Audio Database

The

DIATONE DA-U850
150,000yen(around the 1975 time)

Description
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It is the high-class Integrated Amplifier which adopted the whole page direct connection circuit.

The whole page direct connection pure contest OCL system has realized high power.
Moreover, about the temperature drift of output end direct-current voltage, the new magnification circuit which shows very few drifts in the large temperature range is adopted. Highly efficient-ization is measured using the part with large current capacity.

The super-low noise transistor developed with the low concentration diffusion technology of the Diatone is adopted as first rank differential amplification.
Compared with the conventional low noise transistor, a 1/f noise of about 2dB is improved, and the dynamic range is also improved.

The pair transistor to which the nakedness characteristic was equal is adopted as a power stage and a driver stage, and distortion at the time of an open-loop is lessened.
The distortion at the time of the Koide power decreased by this, and it has contributed to expansion of a dynamic range.

In order to intercept from a high fever and magnetism which are generated from a power block, it separates clearly and a pre-block is arranged in a front part. Furthermore, it is shielding.
It could maintain at a temperature lower 10 degrees C or more than a power block in the state of anticipated use by this, and the stability of a transistor with a high temperature dependence and the reliability of each part are raised.
The power part and the Puri part are connected with the bottom of both blocks, and have become little design of a secular change etc.

The presence control which can amplify inside compass in broadcloth at a 1dB step is carried.
A change (800Hz and 2000Hz) is possible for center frequency.

A tone control circuit separates a damping time constant circuit, and is considering it as the circuit composition from which a flat frequency response is acquired in the flat position.

The working range where a transistor is linear is wide, and, moreover, tone control amplifier and presence control have adopted amplifier with high stability independently, respectively.

22 contact Attenuator is adopted.
The characteristic of attenuation degree deflection and a gang error is less than 1.5dB to the degree of attenuation of 28dB with less than 1dB and the degree of attenuation of 30dB or more.

Power ratio 2.9.


Form Integrated Amplifier
<Power amplifier part>
Output (both ch operation)
20Hz - 20kHz : 130W+130W (4ohms)
90W+90W (8ohms)
1kHz: 140W+140W (4ohms)
95W+95W (8ohms)
THD 0.1% (at the time of rating)
0.05% (1 W:00)
Cross modulation distortion 0.05% (1 W:00)
Power bandwidth 10Hz - 30kHz
Dumping factor 80 (8ohms)
Remains noise 0.4mV
Input sensitivity/impedance 1V/60kohm
<Preamplifier part>
Input sensitivity/impedance
Phono1: 2.5mV/50kohm
Phono2: 2.5mV/30, 50, 75kohm
High Level Input: 150mV/50kohm
An Output voltage/impedance
Pre Out: 1V/1kohm
Rec1, 2 : 150mV/1kohm
THD 0.05%
Frequency response
Phono(RIAA STD): 20Hz-20kHz}0.3dB
High Level Input: 20Hz-20kHz+0 -0.5 dB
Presence control }3dB (800 or 2kHz)
Tone control Bass: }10dB (100 or 50Hz) (Turnover 500, 250Hz)
Treble: }10dB (10 or 20kHz) (Turnover 2.5, 5kHz)
Filter Low: 15 or 40Hz (12 dB/oct)
High: 9 or 15kHz (12 dB/oct)
Phono allowable input 320mV (distorted [ 0.1% ] 1kHz)
Input conversion noise Phono:-120dB(V)
High Level Input:-100dB(V)
<Synthesis>
Power source AC100V 50Hz/60Hz
Power consumption 200W
Dimensions Width 425x height 148x depth of 387mm
Weight 17.5kg
Rating of a mode