Audio Database

The

DIATONE DA-A15DC
130,000yen(around the 1978 time)

Description
 
It is the stereo power amplifier which realized direct-current-ization.

The phase distortion of a low-pitched sound region was thought as important, and direct-current system which excluded entirely the condenser used as the damping time constant of a magnification circuit is adopted.
Moreover, in the high region, the frequency bandwidth before applying NF is improved, distortion is decreased, and little distorted play is enabled over the broadband. Furthermore, NF is made easy to distribute the gain before applying NF the best for each of each stage, and to apply to high frequency.

The characteristic has gathered well, moreover dual FET which has large gm (mutual conductance), and extremely few noises of itself is developed and adopted, and high S/N-ization is attained.
Moreover, operation which was stabilized very small by adoption of this dual FET as for the drift of the output end electric potential accompanying direct-current-izing is obtained.

2 monophonic construction which constituted the power source according to right-and-left channel and two sets of monophonic amplifier on the same chassis is adopted, and the extensive improvement of the separation is carried out at the same time it loses the mutual intervention of a power-source part.

The heat sink of 0.35 degree C [ per channel ]/W is attached to the exterior, and since a cooling effect can take greatly very much, the junction temperature of a power transistor can be used, stopping it low enough.

Since the speaker change is using the relay for protection as it is, it does not have a speaker changeover switch and is suppressing the fall of the dumping factor by the contact resistance of a switch.


Rating of a mode
Form direct-current power amplifier
Circuit system Three steps of differential amplification, the current mirrored live
Three-step Darlington parallel PP (direct-current amplifier)
Output (20Hz - 20kHz, THD 0.1%) 150W/150W (8ohms)
THD (8 ohms, 20Hz - 20kHz) 0.008% or less (1W output)
Cross modulation distortion 0.01% (70Hz : 7kHz = 4:1 or 8ohms)
0.008% or less (at the time of 8 ohms and an Output power)
Output bandwidth (IHF 0.1%, 8ohms) 10Hz - 100kHz
Input sensitivity/impedance 1V(variable) /50kohm
Frequency response (0.5W output) direct-current-150kHz+0 -1dB
Remains noise (input end short-circuit) 0.15mV or less
S/N (A network, input end short-circuit) 120dB or more
Dumping factor 100 (8 ohms, 20Hz - 20kHz) or more
Channel separation
(Input end short-circuit)
1kHz:100dB
20kHz:80dB
Conformity load impedance 4-16ohm
Power source AC100V, 50Hz/60Hz
Power consumption Output power: 550W
Dimensions Width 425x height 170x depth of 285mm
Weight 18kg
Attachment PIN-PIN cord
Two handles