LUXMAN T-4/T-4B

Commentary

FM/AM tuner that adopts CLL (Closed Loop Locked) system.

A CLL-type tuning system unique to LUX is used for tuning.
This method is based on the transmission frequency of an FM broadcasting station controlled by a crystal oscillator. It is a total control method including the front end of the tuner, the IF stage (intermediate frequency amplification stage), and the detection stage. The basic circuit of the tuner is not affected by fluctuations in external conditions such as temperature, and a stable reception state can be obtained.
This CLL tuning system has a capture range to adjust to the center frequency of the broadcasting station and a lock range to maintain a stable reception state, similar to the PLL circuit of the quartz lock system and the synthesizer system. Therefore, once the radio wave of the broadcasting station enters the capture range and is locked, a highly tuned reception state is maintained by a powerful feedback circuit.
A built-in re-lock circuit (Dynamic Kick System) eliminates the need for re-tuning when the tuner is turned off.

It is equipped with an Accu-touch mechanism in order to catch the accurate tuning point.
The Accu-Touch mechanism detects an accurate center point using the control voltage of the CLL circuit and mechanically locks the tuning knob. When the tuning knob is turned at a normal speed, the knob is locked temporarily (for approximately one second) with a sense of force.

The front-end of the FM tuner section uses a double varicon type with an emphasis on input-resistant characteristics. It uses an RF stage with excellent input-resistant characteristics using a MOS-type FET and a local oscillation circuit to obtain excellent characteristics. The AGC (Automatic Gain Control) circuit further improves input-resistant characteristics and enables clear reproduction of high-field-strength radio waves.
The IF stage is designed for low distortion, and in order to make this perfect, the detection stage is combined with NEW Cadmium Racea ICs and special detection transformers.
The MPX stage employs carefully selected PLL-ICs with high separation characteristics. In addition, a 3-pole type low-pass filter is independent on the left and right sides to improve the separation characteristics in the high-frequency range.
The audio stage is equipped with an operational amplifier IC to keep the output impedance low and suppress the high-frequency attenuation caused by the shield wire.

The IF stage of the FM tuner section can switch between two levels of bandwidth.
For wide operation, two sets of ceramic filters focusing on group delay characteristics are used to obtain low distortion rate characteristics. For narrow operation, a narrow band ceramic filter is added to obtain high selectivity characteristics.
In addition, a beat prevention circuit is installed in order to perfect the interference countermeasure at narrow time.

Equipped with FM muting level control, FM muting switch, 5-level signal strength indicator, center indicator, etc.

The T-4 comes in 2 color variations, the silver type T-4 and the black type T-4B.

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 50 Hz to 10 kHz ± 0.3 dB
Distortion factor	wide mono: 0.07%(100Hz) 0.07%(1kHz) 0.15%(6kHz) stereo: 0.15%(100Hz) 0.1%(1kHz) 0.25%(6kHz) narrow mono:0.2%(1kHz) stereo:0.5%(1kHz)
Capture ratio	wide:0.9dB narrow:1.8dB
2 signal selectivity (± 400 kHz)	wide:40dB narrow:80dB
Spurious characteristic	80dB
IF interference rejection ratio	80dB
Image ratio	55dB
Amplitude modulation suppression	60dB
Stereo separation	wide: 45dB(100Hz) 50dB(1kHz) 40dB(10kHz) narrow: 30dB(1kHz)
Carrier leak rejection ratio	65dB
Output Voltage / Impedance	1V/100 Ω
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%
Output voltage	0.3V
<General>
Accessory circuit	CLL circuit Tuning lock mechanism IF bandwidth switching Center indicator Signal strength indicator FM muting switch FM muting level control
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption (Electrical Appliance and Material Control Law)	8W
External dimensions	Width 438x Height 84x Depth 346 mm
Weight	6.5kg