Audio Database

The

DIATONE DA-F750
69,800yen(around the 1975 time)

Description
 
Three flat delay characteristics 6 pole phase straight line type filters are adopted as IF stage over a 400kHz zone, and it is driving to it with eight steps of differential amplifier.
While being able to expect the engine performance exceeding a linear phase ceramics filter by this and obtaining the low distortion near audio amplifier, many characteristics important for the improvement in sound quality of tuners, such as a stereo separation, are improved.
Moreover, the newly developed low noise transistor and the low-voltage circuit without Rippl were adopted, and it is measured whether it is low noise.

It uses for RF stage and a mixer stage, and the low noise dual gate MOS FET is set to 14V, and impressed electromotive force is also considering it as the design strong also against a strong electric field.
Interference exclusion capability, such as a spurious response and the inter-modulation disturbance (three signals) characteristic, is also improving sharply with the large linear range of FET, and the degree of high selection of RF magnification stage.

IC of a PLL recovery system is adopted as a multi-circuit.

3 pole Chebychev type career leak filter adoption.


Rating of a mode
Form FM/AM tuner
<FM tuner part>
Antenna A 300-ohm balance, 75-ohm disequilibrium
Practical speed 1.6 microvolts (IHF)
The degree of effective selection 70dB(IHF)
Capture ratio 1.0dB
Image disturbance ratio 90dB
IF disturbance ratio 100dB
Spurious disturbance ratio 100dB
S/N mono:75dB
stereo:70dB
AM oppression ratio 55dB
THD (100% abnormal conditions) mono:0.08%
stereo:0.1%
Separation 45dB(1kHz)
40dB(10kHz)
Muting Two-step change
MPX noise filter Two-step change
<AM tuner part>
Antenna Ferrite bar antenna
Practical speed (IHF, bar antenna) 50dB/m
The degree of selection 30dB (±10kHz)
Image disturbance ratio 70dB
S/N 55dB
<Synthesis>
Output FIXED:150mV
VARIABLE: 0-700mV
Power source AC100V 50Hz/60Hz
Power consumption 14W
Dimensions Width 425x height 148x depth of 386mm
Weight 8.5kg