Technics SA-R40 (1981) | Aircheck Amp

 

Advertised as an "Aircheck Amp" that integrates an FM/AM tuner, cassette deck and pre-main amplifier. This features a cassette recorder with electronically controlled DC motor. Fluctuations in tape tension during recording and playback are controlled to a minimum by controlling the reel motor current with an electronic circuit. The recording / reproducing head uses an all-Sendust head with high saturation magnetic flux density and low high-frequency loss. In addition to the Sendust head with excellent abrasion resistance, a Sendust mask is used on the tape contact surface other than the core to prevent uneven wear. The head shape is a hyperbolic shape with excellent contact with the tape to prevent disturbance of frequency characteristics. The erasing head uses a 3-gap ferrite head with high erasing efficiency to cope with the high coercive force of metal tapes. It is equipped with an automatic music selection mechanism (TPS) that can search up to 9 songs. It is also equipped with an FL display that displays peak values in two colors while the peak value is clearly displayed with an attack time of 120 μ sec. and a recovery time of 270 msec. Equipped with Dolby NR circuit and recording / playback timer standby. The tuner section is equipped with a quartz synthesizer. The front-end uses a high-Q varicap and junction FET to improve the IM interference rejection capability, and the IF stage uses a ceramic filter with excellent group delay characteristics to obtain sharp selectivity characteristics. The reference frequency for locking the local oscillation frequency of the quartz synthesizer tuner is set to 25 kHz outside the audio band to prevent leakage into the audio band and improve sound quality. In addition, the synthesizer section employs a unique swallow in counter method and a special frequency division method that uses a prescaler controller to control 1/16 and 1/17 minute periods prevent spurious interference from occurring in the broadcast band. Presets for 7 FM/AM stations are available. In addition, an auto-scan tuning function is installed. If you turn on the auto-scan button and press one push of the up/down key, you can tune to the nearest station. If you turn off auto-scan, manual tuning is also available. Equipped with 5 LED signal strength indicator to indicate electric field strength. The amplifier section uses a new class A amplifier (40W/ch) that combines the quality of class A operation with the high efficiency of class B operation. In this method, a constant bias current is supplied in synchronization with the rest cycle to the output  transistor which normally goes into complete rest alternately in order to obtain high efficiency in class B and class AB by a synchronous bias circuit, and switching distortion caused by the rest is eliminated by keeping the output stage active at all times. In addition, since the signal path and bias current path are independent, the output stage always keeps an appropriate operating point. Together with the function of the high-speed response diode, crossover distortion is eliminated and the sound quality of class A operation is obtained. In addition, a new study of the NFB theory was added, and a linear feedback circuit unique to  Technics with infinite gain in the NF loop is mounted, and the strain characteristic in the range of audibility is greatly improved. It uses a unique concentrated power block that reduces degradation of high-frequency characteristics due to electromagnetic radiation. The phono equalizer is an ICL circuit without the influence of the input capacitor. It consists of an IC with a differential amplifier circuit using a low-noise FET, an input stage using a current mirror load, and an output stage using a SEPP circuit. By using the separately sold remote control box (RP-9645), the set can be operated by a remote control. External dimensions: Width 430x Height 119x Depth 394 mm | Weight 12.0kg

Powered by www.1001hifi.com