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HITACHI SR-2004
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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 differen t 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 de tuning
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.
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