Sansui TU-919 tuner

Sansui Patented Digitally Quartz-Locked FM/AM Stereo Tuner with Impeccable Drift-Free Tuning Accuracy.

FM Fronted Sensitivity; Enhanced by low-noise Dual-Gate MOS FET and 5-gang Tuning capacitor

The extraordinary tonal quality of the Sansui TU-919 begins here. Crossmodulation and interference are avoided in the FM fronted using a low-noise Dual-Gate MOS FET RF amp and a wide-gap, frequency-linear 5-Gang variable capacitor of high precision. The 50 dB Quieting Sensitivity is an excellent 13,5 dBf (mono) and 35,5 dBf (stereo)

 

FM IF Selectivity; Very low group delay means much-improved sound.

Tonal quality is further enhanced by flattening transient group delay and phase distortion to achieve higher selectivity with lower distortion in the FM IF section. The real test of our IF circuitry comes when inputs from your antenna vary unpredictably in level.

Actual field tests show the effectiveness of the ten differential IF stages, contained in one Darlington-connected differential IC, and the linear-phase ceramic filters found here. Changes in signal level have hardly any effect on selectivity.

 

Patented Variable Group-Delay Equalizer; Distortion is further reduced

This is a unique device that permits the independent adjustment of the equivalent amount of Frequency Response of the IF signal within the bandwidth. This, in turn, helps eliminate any deviation, however minute, in group-deley response within the bandwidth. Higher Signal-to-Noise Ratio and lower distortion are also achieved.

 

FM Stereo Sound; Wider separation and purer fidelity from PLL

Stereo FM broadcasts are multiplexed with a "pilot" signal to trigger receiving tuners into the stereo mode and enable them to "decpde" the composite signal into left and right channels.  Once its job is done, that "pilot" (a 19 kHz signal) must be entirely removed from the audio signal. The conventional filter used for this can cause more problems than it prevents.

Such 19 kHz filters are usually positioned at the output of the stereo demodulator. Together with the "pilot" they also often filter out the upper end of the frequency response and cause phase distortion as well. Sansui avoids such filters in the TU-010 for a more musical sound.

Our stereo dempdulator is a PLL type with a special "pilot" cancelling circuit (not a filter) included in its IC. It eliminates the 19 kHz signal before it enters the switching or demodulation stage. Output of the demodulator amp is pure audio.

 

Wide-Range DC Configuration; More guarantees of cleaner sound.

As in the highly advanced Sansui AU amplifiers and our best Pure Power receivers, the DC amplifier configuration in the TU-919 offers cleaner audio reproduction in both AM and FM. Main advantages are; Wider dynamic range; Lower TIM distortion; and Superb frequency response all are vital to hi-fi. These parameters are made still more dependable by our reduction of the internal power-supply impedance across the widest possible frequency range. Reproduction is always well balanced.

 

Power Supply: Attention given to better sound localization

An error-correction/amplification constant-voltage circuit of an entirely new type is found in the power supply of the TU-919. it provides unfailing power regulation for constantly high performance quality. With impedance low throughout, musical textures remain crystal clear and sound-image localization in the reproduced sound field is the sharpest possible.

 

High-Power Drive Ratio Detectr; S/N and linearity are improved

A newly-developed, wide-range, high-power drive ratio detector, driven by a triple-base Darlington-connected IC, is used in the FM discriminator. It contributes to improved linearity and Signal-to-Noise Ratio. For more stability and still less noise we've housed the discriminator in a shielded casing, separate from the IF circuit.

 

Selectable IF Band for AM; Wide/Narrow improves reception

By broadening the signal-passing bandwidth in the AM tuner section, frequency range is dramatically improved. For this reason, you'll want to use the Wide position on the IF bandwidth selector. When the station to which you have tuned is strong enough, the results in improved high frequency response are impressive. On the other hand, weak or distant AM stations are received more clearly when you use the Narrow position; the interference caused by stronger station broadcasting on adjacent frequencies is dramatically lowered.

 

Sansui Exclusive FM Digitally Quartz-Locked System; Contained in a single LSI

We've combined a quartz crystal, providing a rock-steady reference base, with an error-free digital control in the TU919. this Sansui-exclusive system detects any tuning error caused by temperature, voltage and humidity changes and compensates for it instantly. Drift is now a thing of the past. Most other quartz tuners use analog phase reference controls that compare phase of two frequencies between the local oscillators and quartz crystals. In order to check and correct errors (drift). But our TU-919 doesn't instead it has a digital control system.

With it the frequency counter samples the local oscillator's frequency constantly, once every 0,01 seconds, timed by the accurate quartz. When there's an error, it's converted to digital units, which are then converted to voltage to control the local oscillator. When there's no error, the tuned frequency is locked to the station's frequency.

Sansui's digital processing doesn't use the kind of reference signal containing infinite harmonics; therefore, we've eliminated drift without compromising spurious response ratio, Signal-to-Noise Ratio sensitivity or other important specifications.

There more features make the Sansui system still easier to use. One, you need not remove your hand from the knob to make sure the station is surely quartz-locked. Two, locking range is wide, even rough tuning locks in the desired station and keeps it locked for hours. Three, should you turn off the tuner a built-in Re-Lock system memorizes your station for instant recall when you switch it on again.

Sansui has received patents on our Quartz/Digital-Lock System. And to ensure long-term reliability of its operation we've packaged it all in a single LSI with circuits equivalent to thousands of discrete transistors, resistors and diodes.

 

Specifications

FM Section

Tuning Range:  88 to 108 MHz

50 dB Quieting Sensitivity

Mono :  12,5 dBf

Stereo :  34,0 dBf

Sensitivity

Mono :  9,0 dBf (IHF), 0,95 µV (DIN)

Stereo :  15 dBf

Signal-to-Noise Ratio

Mono :  83 dB at 80 dBf (82 dB at 65 dBf)

Stereo :  80 dB at 80 dBf (76 dB at 65 dBf)

Frequency Response

Mono :  30 to 15,000 Hz +0,2 dB -0,5 dB

Stereo :  30 to 15,000 Hz +0,2 dB -0,5 dB

Total Harmonic Distortion

Mono :  less than 0,06% at 100 Hz (0,04% at 1,000 Hz)

Stereo : less than 0,09% at 100 Hz (0,06% at 1,000 Hz)

Captire Ratio:  0,9 dB

Adjacent Channel Selectivity

Wide :  5 dB at 200 kHz

Narrow :  18 dB at 200 kHz

Alternate Channel Selectivity

Wide :  50 dB at 400 kHz

Narrow ;  80 dB at 400 kHz

Spurious Response Ratio:  110 dB at 98 MHz

Image Response Ratio:  110 dB at 98 MHz

RF Intermodulation:  75 dB at 08 MHz

AM Suppression Ratio:  60 dB at 98 MHz

Stereo Separation

40 dB at 100 Hz

50 dB at 1,000 Hz

35 dB at 10,000 Hz

30 dB from 30 to 15,000 Hz

Antenna Input Impedance

Balanced :  300 Ω 

Unbalanced ;  75 Ω

Output Voltage/Impedance

Variable :  1 V/2,5 k Ω

Dolby FM :  200 mV/9 k Ω

AM Section

Tuning Range:  530 to 1600 kHz

Sensitivity: 47 dB/m at 1,000 kHz (220 µV/m)

Selectivity:  35 dB at 1,000 kHz

Signal-to-Noise Ratio :  50 dB

T.H.D.  Less than 0,35% at 30% Mod. 80 dB/m

Image Response Ratio:  70 dB at 1,000 kHz

IF Response Ratio:  70 dB at 1,000 kHz

General

AC Outlets:  Unswitched, total 100 watts

Power Requirements:  100, 120, 220, 240  V 50/60 Hz

Power Consumption:  22 watts

Semiconductors:  73 Transistors; 57 Diodes; 6 FETs; 16 ICs

Dimensions (W x H x D):  430 x 168 x 402 mm (16-15/16" x 6-5/8" x 16-1/2")

Weight: 9,6 kg (21,2 lbs)