KENWOOD DA-9010
¥ 91,100 (around 1988)
Commentary
A pre-main amplifier with built-in D/A converter incorporating pure signal and ground line technology.
The conventional amplifier ground line mixes the music signal with the power supply current, which adversely affects sound quality. However, we have developed our own pure signal ground line to prevent this.
The power supply ripple and various distortion components are all guided to the speaker terminal by a dedicated ground line, and all the ground lines join together for the first time. Therefore, only pure signal flows through the main ground line that amplifies the signal, enabling pure amplification.
A grounded balanced transmission circuit is used between the D/A converter and the power amplifier to eliminate the digital noise transmitted through the ground.
When digital signals are transmitted from a digital device to an amplifier, music signals, clock signals and various control signals are mixed and sent over a single cable.
In order to prevent significant degradation of the clock accuracy at the amplifier side due to this phenomenon, a twin quartz PLL with two stages of PLL is mounted.
In the first stage, external noise and jitters due to the input path are absorbed and reliable data acquisition is performed, and a tentative master clock is generated.
The second stage uses a crystal oscillator to improve the accuracy of the master clock in order to read data with a higher time accuracy.
This allows for more accurate D/A conversion.
A DPAC (Digital Pulse Axis Control) is applied to the digital circuit.
This is a method of time adjustment including the calculation speed of the digital filter. All the jitter component is absorbed immediately before the D/A converter, the signal level is read with an accurate clock, and more faithful D/A conversion is performed.
The D/A converter consists of an 8-times oversampling 18-bit digital filter and an 18-bit linear dual D/A converter.
A real-step full-bit D/A converter improves the accuracy of the level axis.
The power supply uses a large transformer of 440 VA and 6 kg and a power transformer of 15,000 μ Fx2.
The power block is a parallel push-pull type using four single-channel high-power transistors of Pc = 120W for the final stage in order to increase the low-impedance driving capability.
It has a source direct function.
It comes with a remote control and can operate muting, D/A conversion and volume using a microcomputer.
In order to separate the analog signal from the microcomputer control current such as clock component, a photo coupler is inserted between the microcomputer control output and the signal system. The microcomputer output is used for optical transmission, and the microcomputer system and analog system are electrically separated.
.JPG)
Model Rating
| Type | Digital integrated amplifier | ||||||
| Amplifier Unit | |||||||
| Rated output (20 Hz to 20 kHz Both channel operation, THD 0.015%) |
125W + 125W (6 Ω) 105W + 105W (8 Ω) |
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| Dynamic Power | 340W + 340W (2 Ω) 230W + 230W (4 Ω) 140W + 140W (8 Ω) |
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| Harmonic distortion factor (CD, 8 Ω) |
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| Cross modulation distortion factor | 0.0035% (60 Hz : 7 kHz = 4 : 1, at rated output, 8 Ω) | ||||||
| Frequency characteristic | 5 Hz ~ 90 kHz + 0 -3dB (Overall (Line → SP)) | ||||||
| Phono RIAA deviation | 20 Hz to 20 kHz ± 0.3 dB | ||||||
| Signal-to-noise ratio |
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| Tone control | Bass : 100 Hz, ± 10 dB Treble : 10 kHz, ± 10 dB |
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| Subsonic filter | 18 Hz, 6dB/oct. | ||||||
| Bus intensifier | 9 dB (20 Hz), 3 dB (100 Hz) | ||||||
| Damping factor | 150(50Hz) | ||||||
| Input Sensitivity / Impedance (at rated output) |
Phono MM : 2.5mV/47k Ω Phono MC : 200 μ V/100 Ω DAT, CD, Tuner, AUX, Tape Play : 150mV/47k Ω |
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| Phono maximum allowable input (Phono → Tape Rec) |
MM : 200 mV (1 kHz, THD 0.008%) MC : 15 mv (1 khz, THD 0.008%) |
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| Output Level / Impedance | Tape Rec : 150mV/2.2k Ω | ||||||
| D/A Converter Unit | |||||||
| Sampling frequency | 32 kHz, 44.1 kHz, 48 kHz (automatic switching) | ||||||
| Signal-to-noise ratio | 110dB(EIAJ) | ||||||
| Total harmonic distortion factor | 0.0015%(EIAJ) | ||||||
| Channel separation | 110dB(EIAJ) | ||||||
| Digital input / output | Optical received power : -14dBm to -23dBm Coaxial : 0.5Vp-p/75 Ω DAT Monitor : 0.5Vp-p/75 Ω Digital Out (Coaxial) : 0.5Vp-p/75 Ω |
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| <Video Part> | |||||||
| Rated input level / impedance | 1Vp-p/75 Ω | ||||||
| Rated output level / impedance | 1Vp-p/75 Ω | ||||||
| <General> | |||||||
| Pwer | 100 VAC, 50Hz/60Hz | ||||||
| Rated power consumption | 260W (Electrical Appliance and Material Control Law) | ||||||
| Power outlet | Power Switch Interlock : 1, 100W Power switch not linked : 2, 300W |
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| External dimensions | Width 440x Height 162x Depth 422 mm | ||||||
| Weight | 18kg | ||||||
| Attachment | Remote Controller RC-A9010 | ||||||