Sansui AU-X1 (1979) | Ultra-High Speed

 

Can it surpass the pinnacle of separate amplifiers? The AU-X1 super integrated amplifier was born from a straightforward approach. If you were to create the ideal amplifier, the theme would likely remain unchanged from the past and present: "Straight wire with gain is best." Without compromising the purity of the program source, for the purpose of pure amplification, Sansui believe that each part of the amplifier must be permeated with a straight idea, and so they created the AU-X1. For example, from the MC head amplifier to the power amplifier, all components are configured with full push-pull, all DC amplifiers. Furthermore, the signal path is simplified by enabling direct transmission from the equalizer amplifier to the power amplifier over the shortest possible distance, resulting in an exemplary construction for high-fidelity playback. The power amplifier section takes the dynamic characteristics of the amplifier one step further, by combining a diamond differential circuit with the newly developed linear high-speed element LAPT. Furthermore, the power supply section that supports these must naturally be strengthened. With completely separate left and right channels for all stages, the power stage, pre-drive stage, flat amplifier, equalizer, and MC head amplifier, all are powered by independent power supplies, using two transformers: a large-capacity toroidal transformer of over 600Ω and an 8601W EI transformer. The AU-X1 features a total of eight power supply systems. Combined with a gigantic 80,000m² electrolytic capacitor, this powerful power supply section remains unfazed by any peak input or continuous large input, demonstrating its effectiveness in improving the amplifier's dynamic characteristics. The AU-X1's weight of 27.7 kg is a symbol of the comprehensiveness of its power supply section. The AU-X1 approaches the ideal amplifier. We are confident in calling it "a super integrated amplifier that can comfortably drive world-renowned instruments such as the JBL4343."

Specifications:

Effective output (5 hz to 20 khz, THD 0.007%) 160W + 160W (8 Ω) 220W + 220W (4 Ω)

Total harmonic distortion factor (5 Hz to 20 kHz) 0.007% or Less (8 Ω)

Output Bandwidth (IHF, THD 0.02%): 5 Hz ~ 70 kHz (8 Ω)

Frequency Response (1W) DC ~ 500 kHz (+ 0 dB, -3dB)

Rise Time / Fall Time 0.5 μ sec

Slew rate: ± 260 V / μ sec

Total harmonic distortion factor MC (1 kHz, Rec Out) : 0.005% or less

External dimensions: Width 480x Height 195x Depth 450 mm

Weight: 27.7kg

Original sale price in Germany: 2800 DM

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PIONEER CT-720 (1979) | 3 Head System - Metal Tape

 

The CT-720 introduced in 1979 uses Pioneer's unique recording/playback combination head, which uses Sendust alloy as the core material. This improves wear resistance, distortion characteristics at high inputs, frequency response, and signal-to-noise ratio, while also providing an extremely smooth head touch. Furthermore, this Sendust alloy head is resistant to deterioration of characteristics due to the adhesion of magnetic powder or dust, or magnetization. This results in smooth frequency response (20-19,000Hz-METAL) and a high signal-to-noise ratio (over 69dB with Dolby ON), bringing out the full potential of metal tape with its wide dynamic range. The CT-720 is equipped with a high-precision two-motor mechanism, with a constant-speed drive motor for driving the capstan and a separate motor for the reel drive. For the constant-speed drive, an electronically controlled DC servo motor with a built-in generator is used. This motor detects and corrects even the slightest change in rotation speed using the frequency generated by the generator, ensuring accurate and stable rotation at all times. Furthermore, by combining a capstan that has been processed to micron-order accuracy using Pioneer's precision processing technology with a large flywheel that has excellent dynamic balance, it achieved an excellent rotational fluctuation of less than 0.04% (WRMS). The reel drive uses a DC high-torque motor with strong rotational torque and minimal ripple, enabling stable tape fast-forward and rewind operations while also providing extremely high reliability and durability. Another unique feature is the 2-color FL level meter. The level meter features a high-precision FL level meter that eliminates overshoot and undershoot even for high-level recordings. It covers a wide range of -20 to +8 dB, making it easy to handle even metal tapes capable of high-level recording. Its easy-to-read two-color display illuminates blue for levels below 0 dB and orange for levels above 0 dB. Furthermore, the FL level meter can be switched between an average meter that indicates the average value of the input signal and a peak meter that quickly indicates instantaneous pulse components. This allows for reliable level monitoring for a wide range of program sources, including music with sharp attack times like piano solos, ensuring the best performance of not only metal tapes but also various other tapes, ensuring high-quality recordings. One aspect of cassette decks that is surprisingly often overlooked is the pursuit of ease of use. The CT-720 employs a full-open loading system that allows for quicker and more reliable loading and replacement of cassette tapes, as well as checking the tape's running status and label. The head is located at the front, making cleaning and maintenance of the head and capstan easy. The tape running switching mechanism also employs an electronic direct change footbush operation button. Moreover, this operation button is extremely rational from an ergonomic standpoint. The buttons are arranged in a convenient manner, eliminating the risk of misoperation and enhancing reliability. The operation buttons can be preset, so you can link them with the timer to record voice messages and play alarms. Equipped with a monitor switch, by switching the switch to SOURCEŁTAPE you can instantly check the recording quality by ear. The bias fine adjustment knob allows you to adjust the optimum bias value, which varies slightly from tape to tape, while monitoring by ear. The 4-stage tape selector (METAL/CrO, Fe-Cr/STD) allows recording and playback to take full advantage of the characteristics of the tape being used. 

Specifications:

Recording head: Sendust head x 1

Playhead: Sendust head x 1

Erasing head: Special alloy head x 1

Constant speed drive motor: Electronically controlled DC motor (built-in generator) x 1

Fast forward/rewind motor: DC high torque motor

Wow & Flutter: 0.04% or less (WRMS)

Frequency response: 

(LH tape, -20dB recording) 20 to 17,000Hz 

(Ferrichrome tape, -20dB recording) 20 to 18,000Hz 

(Chrome tape, -20dB recording) 20 to 18,000Hz 

(Metal tape, -20dB recording) 20 to 19,000Hz 

Power supply AC100V, 50/60Hz

External dimensions: 420 (W) x 187 (H) x 368.5 (D) mm

Weight: 9.2 kg

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A&D DP-9000 (1988) | Advanced Audio

 

While utilizing advanced digital technology, A&D strives for perfection as a tool for listening to music. The DP-9000, a prestige CD player, epitomizes the philosophy behind A&D's digital audio equipment. From powerful energy to delicate, minute signals, the purity and information content of digital sources are faithfully extracted and transformed into crystal-clear, natural music. This represents a new milestone in high-purity digital sound reproduction. The first thing you'll notice about the DP-9000 is the incredibly rigid mechanism hidden within. The chassis that forms the body is a massive U-shaped structure made of die-cast aluminum, molded into a single unit, even down to the sides. Furthermore, the bottom of the chassis features a honeycomb structure for added strength. The top panel is made of 3.2mm thick copper-plated steel. The pickup mechanism, from tray to motor, is also constructed of sturdy die-cast aluminum and directly mounted to the chassis. Unwanted vibrations that corrupt the music signal are completely shut out. And of course, mutual interference between the digital and analog sections is thoroughly eliminated, from the power supply to the construction. The power supply uses separate transformers for digital and analog, with a toroidal core transformer for the analog section to ensure high sound quality. The analog circuit board is tightly shielded in a copper-plated steel case. The purity of the required performance is maximized, and unnecessary factors are thoroughly eliminated to get to the essence. You can be sure that you will be able to feel A&D's commitment to manufacturing in the purest sound quality.

The DP-9000 features optical and coaxial digital direct outputs, enabling development into a digital link system that transmits digital signals with high purity. The D/A conversion section employs a 4x oversampling, 18-bit precision, 266th-order digital filter. With carefully selected mature digital components to prioritize sound quality. The output amplifier, located at the final stage of the analog circuit, is a discrete DC amplifier equipped with a DC servo, eliminating coupling capacitors. This uncompromising approach achieves the pinnacle of potential. The components used are carefully selected for their physical characteristics and audibility, including: a vertically mounted, disc-sized stabilized clamper to suppress unwanted disc vibrations; an A-servo system with anti-shock and anti-defect features; a large, centralized display that can be turned off while remaining partially visible; and a variety of CD player-specific playback functions, including program selection, direct selection, and repeat play.

Main Specifications: Pickup: 3-beam laser pickup; Wow and flutter: Below measurable limits; Total harmonic distortion: 0.0025% or less (EIAJ); Frequency response: 2Hz-20kHz ±0.3dB; Dynamic range: 97dB or more (EIAJ); Signal-to-noise ratio: 106dB or more (EIAJ); Dimensions and weight: 460(W) x 112(H) x 330(D) mm, 13.6 kg

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