1001 Hi-Fi Info: August 2021

28 August 2021

Technics RS-B100 (1983) - The Science of Sound

The RS-B100 cassette recorder from 1983 is a deck that brings together every feature even the most demanding audiophile could desire. The Quartz DD Closed-Loop Double Capstan is an advanced tape transport system designed to maximize speed accuracy and protect tape from outside influences when it is in contact with the heads. There are two capstans, one on either side of the head block. The take-up capstan is an extension of the Technics planar opposed direct drive motor spindle. Employed for the first time in the RS-B100, the innovative Phase Compensation circuitry rectifies high range phase linearity. So you enjoy a dramatic improvement in sound quality. Playback amplifier performance is supplemented by direct coupled construction using dual FETs. Since there are no coupling capacitors in the signal path, you obtain the full benefits of Phase Compensation circuitry. The RS-B100 has all three of the world's finest noise reduction systems. Equally important, they are all in double circuits so you can enjoy 3-head real-time monitoring with correct NR decoding. dbx provides up to 110dB dynamic range while virtually eliminating noise. An added benefit is the built-in dbx disc decoder for playback of dbx encoded records (vinyl). Dolby C and B noise reduction assure complete compatibility with other decks and prerecorded cassettes. The MPX filter can be switched on to avoid NR mistracking when recording FM broadcasts.

The RS-B100 features AX (amorphous) combination 3-head system. The noble metal ruthenium (Ru), combined with carefully balanced admixtures, provides higher saturation flux density in the recording head and grater permeability in the playback head. Of course, the wider 2.5 micron recording gap width also contributes to higher MOL while the narrower 0.8 micron playback head gap extends high frequency response. The Technics combination head avoids azimuth adjustment problems since the recording and plyback head gap angles are precisely aligned in a computer controlled manufacturing process. Besides the DD capstan motor, the RS-B100 uses a second, high torque, DC motor for reel drive and one additional motor to move the head block.The RS-B100's advanced metering system uses 18 fluorescent display segments to show the signal level from -40dB to +18dB. This wide range more accurately reflects the higher recording levels possible with dbx. The RS-B100 lets you take advantage of the strong points of particular tapes for specific applications. Left and right channel recording calibration is independent and bias can be adjusted for normal and chrome tapes. As shown in the photo, the meters automatically switch to 1dB-step indication when the test signal (400Hz/12.5kHz) oscillators are used. The 3-way Digital Tape Counter can be switched to show remaining tape time, elapsed rec mute time and a highly accurate 3-digit tape counter. Other features include: music search, output level control, timer capability, black and silver input level knobs included and optional remote control (RP-9645) available. Technical data: Frequency response: Metal 15-25000Hz (20-23000Hz +/-3db), Chrome 15-23000Hz (20-21000Hz +/-3dB), Normal 15-21000Hz (20-19000Hz +/-3dB) | Dynamic range 110dB with dbx | Dimensions: 430x98x273 mm | Weight 5.6kg

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21 August 2021

Sansui SP-20000 (1973) - Precision Enginereed

Sansui has three good things (and one bad thing) to tell you about the SP-20000 three-way, floorstanding speaker system introduced in 1973. First, the bad thing: if you play bad music through it, you hear bad music from it. What could be more fair ? The SP-20000 is a full-bodied speaker system entirely without a "personality" of it's own. That's good. The sound waves it puts out are exact conversions of the electrical impulses it receives from your amplifier or receiver. Thus, good or bad, the material you feed it is reproduced accurately and objectively as the medium of high fidelity can achieve. When you hear the results you'll definitely agree that this is good thing number one. Good thing number two is the fact that two of its three active speaker drivers employ a revolutionary Sansui development called the Direct-Drive Ring Diaphragm - or DDRD for short - to improve phase response, transient response and frequency response. The tweeter and midrange units in the SP-20000 are the first commercially available speakers to use this unique system where the voice coil is the diaphragm, and vice versa. Good thing number three is that the total design of the SP-20000 is integrated right down to the most minute detail. A precision-engineered "passive radiator" woofer is included to smooth and enrich the lows. The crossover and level control system is accurate and extremely flexible. The long-excursion, free-surround woofer is capable of very flat (linear) response at all input levels with reduced intermodulation distortion. And to wrap it up, the SP-20000's sensitivity (93dB/m/W, which is high but not too high) means that inputs from the exceptionally big peak of 100 watts clear down to low-power signals are handled efficiently at any listening level.

The clean and linear musical reproduction of the SP-20000 goes for any kind of music, from bubblegum to Bartok and from jug bands to symphonies. Sansui markets the SP-20000 by the pair, the right-channel unit is a mirror-image of the left-channel unit in terms of speaker placement. Each matched pair of SP-20000 comes with a pair of two-way speaker stands of attractive and strong aluminum tubing. Speakers may be positioned flat or on a slght angle. Technical data: Woofer - 255 mm cone, Passive radiator - 255 mm cone, Midrange - 90 mm horn, Tweeter - 40 mm horn | Power rating 100 W (Max.) | Impedance 8 ohms | Sensitivity 93 dB/W | Frequency range 25 to 40,000 Hz | Crossover 1.500Hz, 7.000Hz 12dB/oct. L-C parallel type | Dimensions without stand 376 W x 786 H x 320 D mm | Weight 30 kg.

14 August 2021

PHILIPS N4520 (1979) - Truly Professional Results

King of PHILIPS tape recorders, this is the PHILIPS N4520 reel to reel tape recorder introduced to the market at the end of 1978 begining of 1979. This high quality 3 motor 3 head tape recorder was available both as a 4-track recorder (N4520) and 2 track recorder (N4522) both featuring 38, 19 and 9.5 cm/s tape speeds. The reel drives were using direct drive motors while the capstan drive was using a belt drive PLL Quartz controlled motor. A high precision digital display was used to measure tape length in meter and decimeter. The use of FSX/Ferrite heads and a continuosly variable BIAS made possible to achive high quality recordings with speeds up to 38 cm/s. There is provision for separate microphone/DIN and line level input that can be mixed together while the sound-on-sound function could be used by home musicians to record their multi-instrumental (vocal) recordings. Accurate recording levels can be achieved with the use of two needle type selectable VU/Peak level meters with Peak LED level. For fast winding there is a variable speed control while for headphone output there is a separate headphone amplifier. Technical data for N4520: Frequency response 30-26,000 Hz (38 cm/s) 30-20,000 Hz (19 cm/s) Signal to noise: 64 dB (38/19 cm/s) Dimensions: 530 W x 527 H x 230 D mm Weight: 25 kg.