Audio Database


DIATONE DA-F15/DA-F15S DA-F15: 60,000yen(around the 1978 time)
DA-F15S: 59,000yen(around the 1979 time)

FM tuner which adopted the Quartz PLL synthesizer system.

The Quartz PLL synthesizer system is adopted and local oscillation frequency is controlled by the 100kHz primitive signal which made the crystal (6.4MHz) high-precision as a vibrator 1/64 by the divide term. Thereby, for 76-90MHz could be correctly aligned and locked at intervals of 100kHz, and also the frequency system of a local oscillator has realized accuracy as high as ±3kHz (-10-+60 degrees C).
By this system, since it always locks in the frequency of a broadcasting station, as for the distorted characteristic and separation characteristic etc., the optimal value is always acquired.

The lock indicator is adopted, and the freerunning frequency of the local oscillator has shifted to which by lighting of three light emitting diodes, or it can check at a glance.

The degree of selection of IF stage is made into Narrow and the change type of Wide, and is made into 2 block configurations which became independent, respectively.
In the degree Narrow of selection, it becomes the composition of two ceramics filters [ four ], and it becomes the composition of a 4 pole +6 pole phase linear LC filter, and becomes a high selection degree tuner with quantity S/N and a low distorted tuner at Wide again.

Low distorted-ization is attained by adoption of the 4 pole +6 pole phase linear filter.
Moreover, while adopting the discrete transformer of an establishment meter, and PLL MPX IC and improving a THD, improvement in S/N, a stereo separation, and temperature stability is aimed at.

The front end part is raising stability by adoption of low dual gate and MOS FET of the noise figure selected carefully, a precision 5-unit variable condenser, a balanced mixer, etc.

The air-check oscillator (calibrator) is built in.

There were two kinds, DA-F15 which equipped the carrying handle for rack-mounted one, and DA-F 15S which has not equipped the carrying handle.


Rating of a mode
Form FM stereo tuner
Practical speed 1.8 microvolts (10.3dBf)
The degree of effective selection (±400kHz) Wide:45dB
Capture ratio Wide:0.8dB
S/N ratio (stereo) Wide:77dB
Image disturbance ratio 110dB
IF disturbance ratio 110dB
Spurious disturbance ratio 100dB
AM oppression ratio Wide:65dB
THD (stereo, 1kHz) Wide:0.08%
Stereo separation
1kHz: Wide:50dB
10kHz: Wide:35dB
Career leak oppression ratio 65dB
Frequency response 30Hz-15kHz+0.5 -1.0 dB
An Output voltage/impedance 0-500mV/5kohm
Dimensions DA-F15: Width 480x height 108x depth of 356mm
DA-F 15S: Width 424x height 108x depth of 345mm
Weight DA-F15:6.8kg