KENWOOD D-3300A
¥ 198,000 (released in 1986)
Commentary
This digital pre-main amplifier has a built-in D/A converter inside the amplifier and was developed to express the quality of CD in 100% sound.
The D/A converter consists of a 4 x over-sampling digital filter, a left and right independent ladder network type D/A converter, and a 7th Butterworth FDNR type discrete low-pass filter.
To support digital sources that use different sampling frequencies, a built-in PLL data demodulator that automatically switches between 32 kHz, 44.1 kHz, and 48 kHz clock (sync) frequencies is incorporated.
A dynamic linear drive circuit is used in the amplifier section.
This circuit uses two amplifiers for the output, a low-power amplifier and a high-power amplifier. Most of the signal is processed by a low-distortion low-level amplifier to improve the expressive power. In addition, this low-power amplifier, which can be used up to approximately 50W, is driven by a huge power supply that can output more than 300W. This reduces the impedance of the power supply and reduces the influence of speaker load fluctuations.
Based on the policy that the power supply part is designed as a part of the power amplifier, a new VIG (Voltage Interface Gate) circuit that interfaces between the amplifier part and the power supply part is adopted to provide power supply energy that is not affected by power supply fluctuations.
In addition, the VIG circuit keeps the voltage between the base and the emitter of the final transistor constant, suppressing the effect of the fluctuation component generated by the final operation of the amplifier on the pre-driver stage and the driver stage. This makes the signal transfer between the pre-driver stage and the driver stage smooth and enables purer signal amplification.
Kenwood's original Σ drive has been introduced, and the earth point is concentrated on the speaker terminal of the amplifier, and the operation reference point of the amplifier is clarified. As a result, digital noise generated from electric products and digital equipment using the microcomputer does not flow into the signal system of the amplifier, and clear reproduction sound is obtained even at a very small level.
In addition, relays and switches up to the output terminal are also incorporated into the NF loop, resulting in an amazing damping factor.
The equalizer circuit is equipped with a dual equalizer system with dedicated equalizers for MC cartridges and MM cartridges.
The equalizer amplifier for MM has an FET input with Hi-gm = 40 ms ultra-low noise, and the equalizer amplifier for MC has an FET input with γ' bb = 4 π ultra-low noise. Both of these can be independently operated, resulting in an excellent low distortion factor.
The power supply section is equipped with a large transformer with vibration-proof pitch and an electrolytic capacitor with a total capacity of 72000 μ F. Independent dedicated windings are used for the D/A converter and equalizer section.
On the circuit side, the high-performance output capacitor is made into a discrete configuration to expand the regenerative bandwidth characteristics and current supply capability.
The digital input is the Route 3 of optical digital, coaxial digital and DAT monitor, and the analog input is equipped with 8 systems such as phono input, tape and tape Route 3.
It is equipped with a line straight circuit that can bypass the tone control, NF-CR type tone control with excellent variation characteristics, winking power indicator, continuously variable loudness control, etc.
It uses a luminous pointer that displays the indicated position of the volume knob.
In addition, newly developed insulators are used.
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Model Rating
| Type | Digital integrated amplifier | ||||
| Amplifier Unit | |||||
| Rated Output (Both Channel Operation) |
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| Total harmonic distortion factor (20 Hz to 20 kHz) |
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| Cross modulation distortion factor | 0.003% (60 Hz : 7 kHz = 4 : 1, at rated output, 8 Ω) | ||||
| Frequency characteristic | 1 Hz ~ 100 kHz + 0 -3dB (Overall (AUX → SPKR) CP-301A) 1 Hz ~ 150 kHz + 0 -3dB (Overall (AUX → SPKR)) |
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| Phono RIAA deviation | 30 Hz to 20 kHz ± 0.2 dB | ||||
| Output bandwidth | 5 Hz ~ 50 kHz (8 Ω at 0.04% Distortion Rate) | ||||
| SN ratio (IHF-A at rated output) | Phono MM:87dB(2.5mV) Phono MC : 78 dB (250 μ V) CD, Tuner, AUX, Tape Play : 110 dB |
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| Tone control |
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| Filter | Subsonic (-3dB) : 18 Hz, 6dB/oct | ||||
| Loudness control | 100 Hz : 0 dB to + 8 dB (Volume -30dB) | ||||
| Damping factor (50 Hz) | 1000 | ||||
| Input Sensitivity / Impedance (at rated output) |
Phono MM : 2.5mV/47k Ω Phono MC : 0.1mV/100 Ω CD, Tuner, AUX, Tape Play : 150mV/47k Ω |
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| Phono maximum allowable input (Phono → Tape Rec) |
MM : 210 mV (1 kHz, THD 0.003%) MC : 8 mv (1 khz, THD 0.003%) |
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| Output Level / Impedance | Tape Rec : 150mV/220 Ω | ||||
| D/A Converter Unit | |||||
| Sampling frequency | 32 kHz, 44.1 kHz, 48 kHz (automatic switching) | ||||
| Signal-to-noise ratio | 105dB(EIAJ) | ||||
| Distortion factor | 0.003%(EIAJ) | ||||
| Channel separation | 115dB(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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| <General> | |||||
| Pwer | 100 VAC, 50Hz/60Hz | ||||
| Rated power consumption | 430W (Electrical Appliance and Material Control Law) | ||||
| Power outlet | Power Switch Interlock : 2, 100W Power switch not linked : 1, 400W |
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| External dimensions | Width 475x Height 170x Depth 424 mm | ||||
| Weight | 19.7kg | ||||
| Attachment | Optical and digital cables | ||||