DIATONE DA-A7
¥ 60,000 (around 1976)
Commentary
A power amplifier of the Feature series released by Diatone.
It adopts a differential amplification 2-stage current mirror drive system and is designed with an emphasis on low distortion factor especially for small signals.
By combining a high-gain, low-distortion current mirror circuit and a power transistor with good linearity, the bare characteristics are improved. Moreover, a low distortion factor is realized by sufficient NFB.
High ft transistor and current mirror drive improve pulse rise characteristics.
The power supply section contains one 300 VA power transformer and two 63 V, 18000 μ F electrolytic capacitors.
Effective heat radiation is achieved by placing heat generating components such as a heat sink and power supply transformer outside the chassis.
Using a heat sink of 0.5 ℃ / W per channel, the temperature of the power transistor is kept low enough.
The protection relay is used as it is for changing the speaker.
As a result, the damping factor does not decrease as in conventional speaker switching switches.
It can be docked and remotely controlled with Feature series preamplifiers.
Model Rating
Type | Stereo power amplifier | ||||||||||
Output |
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Harmonic distortion factor | 0.1% (at rated output) 0.02% (20 Hz to 20 kHz at 1W output) 0.003% (1 khz at rated output of -3dB) |
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Intermodulation distortion factor (1W, 50 Hz : 7 khz = 4 : 1) | 0.03% | ||||||||||
Input Sensitivity / Impedance | 1V/50k Ω | ||||||||||
Frequency Response (0.5W, 0 dB-1 dB) | 10 Hz to 50 kHz | ||||||||||
Output Bandwidth (0.1% IHF Distortion) | 10 Hz to 50 kHz | ||||||||||
Damping factor | 100 | ||||||||||
Channel separation | 85dB(1kHz) 60dB(20kHz) |
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Residual noise | 0.25mV | ||||||||||
Muting time | 5 seconds | ||||||||||
Adaptive load impedance | 4 ~ 16 Ω | ||||||||||
Pwer | AC100V 50Hz/60Hz | ||||||||||
Power consumption | 185W (Electrical Appliance and Material Control Law) 270W at Rated Output (8 Ω) |
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External dimensions | Width 425x Height 170x Depth 225 mm | ||||||||||
Weight | 11.5kg |