A far higher grade
stereo amplifier than any previous Kenwood model, the KA-7002 is a tribute to
Kenwood's philosophy that only the
purest sound satisfies listener's ears.
By use of the direct coupling circuitry with pure complementary-symmetry
driver stage, which means all interstage coupling capacitors are eliminated,
its sound quality is purified to ensure ideal frequency response, very lowest
Im distortion and improved damping factor characteristics. The KA-7002's
superiority has been finally verified and guaranteed through the series of
listening tests as well as through the technical measuring and simulations.
That means every figure, every feature of KA-7002 is hundred percent alive.
Special FEATURES
All stages direct
coupling circuitry and pure complementary symmetry driver stage ensure superb
frequency response, ultra-wide power bandwidth, large damping factor, lowest IM
distortion, etc.
Improved NF type
equalizeer stage for wide dynamic range.
2dB step type
accurate tone controls with 2 step turnover switches and complete defeat
switches.
Low filter either at
40 Hz or 80 Hz with sharp 18dB/oct
cutoff.
Impedance selector
for phono input (30 or 50 Kohms)
Low level phono
input (0,06mV).
Exclusive Null
Balancer brings perfect stereo balance.
3 pairs speaker
outputs and front panel selector switch.
Tape monitor and
dubbing switch for 2 tape decks.
4 channel input,
output terminals and volume control.
Pre-amplifier output
jacks and main amplifier input jacks.
Excellent Frequency
Response
Since KA-7002
employs full stage direct coupled circuit in the main amplifier unit, without
coupling capacitors, DC amplification becomes almost possible. Frequency
response is, therefore, largely improved and other various characteristics are
enhanced with sufficient feedback. The output impedance is always flat, from
ultra-low frequency to high-frequency, and has no boost in low frequency range
due to output capacitor.
Stable Output &
Low Distortion Factor
In an asymmetrical
power supply using output capacitors, the maximum output decreases in the
ultra-low path range due to limited capacitance. The power supply in KA-7002 is
symmetrical on both upper and lower sides. The output in the ultra-low path
range will not decrease and the output is always stable. Since transistor
functions are the same in the upper and lower half cycle of the input signal,
cross-over distortion and switching pulse components can be eliminated, which
has been inevitable in conventional semi-complementary circuits. Consequently,
distortion at the low output level becomes very small.
High Damping Factor
In order to enhance
DC stability, the differential amplifier circuit is composed of high
temperature characteristic transistors in the first and pre-drive stage and by
use of zener diode the supply voltage in the first stage circuit is stabilized
with 100% DC feedback applied. This eliminates deterioration of
mechanicalstatic due to a direct current flowing in the voice coil of the speaker. Also, this differential
amplification is done in the direct coupled circuit, good phase characteristics
are attained. And damping factor with reference to the speaker is improved up
to 45 (at 8 ohms) without descending down at lower frequency range.
Three Stage Direct
Coupled NF-Type Equalizer
The equalizer
circuitry is made up of 3-stage direct coupled, NF-type having a wide dynamic
range. This was developed from the circuitry in the KA-6000 whose excellent
characteristics and power voltage, a wide dynamic range is obtained.
Precise Tone
Controls
Tone control is
variable in 2dB steps. Turn over roll off is switchable into 2 stages, 150 or
300 Hz in Bass and 2 kHz or 6 kHz in Treble. In order to eliminate slight
osoillation at flat position, the cancellation can be operated by both level
control knob and the independent defeat switches.
Protection Circuit
Asthe main unit
consists of direct coupled circuits, the protection circuit differs from
conventional layouts in which the first stage power supply is disconnected.
This type system suppresses current to the output transistors by PC detection
system using a current limiter through which no input signal is applied in the
driver stage when large current flows to the output transistor. When this
protection circuit operates, no DC voltage is produced at the output terminal.
Sharp Cut Filter
In order to
eliminate noise due to resonance of arm, motor noise wow and flutter, scratch,
etc., without deterioration of tone quality an 18 dB/oct filter is built-in.
Also, in order to prevent schock noise created during switch operation,
strictly selected tantal solid capacitor with a leak current below 1 mA is
used.
Mode Switch For
4-channel Reproduction
Besides the
conventional 2-channel use, the mode switch circuit has input/output terminals
and control volume for 4-channel stereo and functions as a 4-channel control
amplifier.
Perfect Balance
Control System
In order to obtain
left and right output balance, a sound source has been conventionally set to
the center of the right and left speakers by setting Mode to Mix. In the
KA-7002 a null balance system has been adopted so that sound is disappeared
when right and left levels become even, as a result, total balance from the
cartridge to the amplifier can be fully obtained by manipulation of the Null
Balance while playing monaural disc.
Unlimited Capability
and Usability of KA-7002
The concentrated
terminals on the rear panel show the KA-7002 is capable for all the program
sources and has wide usability which meets any of the critical audiophile'
requirements.
The KA-7002 is able
to play the leading role of the highest music system.
Phono 1 - Connect
moving magnet type cartridge. Load impedance is switchable (30 or 50 kohms)
Phono 2 - Input
sensitivity of 0,06 mV. Low output moving coil type cartridge can be dirctly
connected.
Mic - By 2
microphones, stereophonic reproduction is enjoyable. In case one mike is used,
the sound is made monaurally from both speakers.
4-Channel - Input
and output terminals for 4-channel reproduction. With Mode Switch equipped on
the front panel, KA-7002 can control 4-channel music system.
Normal/Separate
Switch - At normal side, pre-amplifier and main-amplifier are combined. At
separate side, they are individually separated.
Tape Recorder - 2
pairs of tape-play and tape-rec jacks and 2 DIN connectors. Dubbing and
monitoring of A→B, B→A decks are available.
Speakers - 3 pairs
of speaker system are connectable. Selector switch on the front panel offers 5
varietes of thier combinations.
AC Outlets - 3
switched outlets for total 300 watts and 1 unswitched for 100 watts.
Specifications
Total Dynamic Power
(both channel, IHF):
196 watts at 4 ohms
170 watts at 8 ohms
Continuous Power
Output (each channel driven):
80/80 watts at 4
ohms
70/70 watts at 8
ohms
Continuous Power
Output (both channel driven):
68/68 watts at 4
ohms
50/50 watts at 8
ohms
Harmonic
Distortion: less than 0,5% at rated
output from 20 Hz to 20,000 Hz
Intermodulation
Distortion (60 Hz & 7,000 Hz ; 4 : 1):
At rated output :
Less than 0,3%
At -3 dB rated
output : less than 0,1%
Frequency
Response: 20 Hz to 50,000 Hz ±1 dB
Sensitivity (for
tared output at 8 ohms load):
Phono 1 : 2,5 mV
Phono 2 : 0,06
mV or
2,5 mV
Mic : 2,5 mV
Tuner, Aux 1, 2
: 200 mV
Tape A, B : 200 mV
Main amp input : 1 V
Input Impedance (at
1 kHz):
Phono 1 : 30 or 50
kohms
Phono 2 : 200 ohms
(0,06 mV); 50 kohms (2,5 mV)
Mic : 50 kohms
Aux 1, 2 : 100 kohms
Tape A, B : 100
kohms
Main amp input :
50kohms
Signal-to-Noise
Ratio (below rated output):
Phono 1 : 65 dB
Phono 2 : 45 dB
(0,06 mV); 65 dB (2,5 mV)
Mic : 67 dB
Aux, Tuner, Tape
: 77 dB
Noise at minimum
volume control 0,5 mV at 8 ohms or 0,0003 milliwatts
Damping Factor: 90 at 16 ohms load; 45 at 8 ohms load
Low Filter (for
rumble): 80 Hz and 40 Hz cutt-off, 12 dB
per octave
High Filter (for
scratch): 7,000 Hz cut-off, 12 dB per
octave
Bass Control: ±10 dB at 100 Hz with 2 dB step switch (tone
control switch at 300 Hz)
Treble Control: ±10 dB at 10,000 Hz with 2 dB step switch
(tone control switch at 2 kHz)
Turnover roll off
freq:
Bass : 150 Hz, 300
Hz, defeat
Treble : 2 kHz, 6
kHz, defeat
Input:
Pair of Phono 1,
Phono 2; Mic, Aux 1-2; Tape Play A, B; 4 channel and main amp.inputs
Output: 3 pairs of stereo speaker outputs (4 to 16
ohms); pre-amplifier outputs; headphone jack; low level mono output; Tape
recording outputs A and B, DIN standard tape Rec/Play connector A and B;
switched and unswitched AC outlets and 4 channel output
Power
Requirement: AC 110 - 120 V, 220 - 240 V, 50/60 Hz
Power
Consumption: 15 watts at no signals ,
275 watts at full power
AC Outlets: 3 switched, 1 unswitched
Dimensions (W x H x
D): 408 x 134 x 280 mm (16-15/16'' x
5-5/32'' x 11-1/32'')
Weight: 10 kg
(22,1 lbs)
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