DIATONE DA-U550
¥ 43,000 (released in 1973)
¥ 45,000 (around 1974)
Commentary
A pre-main amplifier developed according to the orthodox way, avoiding coloring in all aspects of performance, function and design.
A single-stage, pure complimentary service OCL circuit is used in the circuit structure to minimize changes in sound quality by simplifying the signal path as much as possible.
All parts have extra space, especially the power transistor has been upgraded to Pc40W, and the radiator is one size larger than the conventional one.
Low-impedance speaker drives are also designed to ensure that the speakers are driven in the best possible condition.
It is equipped with separate terminals for preamp output and power amplifier input, and can be used separately with one slide switch.
A high-voltage low-noise silicon transistor is used for the equalizer circuit.
Two MIC input terminals and REC terminals are installed.
BAX-type deformation is used for tone control. Variable type is 11-position click-stop type.
It is also equipped with a loudness control and a high-cut filter.
There was a wood case as an option sold separately.
Model Rating
Type | Pre-main amplifier | ||
Power Amplifier Unit | |||
Output |
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Harmonic distortion factor | 0.8% (at rated output) 0.06% at 1W output |
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Cross modulation distortion factor | 0.18% at 1W output | ||
Power bandwidth | 10 Hz to 50 kHz | ||
Frequency characteristic | 10 Hz to 50 kHz -0.5 dB | ||
Residual noise | 0.3mV | ||
Input Sensitivity / Impedance | 1V/50k Ω | ||
Preamplifier Section | |||
Input Sensitivity / Impedance | Phono : 2.5mV/50k Ω Mic : 2mV/50k Ω Aux, Tuner, Playback : 150mV/50k Ω |
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Output level | Rec out:150mV Pre out:1V |
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Frequency characteristic | Phono : RIAA ± 0.5 dB Aux : 20 Hz to 30 kHz ± 0.5 dB |
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Tone control | Bass : ± 10 dB (100 Hz) Treble : ± 10 dB (10 kHz) |
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High-cut filter | -6dB/oct(8kHz) | ||
Equalizer allowable input | 130mV(1kHz) | ||
Equalizer input conversion noise | -118dB | ||
<General> | |||
Power consumption | 50W | ||
External dimensions | Width 380x Height 133x Depth 301 mm | ||
Weight | 7.7kg | ||
Separately Sold : Wood Case CA-550 (¥ 6,500) for 550 Series | |||
External dimensions | Width 445x Height 165x Depth 297 mm |