KENWOOD KA-7050R
¥ 88,000 (around 1993)
Commentary
A pre-main amplifier with fully reinforced final stages such as twin-drive multiple final stage and MOS-FET.
The final stage (power amplification) stage of the power section has been revised to a twin drive multiple final stage configuration.
This is a configuration in which two dedicated drivers are arranged in parallel for each final stage of parallel push-pull configuration, and excellent drive performance is obtained even for low-impedance speakers.
MOS-FET is used as the final stage element.
Since MOS-FET has high input impedance, it is possible to break the electrical coupling of each stage, and it has excellent characteristics such as good high-frequency characteristics and good linearity of small-signal amplification.
An internal balanced circuit is used to prevent external noise and line noise from entering.
This is designed to isolate the signal path and ground path by converting the balance of the unbalanced signal right after the input selector. Although it is an unbalanced input, it has the characteristics of a balanced transmission with an amplification system and prevents noise from entering.
In addition, common mode noise is eliminated by performing one stage amplification with two amplifiers, and noise from the ground line is prevented because no feedback resistor is installed.
A 6-gang balanced volume is adopted for the volume, and the performance against common mode noise is improved by the volume which constitutes the ground free structure.
The gain control volume of the amplifier is placed behind the two main volumes of one channel, and the gain is adjusted by two stage configuration.
The volume knob uses a cast-cut thickness type to prevent adverse effects due to sound pressure.
A newly developed barrel core bobbin transformer is used for the power supply.
The barrel core bobbin transformer reduces not only the leakage flux by the magnetic flux feedback by the shield plate, but also the flux loss of the transformer itself is reduced and the high-frequency component of the output current is suppressed, so that the bare interference in small signal amplification is minimized.
In addition, by adopting the core shape of the transformer winding (almost circular without corners), the fit between the bobbin and coil is improved, and vibration is greatly reduced compared with conventional products.
A pure signal ground line is used to connect the ground line of the signal system and the ground line of the power supply with the speaker terminal in order to prevent the adverse effect of power supply ripple and various noise components.
This allows only pure signals to flow through the ground line of the signal system, enabling purer signal amplification.
The input selector section employs a relay selector that uses six inert gas-filled relays to reduce adjacent interference between signals.
It is equipped with gold plated RCA pin connector and banana compatible large speaker terminal.
A reinforcement bridge is attached under the top plate to increase the strength of the case.
System remote control is included.
.JPG)
Model Rating
| Type | Integrated amplifier | ||||||
| Rated Output (20 Hz to 20 kHz, Both Channel Operation) | 110W + 110W (6 Ω, THD 0.008%) 100W + 100W (8 Ω, THD 0.008%) |
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| Dynamic Power | 360W + 360W (2 Ω) 260W + 260W (4 Ω) 150W + 150W (8 Ω) |
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| Total harmonic distortion factor (8 Ω, 100W) | 0.008% (20 Hz to 20 kHz) | ||||||
| Frequency characteristic | Overall (LineCD) : 5 Hz ~ 100 kHz + 0 -3dB | ||||||
| Signal-to-noise ratio |
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| Input Sensitivity / Impedance (at rated output) |
Phono MM : 2.5mV/47k Ω Phono MC : 0.2mV/100 Ω DAT, CD, Tuner, AUX, Tape Play : 200mV/47k Ω |
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| Phono maximum allowable input (Phono → Tape Rec, 1 khz, THD 0.08%) |
MM:120mV MC:10mV |
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| Output Level / Impedance | Tape Rec : 200mV/0.22 Ω | ||||||
| Power supply voltage | 100 VAC, 50Hz/60Hz | ||||||
| Rated power consumption (Electrical Appliance and Material Control Law) | 300W | ||||||
| Maximum external dimensions | Width 440x Height 163x Depth 403 mm | ||||||
| Weight | 15.4kg |