Luxman T-12 tuner

The Accutouch system seizes the exact tuning point including that at the RF stage and offers total, stable reception even against ambient fluctuation.

In this system, the accurate center tuning point is detected by means of a control voltage at the quartz circuit, which activates a mechanical lock function. As the tuning knob is gradually turned to locate the FM station, a positive lock occurs for about 1 second at the exact tune-in point inclusive of the RF stage.

Generally speaking, a quartz-locked FM tuner has the advantage of offering very stable reception against ambient fluctuation such as temperature, etc. But this system functions to control only the local oscillator, and does not extend to the RF stage. Moreover, depending onn the method of tuning operation, tuning error is triggered at a max. 100 kHz, so that various characteristics are deteriorated (such as distortion, separation, rejection etc.) in other words, only our "Accutouch" makes it possible to make the most of the quartz lock system to prevent possible tuning error. When the power is turned off with the Quartz Lock on, the proper receiving condition is automatically obtained the next time power is turned on.

IF Bandwidth Selector

If the IF stage a 2-step bandwidth selectoris provided. In the "wide" position, 2 pairs of LC block filter are combined providing exceptionally good phase characteristics, and realizing ultra low distortion. Conversely in the "narrow" position a combination of block and ceramic ffilters achieves high selectivity.

The IF filters adopted here have excellent group-delay characteristics, however, to make the ultra low distortion tuner perfect, even small deviation of the components used should be controlled. Therefore to solve this, a phase compensation circuit is provided in the IF stage, and the units are checked one by one to realize excellent distortion characteristics.

Sonic Excellence

In the front end an exclusive FM 5-gang variable capacitor is used to make the most of the various superb characteristics in the IF  and following stages. Also high selectivity in each RF amp circuit ensures satisfactory interference rejection. In the detector circuit, a new quadrature IC and a special detector transformer are adopted to realize a low-distortion characteristic through wide bandwidth and high Signal-to-Noise ratio. Distortion at the detector stage has been suppressed down to a level below that of most test equipment. Thus no more than 0,02% distortion is realized for a deviation of ±50 kHz, or no more than 0,05% even through ±100 kHz.

A pilot signal cancellor circuit is arranged in the multiplex stage to improve frequency response and phase characteristics.

Specifications

Receiving Frequency:  87,5 MHz - 108 MHz

50 dB Quieting Sensitivity:

50 µS :  16,0 dBf 93,3 µV)

75 µS :  14,2 dBf (2,8 µV)

IHF Usable Sensitivity:  10,7 dBf (1,8 µV)

Signal-to-Noise Ratio:  80 dB

Frequency Response:  20 Hz - 17,000 Hz (within -0,5 dB, mono & stereo)

Total Harmonic Distortion:

100 Hz (wide) :  0,05% (mono); 0,07% (Stereo)

1 kHz (wide) :  0,05% (mono); 0,06% (stsreo)

6 kHz (wide) :  0,07% (mono); 0,1% 9stereo)

1 kHz (narrow) :  0,2% (mono); 0,5% (stereo)

Capture Ratio:

Wide :  0,8 dB

Narrow :  2 dB

Adjacent Channel Selectivity:  12 dB (narrow ±200 kHz)

Alternate Channel Selectivity: 

60 dB (narrow, ±300 kHz)

90db (narrow ±400 kHz)

30 dB (wide, ±400 kHz)

Spurious Response ratio:  100 dB

IF response Ratio:  100 dB

Image Response ratio:  100 dB

AM Suppression Ratio:  62 dB

Stereo Separation:

100 Hz (wide) :  45 dB

1 kHz (wide) :  50 dB

10 Hz (wide) :  45 dB

1 kHz (narrow) :  30 dB

Output Voltage:  1 V (fix);  0 V - 1 V (variable)

Output Impedance:  100 Ω (fix); 100 Ω - 1,25 k Ω (variable)

Muting Threshold:  10 µV - 500 µV (variable)

Power Consumption:  20 W

Dimensions (W x H x D):  438 x 322 x 78 mm (17-1/4" x 12-11/16" x 3-1/16")

Weight:  7 kg (15,4 lbs) net