Audio Database

T-50A
Commentary

An AM/FM stereo tuner that thoroughly pursues the basic performance of a tuner and incorporates a tuning circuit to maximize the performance.

The CLL-type tuning system (Closed Loop Locked System) is adopted.
This is a tuning system that locks the front end, IF stage (intermediate frequency amplification stage), and detection stage to the transmission frequency of the FM station, ensuring stable reception performance.
The CLL circuit also has a built-in re-lock circuit (Dynamic Kick System) so that you don't have to re-tune the tuner when you turn off the power.

To achieve more accurate tuning, it is equipped with an Accu-Touch mechanism.
The control voltage of the CLL circuit is used to detect an accurate center point and to mechanically lock the tuning knob. When the tuning knob is turned at the normal speed, the knob is temporarily locked (for approximately one second) as well as the response.

The front end uses a MOS FET for the RF stage (high-frequency amplification stage), and by adopting a low-distortion local oscillator circuit, excellent interference rejection characteristics and current modulation characteristics are obtained.
In addition, the IF stage is equipped with a two stage switching of bandwidth to achieve both low distortion rate characteristics and high selectivity characteristics. In addition, a beat prevention circuit is added to strengthen measures against interference during narrow operation.
The detector stage uses NEW Racea ICs that provide broadband and low-distortion characteristics, and the stereo demodulation stage uses PLL ICs that provide separation characteristics.

The AM tuner section emphasizes input resistance to strong electric fields. In addition, the IF stage is equipped with a ceramic filter with high selectivity.

It is equipped with an FM muting level control which can freely set the electric field strength applied to muting, a signal strength indicator which displays the signal strength in 5 stages, and a center indicator which displays whether the FM station is accurately captured.

Model Rating
Type AM/FM stereo tuner
FM Tuner Section
Practical sensitivity of IHF 1.8 μ V/10.3 dBf
50 dB quieting sensitivity 3.3 μ V/15.6 dBf
Signal-to-noise ratio 75dB
Frequency characteristic 30 Hz to 15 kHz ± 0.5 dB
Distortion factor (wide, 1 kHz) mono:0.07%
stereo:0.1%
Capture ratio wide:0.9dB
narrow:1.8dB
2 signal selectivity (± 400 kHz) wide:40dB
narrow:80dB
Spurious characteristic 80dB
Image ratio 55dB
Amplitude modulation suppression 60dB
Stereo Separation (wide) 100Hz:45dB
1kHz:50dB
Muting threshold 10 μ V ~ 300 μ V
<AM Tuner Section>
Practical sensitivity of IHF 250 μ V/m
Image ratio 50dB
IF interference rejection ratio 40dB
Signal-to-noise ratio 50dB
Distortion factor 0.6%
<General>
Output voltage FM : 1V/100 Ω
AM:0.3V
Accessory circuit CLL circuit
Tuning lock mechanism
IF bandwidth switching
Center indicator
FM muting switch
FM muting level control
Power supply voltage 100 VAC, 50Hz/60Hz
Power consumption 8W
External dimensions Width 466x Height 120x Depth 350 mm
Weight 7kg