics, high S!N ratio
and
spurious rejection.
2.
Auto-Lock
Circuit
To
stabilize tuning, an
Auto-Lock
circuit
is
provided.
This circuit engages immediately when
you
release the
tuning
knob
after precise tuning.
Just
by
touching the
tuning
knob,
you can disengage
the
Auto-Lock circuit
for
(the
Auto-Lock indicator goes
off)
fine tuning.
Releasing
the
tuning knob re-engages
the
Auto
Lock
circuit which automatically stabilizes the tuning circuit
and
locks
onto
the station selected for a high S!N ratio
and
low distortion.
3.
IF
BAN
D Selector Switch for Flexible Selectivity and
SAW
FI
LTER for Low Distortion
IF
BAND selector switch
is
provided in the
FM
IF stage
to
provide a selectivity
that
meets different receiving
conditions.
In the WIDE position,
the
SAW
FILTER,
which has
superior group delay characteristics in the wide fre-
quency range, and
the
4-pole
LC
LINEAR PHASE
FILTER
offer sound with
extra
low distortion.
In the NARROW position,
the
2 LINEAR PHASE
CERAMIC
FILTER
will also
operate
to
cut
out
the
interference sharply by high selectivity.
4.
High-Selectivity and Low-Distortion IF Amplifier using
IC's
and
3 Ceramic Filters
A 6-stage differential amplifier
is
employed.
The exten-
sive use
of
3
Ie's,
and
two
ceramic filter elements in the
IF stage,
that
have good phase characteristics, in the
FM-
IF amplifier greatly improves
the
limiter and selectivity
characteristics.
5.
Quadrature
Detection
Quadrature detection
with
the
extensive use
of
Ie's
has
a wide
band
coverage and low
distortion.
6.
Phase-Locked Loop
IC
for
FM/MPX Circuit
A PLL-IC, which was developed
by
Hitachi,
is
used for
the
FM!MPX circuit for a high separation
and
low dis-
tortion.
Also, high reliability
is
achieved with respect to
temperature
and aging.
7.
Reed Relays for Cutting
out
Detuning Noise
In the
FM
MUTE position,
two
Reed Relays are pro-
vided in
FM
audio
output
stage
to
cut
out
detuning
noise.
8.
MPX NOISE FILTER
Sometimes
high frequency noise prevents
you
from
obtaining
hi-fidelity
FM
stereo reception. With some
receivers,
you
have
to
listen
to
broadcasts
in
mono
to
reduce this noise.
The
MPX NOISE
FILTER
can be used
to
reduce this
noise
without
imparing
the
FM
stereo effect.
9.
FM
MULTIPATH Switch with Meter
for
Best
FM
Reception
Direct signals and signals reflected by mountains and
buildings cause a multipath effect. This increases dis-
tortion
and downgrades separation.
To
eliminate this trouble, there
is
a
multipath
detection
circuit which operates together with
the
signal meter.
10.
3-gang Variable Capacitor for High Selectivity
AM
Reception
A 3-gang variable capacitor
is
provided for achieving high
sensitivity and selectivity during
AM
reception.
11. Ceramic Filter,
ICs
in
AM
Tuner
A ceramic filter
is
employed in
the
AM
tuner
to
obtain
enhanced
selectivity and AGC characteristics. The exten-
sive use
of
Ie's
improves stable reception.
12.
Two
Large Easy-to-Read Meters
and
a Large-sized Fly-
wheel Tuning Knob
Two
easy-to-read meters are used
to
indicate the signal
and
tuning
levels.
The dial mechanism employs a large-sized fly-wheel with
a high
moment
of
inertia for easy operation.
Audio
Section
------------------
1. Newly Developed High-Efficiency High-Power
Audio
Amplifier (Series E ..... Class G
or
Dynaharmony
Amplifier)
This amplifier delivers a higher
dynamic
oUlpuCpower
(400
W per channel, 8 ohms)
without
distortion than
conventional class-B amplifiers.
The
relative low power
consumption
of
class G opera-
tion minimizes the
heal
sink
of
the
power transistors and
the weight
and
size
of
the whole amplifier.
This amplifier has twin
DC
power supplies.
Under this
method,
c1ass-G
operation
can deliver dy-
namic power which
is
more
than
twice the value
of
the
maximum
rated
output
power
or
more.
2. Twin Power Meters
(L
and R channels)
To
see
the
actual power
output
while
you
are listening,
combined
two new attractive
power
meters are provided.
3.
Midrange
Tone
Control
This amplifier has
not
only BASS
and
TREBLE tone
controls
but
also a MIDRANGE
tone
control.
By
setting these three controls,
you
can choose
the
pre-
ferred frequency characteristics
of
the
amplifier.
The
controls all have
11
click-stop
contact
points.
This feature offers good feel which makes for easier set-
ting
and
resetting.
4.
Turnover
and Tone Defeat Switches
This model has
two
turnover switches for adjusting the
low
and
high frequency characteristics independently.
Each switch has two turnover frequency settings.
In
order
to
make flat frequency characteristics
without
touching
tone
controls
tone
defeat functions are also
provided. You can adjust the frequency characteristics
to
meet
the acoustic conditions
of
you
listening room
and
to
suit
your
taste.
5.
Calibrated
Attenuator
(Volume Control)
A precisely calibrated 32- click-stop
contact
point
atten-
uator
is
used for the volume
control.
This makes for
easier setting and resetting
of
the
desired power
output
level.
6.
Audio
Muting Switch
This switch
is
very useful when lowering
the
sound level
without
touching the level
attenuator.
You can choose
between
two
attenuation values
(-20dB,
-40dB).
Further,
a more precise and flexible setting
and
resetting
of
output
level can be achieved
by
combining the level
attenuator
and the muting switch.
7. Mic Mixing
A mic mixing circuit
is
incorporated
in this model.
Just
connect
a microphone and
you
will be able
to
mix
sounds from the microphone
with
other
program
sources.
e
e
•
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