Exceptinal
Stability of Amplification achieved Constant Current Driving System
The KA-6004
achieves an over-all high level of reliability in every performance phase. If
only the strictest requirements are met by each component, then they are
included in the full assembly potential of this outstandingly unique amplifier.
For example, the pre-amplifier uses a new type of can seal (metal cased)
transistor which is capable of off-setting usual characteristic deterioration
in S/N ratio resulting from humidity and temperature wear. Low noise PNP
transistors have been attached to the top of the equalizer circuit. Also,
super-high nichrome evaporated metal film resistors have been used in the
feedback circuit in the equalizer stage. Each error thus occurs only within
±1%. These same resistors are also only equipped in all other significant
circuits to vastly improve S/N and block S/N age deterioration.
Linear
Frequency Power Output Kept 40 W in 20 Hz to 20 kHz
Kenwood has
been improved in output indication. In the conventional way, output was
indicated in just one point of 1 kHz. However, in Kenwood's latest way of
improving over-all quality guaranteed output is indicated in the entire range
of audio frequency of 20 Hz to 20 kHz, i.e. the output is indicated in
"minimum point", but not in "maximum point".
The maximum
output is a performance figure that implies the dynamic range of the power
amplifier, therefore, only the output of 1 kHz will imply the imperfect
performance of the amplifier because the output of any amplifier is usually
best near 1 kHz. However, as described in the preceding, KA-6004 has the
circuits to allow the simultaneous indication of entire performance. With an
all stages direct-coupled circuit provided, the output linearity in low pass
will be shown by power output data
Higher
Reliability Achieved by Strictly Selected Components
The
pre-amplifier employs a new type of can seal transistors that are capable of
precluding the characteristic changes, i.e. the characteristic deterioration of
S/N caused by humidity and temperature. At the top of equalizer circuit, low
noise type PNP transistors are equipped.
The feedback circuit in the equalizer stage employs super-high precision
nichrome evaporated metal film resistors, each error within ±1%. The nichrome
evaporated metal film resistors are equipped in all other important circuits to
prominently improve S/N and preclude age deterioration of S/N.
1
Pure-complementary
Circuit + Constant Current Driving
The KA-6004
employs Kenwood's exclusive Constant Current Driving system in the
pure-complementary and direct coupling driver stage. The highest stability in
the amplification is now obtainable. By minimizing crossover distortion and by
improving phase characteristics, the KA-6004 guarantees superb performance
quality from ultra low range to far above the limit of audio frequency. It also
prevents performance from deterioration caused by the deviation in power
voltage. Kenwood has overcome the last problem-instability-remaining in direct
coupling amplification. The refined reproduction is fully enjoyable.
2
Protection
Circuit
All stages
direct-coupled circuit in KA-6004 includes constant current driver circuit
capable of amplifying from DC. The driving way will amplify faithfully the
superlow pass, i.e. plus minus several
Hz of the frequency picked up by cartridge on bowed record plate and
wow-fluttered turntable, thus the faithful amplification will permit
unnecessary critical load on speaker. In addition, if direct current input
should be applied, burning of voice coil may by caused. To prevent the preceding troubles in KA-6004,
a protecting circuit is employed to cut superlow pass of 10 Hz or less in order
to protect speaker against overload.
Exceptional
Dynamic Range
The
equalizing stage of preamplifier has been entirely redesigned to obtain
exceptionally wide dynamic range. The KA-6004 assures 420 mV p-p maximum input
level (at 1 kHz). Any fortissimo peak can faithfully reproduced without
saturation. Further, thanks to the minimized RIAA deviation of within ±0,2 dB,
playback with real high fidelity is guaranteed.
Attenuator
Type Tone Control
Attenuator
is employed in tone control, +10 dB to -10 dB is covered by 2 dB controlled.
Left and right characteristics are correctly coincided, so that no unbalance
will be caused in tone control.
In
conventional volume type, frquency characteristic is not perfectly flat even at
zero degree, but is waved. In KA-6004, with tone control positioned at
"Off", tone control circuit is neglected, so that frequency
characteristic is kept correct.
Noise Filter
Low cut
filter has two turnover points, i.e. 40 Hz and 80 Hz controlled, and sharp
attenuation characteristic of 12 dB/oct. The filter will also protect speaker,
with protection circuit associated, againt large signal inputted in low pass.
High cut
filter has a higher turnover point, i.e. 7 kHz which will reduce noise only
without damaging desired tone, and an easy attenuation characteristic of 6
dB/oct.
Input
Selector
The KA-6004
is versatile for input program sources. It features input jacks for 2 pairs of
phono, 2 pairs of Aux, tuner and microphone.
A program source on operation is shown by luminous indicator on the
front panel.
Two Systems
of Tape Monitor
Two systems
of tape monitor circuits, i.e. A and B are provided to allow simultaneous
activation of two decks. Mutual dubbing
is easily allowed by switching only.
Microphone
Input
Mic input
terminals are equipped on front paanel, so that right-side two systems of
microphones will allow so easier operation. Since selector positions are
independent, the input may be used sufficientlyfor microphone amplifier.
Push Button
Type Speaker Selector
Two pair of
speaker terminals, i.e. A and B may be changed by push-button correctly locked.
With A and B pushed at the same time, simultaneous activation is allowed.
9
One Touch
Type Speaker Terminals
Speaker
terminals are of one touch connection type which allow easy and correct
coupling, so that the system will eliminate any trouble on speaker connection.
Loudness
Control
On a level
of -30 dB, low pass is 100 Hz with +8db and high pass in 10 kHz with +3 dB,
both provided higher than the conventional, so that the control will supplement
low and high pitched tones.
Specifications
Continuous
Power Output:
Both channel
driven:
40/40
watts into 8 Ω at any frequency from 20 - 20,000 Hz
43/43
watts into 8 Ω at 1,000 Hz
57/57
watts into 4 Ω at 1,000 Hz
Each channel
driven:
55/55
watts into 8 Ω at 1,000 Hz
70/70
watts into 4 Ω at 1,000 Hz
Dynamic
Power Output (IHF):
130
watts per channel into 8 Ω at 1,000
Hz
220
watts per channel into 4 Ω at 1,000
Hz
Total
Harmonic Distortion:
less than
0,5% at rated output from 20 - 20,000 Hz;
less than
0,05% at -3 dB rated output
Intermodulation
Distortion (60 Hz; 7,000 Hz; 4:1):
less than
0.3% at rated output;
less than
0,05% at -3 dB rated output
Power
Bandwidth (IHF): 10 Hz to 50,000 Hz
Input
Sensitivity/Impedance (for rated output, at 1,000 Hz):
Phono
1: 2,5 mV/50 kΩ
Phono
2: 2,5 mV/ 50 kΩ
Tuner: 200 mV/ 100 kΩ
Aux 1,
2: 200 mV/ 100 kΩ
Tape
Play A & B: 200 mV/ 100 kΩ
Mic: 3
mV/50 k Ω
Main
Amp. Input: 1 V/ 50 kΩ
Recording
Output (below rated input):
Tape Rec A
& B: 200 mV
DIN
connector: 40 mV
Signal-to-Noise
Ratio (below rated output):
Phono 1
& 2: 68 dB
Mic: 70 dB
Tuner: 75 dB
Aux 1 &
2: 75 dB
Tape Play A
& B: 75 dB
Noise
at Minimum Volume Control: 0,3 mV at 8 Ω, 0,000012 milli watts
Damping
Factor: 32 at 8 Ω load; 64 at 16 Ω load
Speaker
Impedance: accepts 4 to
16 Ω
Bass
Control: ±10 dB at 100 Hz (with 2 dB
step switch)
Treble
Control: ±10 dB at 10,000 Hz (with 2 dB
step switch)
Low
Filter: 40 Hz and 80 Hz cut off, 12 dB
per octave
High
Filter: 7,000 Hz cut off, 6 dB per octave
Loudness
Control (-30 dB): +8 dB at 100 Hz; +3 dB
at 10,000 Hz
Switches:
Speaker
: A, B (ON-OFF at push switch)
Selector
: Aux1, Aux 2, Tuner, phono 1, Phono 2,
Mic
Mode : left, Right, Stereo, REV, Mix
Tape Monitor
: Dubbing, (A→B), A Play, Source< B
Play, Dubbing (B→A)
Others
: Low & High Filter, Loudness,
Muting, Power
AC
Outlets: 1 switched & 3 unswitched
Power
Requirement: 110 - 120 V/220 - 240 V AC,
50/60 Hz
Power
Consumption: 235 watts at full power; 15
watts at no signal
Dimensions
(W x H x D): 435 x 153 x 300 mm (17-1/8
x 6-1/32 x 11-13/16 inch)
Weight: 11,5 kg (25,4 lbs)