KENWOOD KA-990SD
¥ 79,800 (around 1984)
Commentary
A pre-main amplifier that uses Super DLD (Dynamic Linear Drive) circuit.
The Super DLD circuit is equipped with a newly developed supercharger and makes full use of the four power supply circuits of the DLD to form a powerful power supply.
Conventional DLD circuits use four left and right amplifiers and four power supplies, respectively, by switching between a high-power amplifier and a dedicated power supply, or a low-power amplifier and a dedicated power supply. This circuit has the effect of increasing the actual power supply capacity, and has the effect of doubling the power supply capacity when a low-power amplifier, which has a dominant influence on sound quality, operates. At SuperDLD circuits, however, the power supply circuit has been further strengthened, and with the supercharger, energy can be supplied from a high-power dedicated power supply, which had been suspended when a low-power amplifier operates, when a low-power amplifier operates, and also from a low-power dedicated power supply, which had been suspended when a low-power amplifier operates.
As a result, the power supply capacity is always the mixed value of the four power supplies at any output, making it possible to reproduce clearer and heavier sound.
It is equipped with 8 input terminals and an adapter IN-OUT connection to a graphic equalizer.
It is equipped with a CD direct switch. In the CD direct position, the input selector, mode and subsonic contact switches and the balance volume jump. By simplifying the signal path, high quality playback is possible.
The design concept of the Σ drive is unchanged and the Σ drive TypeB is adopted in pursuit of usability.
By extending the NF loop to the speaker terminal, parts which cause distortion and sound quality degradation are put in the NF loop, and the performance at the speaker terminal of the amplifier is improved.
In addition, all GND lines are concentrated at one point on the speaker terminal of the amplifier to suppress the increase of mutual interference caused by GND line patterns and wires.
ICL High GmFET A differential input and IC-based equalizer amplifier is used.
The grounding section, which especially affects the sound quality, uses a latent space with a cross-sectional area six times larger than that of the conventional one with 26 single wires of 0.26 mm in diameter.
There was not only black model but also silver model.
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Model Rating
| Type | SuperDLD Integrated Amplifier | ||||
| Rated Output (Both Channel Operation) |
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| Total harmonic distortion rate (20 Hz to 20 kHz) |
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| Intermodulation distortion factor (60 hz : 7 khz = 4 : 1) | Tuenr, AUX, Tape → SP terminals : 0.004% (8 Ω at rated power) | ||||
| Frequency characteristic | Tuner, AUX, Tape → SP terminal : DC ~ 200 khz + 0 -3dB | ||||
| Damping factor (50 Hz) | 1000 | ||||
| Input Sensitivity / Impedance | Phono MM : 2.5mV/47k Ω Phono MC : 0.2mV/100 Ω Tuner, AUX, Tape : 150mV/47k Ω Adaptor In : 150mV/47k Ω |
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| Signal-to-noise ratio (IHF-A) | Phono MM → SP terminal : 88 dB Phono MC → SP terminal : 70 dB (250 μ V) Tuner, AUX, Tape → SP terminal : 108 db |
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| Tone control | 200 Hz : 100 Hz + / - 10 dB 3 kHz : 10 kHz ± 10 dB |
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| Loudness control | + 9 dB (100 Hz, Volume-30dB) | ||||
| Subsonic filter (-3dB) | 18 Hz, 6dB/oct. | ||||
| Rise time | Tuenr, AUX, Tape → SP terminals : 1.7 μ s | ||||
| Slew rate | Tuner, AUX, Tape → SP terminal : ± 100 V / μ s | ||||
| Output bandwidth (0.04% distortion factor) | Tuner, AUX, Tape → SP connector : 5 hz to 50 khz | ||||
| Phono maximum allowable input (1 kHz, THD 0.003%) |
Phono MM:200mV Phono MC:15mV |
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| Phono RIAA deviation (20 Hz to 20 kHz) | ± 0.3 dB | ||||
| Output Level / Impedance | Adaptor Out : 150mV/330 Ω Tape Rec : 150mV/330 Ω |
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| Pwer | 100 VAC, 50Hz/60Hz | ||||
| Rated power consumption (Electrical Appliance and Material Control Law) | 230W | ||||
| Power outlet | Power switch interlock : 2 systems, 100W Power switch not linked : 1 system, 400W |
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| External dimensions | Width 440x Height 143x Depth 383 mm | ||||
| Weight | 11.0kg |