Hitachi SR
2004 with its exclusive Class G amplifier delivers 200 watts per channel RMS
into 8 ohms with only 0,08% THD. But during demanding musical peaks, that
unique amplifier does an amazing thing. It actually doubles its power to 400
watts per channel RMS to prevent any possibility of clipping or distortion.
There is no known speaker system or musical recording that the SR 2004 cannot
handle effortlessly and magnificently.
Its host of
advanced features include FM auto-lock, FM muting, phase lock loop circuitry,
power protection circuit,mic mixing, hi/low filters, dual power meters, detent
control, 3 pairs of speaker connections, switches and indicator lights.
For those
who want the power and performance of the finest separate components in a
compact receiver there is one incomparable answer. The Hitachi SR 2004
Features
Tuner Section
Dual Gate
MOS FET for High Quality FM Tuner
Auto-Lock
Circuit
IF BAN D
Selector Switch for Flexible Selectivity and SAW FI LTER for Low Distortion
High-Selectivity
and Low-Distortion IF Amplifier using IC's and 3 Ceramic Filters
Quadrature
Detection
Phase-Locked
Loop IC for FM/MPX Circuit
Reed Relays
for Cutting out Detuning Noise
MPX NOISE
FILTER
FM MULTIPATH
Switch with Meter for Best FM Reception
3-gang
Variable Capacitor for High Selectivity AM Reception
Ceramic
Filter, ICs in AM Tuner
Two Large
Easy-to-Read Meters and a Large-sized Flywheel Tuning Knob
Audio
Section Features
Newly
Developed High-Efficiency High-Power Audio Amplifier (Series E ..... Class G or
Dynaharmony Amplifier)
Twin Power
Meters (L and R channels)
Midrange
Tone Control
Turnover and
Tone Defeat Switches
Calibrated
Attenuator (Volume Control)
Audio Muting
Switch
Mic Mixing
Tape Dubbing
Low Filter
and High Filter
Three
Speaker Systems Connection
Electronic
Protection Circuit
Adaptor
Switch
DESCRIPTION
OF THE NEW CIRCUIT
SAW filter
FM-IF
section of this model is so designed that 2 types of the frequency band
characteristics (WIDE, NARROW) can be selected.
Namely, when
the IF band switch is set to WIDE, the SAW fIlter and 4-pole linear phase
filter are used to suppress distortion to a minimum to improve the group delay
characteristics. When the IF band switch is set to NARROW, 2 ceramic filters
are used in addition to the above SAW filter and the 4-pole linear phase filter
to improve selectivity characteristics. In addition, amplification is performed
by IF Amp to compensate for losses caused by insertion of the two ceramic
fIlters. Accordingly, positioning at
NARROW is convenient when there is interference from a station close by when
receiving a long distant station.
Dynaharmony
(Class G Amplifier) output circuit
The level of
the music source changes momentarily, the percentage of high level (over 1/2 of
peak value) is very small, it is only less than 2% of the total music signals.
Large output
amplifiers have been used conventionally to playback at high levels without
distortion; however, in this case, high voltage is impressed to the output
transistor, so the power consumption is large.
Studies have
been made, how to obtain high output powers without the increase of the output
transistors' consumption in order to improve the efficiency. Thus, the new
dynaharmony output circuit (Class G Amplifier) was developed.
Current
mirror circuit
This set
contains a current mirror circuit which drives the output stage in push-pull
operation to keep distortion low.
Constant
current circuit
This
constant current circuit stabilizes the bias of the main amplifier circuit.
Idle current
compensation circuit against power supply voltage fluctuations
Protection
circuits
(1) Muting
circuit
(2) ASO
(Area of Safety Operation) detection circuit (output transistor protection)
(3) DC
voltage detection circuit (speaker protection)
Specifications
FM Section
Frequency
Range: 88 - 108 MHZ
Usable
Sensitivity [Mono/Stereo]: 8,7 dBf
(1,5µV) / 24 dBf (8,9µV)
50 dB
Quieting Sensitivity [Mono/Stereo]: 12,5
dBf (2,3 µV) / 36 dBf (34,5 µV)
Signal-to-Noise
Ratio (at 65 dBf)[Mono/Stereo]: 75 dB /
70 dB
Harmonic
Distortion (at 65 dBf)
Narrow
[Mono/Stereo]:
100 Hz
: 0,15% / 0,25%
1 kHz : 0,1% / 0,2%
6 kHz : 0,25% / 0,3%
Wide
[Mono/Stereo]:
100 Hz
: 0,15% / 0,25%
1 kHz : 0,07% / 0,1%
6 kHz : 0,2% / 0,3%
Frequency
Response: 30 Hz - 15 kHz +0,5 -1,0 dB
Image
Response Ratio: 115 dB
Spurious
Response Ratio: 120 dB
IF Response
ratio: 115 dB
Alternate
Channel Selectivity [Narrow/Wide]: 85 dB
/ 45 dB
Capture
ratio: 1 dB
AM
Suppression: 60 dB
Stereo
Separation: 50 dB (1 kHz)
Sub Carrier
Suppression: 70 dB
SCA
Rejection: 70 dB
Muting
Threshold: 28 dBf (14 µV)
Antenna
Input: 300 Ω balanced, 75 Ω unbalanced
AM Section
Frequency
Range: 530 - 1605 kHz
Sensitivity: 370 µV/m (S/N 20 dB), 20 µV (IHF, ext.
Antenna)
Image
rejection: 70 dB
IF
Rejection: 90 dB
Selectivity
(IHF): 40 dB
Signal-to-Noise
Ratio: 50 dB
Antenna: Ferrite and Separate terminal
Audio
Section
Output
RMS Power (both channel driven): 200
watts per channel, min. RMS at 8 Ω
from 20 -20,000 Hz, with no more than 0,08% THD
Music Power
(IHF):
230 W
+ 230 W per channel at 8 Ω, 1 kHz,
THD 0,08%
230 W
+230 W per channel at 4 Ω, 1 kHz, THD
0,1%
400 W + 400
W per channel at 8 ohms
Power
Bandwidth: 10 Hz - 40,000 Hz
Frequency
Characteristics:
Phono : 30
Hz - 15 kHz ±0,2 dB
AUX : 10 Hz - 40 kHz ±1,5 dB
Harmonic
Distortion
Less than
0,08% at rated output
Less
than 0,03% at ½ rated output
Intermodulation
Distortion
0,08% at
rated output
0,03%
at ½ rated output
Input
Sensitivity/Impedance (at 200 W output, 1 kHz):
Phono
1, 2 : 2,5 mV /47 k Ω
Aux
: 150 mV / 50 k Ω
Tape
1, 2 : 150 mV / 35 k Ω
Adaptor
: 150 mV / 35 k Ω
DIN
: 450 mV/ 95 k Ω
MIC
: 3 mV / 50 k Ω
Max. Input
Level (Phono): 500 mV
Output Level
(Tape Out) :
150 mV
(Phono, Aux at rated input)
200 mV (FM
400 Hz, 30% dev. Input: 1 mV)
150 mV (AM
400 Hz, 30% mod.input: 5 mV/m)
Output level
DIN Out: 40 mV (Phono at rated input)
Signal-to-Noise
Ratio (IHF, Input shorted, A-network, rated power):
Phono 1, 2
: 75 dB
Aux : 90 dB
Tape 1, 2
: 90 dB
Damping
Factor: 75 (1 kHz, 8 Ω)
Equalizer: RIAA ±0,2 dB
Bass Control
±10 dB at 50
Hz turnover frequency 150 Hz
±10 dB at
100 Hz turnover frequency 300 Hz
Midrange
Control
±6 dB at 1
kHz
Treble
Control
±10 dB at 10
kHz turnover frequency 3 kHz
±10 dB at 20
kHz turnover frequency 6 kHz
Loudness
Control (Volume control set at -33 dB position): +9 dB (100 Hz); =4 dB (10 kHz)
High
Filter: -10 dB at 10 kHz (12 dB/oct)
Low
Filter: -10 dB at 50 Hz (12 dB/oct)
Audio Muting
Effect: -20 dB; 0 dB;
-40 dB
Tape
Monitor: 1,2
Speaker
Switch: A, B, C, A+B, B+C, C+A, OFF
Tuning
Meter: 2
Power
Meter: 2
AC
Outlet: 3 (one switched 50 W &2
unswitched total 150 W)
Speaker
Terminal: One touch terminal
FM Muting /
Auto Lock: provided
MPX Noise
Filter: provided
IF Band
Filter: Narroe and Wide
Multipath
Filter: provided
Pre/Main
Amplifier: separable
Adaptor
Switch: provided
Power
Supply: AC 120 - 220 V 50/60 Hz
Power
Consumption: 850 W
Dimensions
(W x H x D): 580 x 186 x 447 mm (22 ¾" x 7 ½" x 17 ½")
Weight: 25,5 kg (56,2 lbs)