SANSUI AU-405 (1999) | Pure Non NF

 

The AU-405 from Sansui introduced in 1999, a wide-range DC amplifier, was the world's first Pure Non NF circuit amplifier for vividly reproducing next-generation, high-quality digital sources. Built to experience realistic sound reproduction close to the original recording, thanks to the astonishing specifications of the new generation of Super Audio CD and DVD Audio (frequency range DC to 100kHz, dynamic range of over 120dB). This ultra-wide-range DC amplifier is unlike anything you'd expect from a mass-market device. The Pure Non NF circuit, which uses no feedback in the output stage, achieves powerful speaker drive. To drive speakers more dynamically, the AU-405 features a newly developed Pure Non NF circuit. This circuit design ensures that the output stage is unaffected by NF (Negative Feedback), allowing for smoother current supply for speaker drive. This significantly improves current response, enabling speakers to respond more faithfully to the music signal, resulting in smoother operation and a wider operating range. The dynamic range of the sound is expanded, dramatically improving the depth, clarity, and speed of the sound. The frequency response is DC~200kHz (±0dB, -3dB), making it an ultra-wide-range DC amplifier. It reproduces sound smoothly from low to ultra-high frequencies. A DC (direct coupling) amplifier amplifies signals directly and with high density from DC to high frequencies. Its greatest feature is that it is unaffected by the sound quality caused by capacitors in the signal path, and the low-frequency time constant can be reduced. Equipped with a Pure Non NF circuit, the AU-405 maximizes the capabilities of an ultra-wide-range DC amplifier, reproducing a wide range from sub-audible low frequencies to ultra-high frequencies of digital sources. Sansui's amplifier-making expertise has also been applied to the power supply section, which can be considered the heart of the amplifier. By employing a heavy-duty power transformer with enhanced vibration damping and heat resistance through high-density filling material, and audio-specific electrolytic capacitors with excellent charge and discharge speeds, it is possible to quickly supply power to cope with the rapidly changing dynamic range of digital sources and generate a generous 80W + 80W (60) high power. A newly developed strap-mount structure controls vibrations of the power transformer. The AU-405 employs a strap-mount system to suspend the power transformer upside down from the top of the body as a vibration countermeasure. This unique structure utilizes the weight of the transformer, which is filled with high-density material, to effectively prevent the transmission of vibrations and protect sound quality. Four modes of presence control allow you to freely adjust the optimal frequency balance. "Loudness 1 & 2" boosts both high and low frequencies simultaneously, while "Bass Boost 1 & 2" only increases the low frequencies, which are often lacking in small speakers. Selected high-grade parts enable superior sound quality that surpasses its class. Sansui have carefully selected audio components, including electrolytic capacitors and resistors, without making any compromises. Furthermore, thoroughly ensured that each component is made of non-magnetic material and has excellent vibration damping performance. Specifications: Effective output (20Hz~20kHz, both channels operating simultaneously): 80W+80W(60), 60W+60W(80) | Total Harmonic Distortion (20Hz~20kHz, effective output): 0.07% or less (80) | Intermodulation Distortion (effective output, 60Hz:7kHz=4:1, SMPTE method): 0.07% or less (80) | Frequency response: PHONO (MM) 20Hz~20kHz (± 0.5dB), CD, TUNER, DVD AUDIO/LINE, MD/TAPE-1,2-DC~200kHz (+0dB, -3dB) | S/N ratio (A network, short circuit): PHONO (MC) 70dB or higher, PHONO (MM) 88dB or higher, CD, TUNER, DVD AUDIO/LINE, MD/TAPE-1,2 110dB or higher | Tone control: BASS maximum change amount ±8dB (50Hz) TREBLE maximum change amount ±8dB (10kHz) | Subsonic filter: 16Hz (-3dB), 6dB/OCT | Rated power consumption: 160W | Dimensions: 430(W) x 136(H) x 365(D) mm | Weight: 10.5 kg

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SONY TC-KA7ES (1994)

 

Released in 1994, the Sony TC-KA7ES was the flagship model of Sony's final ES Series cassette deck lineup and the company's last true high-end cassette deck. Designed as a no-compromise audiophile recorder, it combined an advanced closed-loop dual-capstan, quartz-locked direct-drive transport with a 3-phase brushless slotless (BSL) motor, oversized precision capstans, and sapphire-supported Lapis bearings to achieve exceptionally stable tape handling and an ultra-low wow and flutter figure of just 0.022%. Its three-head configuration featured Sony's renowned laser-formed amorphous recording/playback head, wound with ultra-pure 6N oxygen-free copper wire and enhanced by a pad pressure reduction mechanism that minimized tape modulation while improving contact accuracy. The carefully engineered midship drive layout isolated the transport, power supply, audio circuitry, and control sections to reduce interference, while separate recording and playback amplifier boards, a 210 kHz Super Bias system, low-impedance output stage, and premium single-crystal ESC-OCC copper wiring ensured outstanding signal purity. Mechanical construction was equally impressive, with a copper-plated FB chassis, vibration-damping eccentric insulators, dual R-core transformers housed in shielded resin cases, a rigid ceramic composite cassette holder, aluminum cassette door, Sorbothane stabilizer, and delayed-action tape clamping system all working together to suppress resonance and maintain precise tape alignment. The TC-KA7ES also featured comprehensive recording tools, including Dolby B, Dolby C, Dolby S, Dolby HX Pro, and an advanced 3-point recording calibration system for optimizing bias, sensitivity, and equalization to suit virtually any cassette formulation. A fluorescent peak level meter, linear time counter with time remain function, and the supplied RM-J701 wireless remote completed the package. Widely regarded as Sony's ultimate cassette deck, the TC-KA7ES delivered the powerful, refined sound that defined the ES Series while showcasing the company's most advanced analog recording technologies. Production ended in 2001, marking the end of Sony's high-end three-head cassette deck era. Specifications: 3-head Laser Amorphous |  Motor: Linear Torque BSL DD Motor:1 DC Motor:2 | Signal to noise: 57dB (EIAJ, Dolby NR off, metal tape) 80dB (Dolby NR S, peak level, metal tape, auditory correction) | Frequency response 15Hz–22kHz ±3dB (EIAJ, -20dB recording, metal tape) 15Hz–16kHz ±3dB (-4dB recording, metal tape) | Wow and flutter (EIAJ) ±0.04%Wpeak 0.022%WRMS | Dimensions: Width 430 x Height 135 x Depth 380 mm | Weight 12kg | Original sale price in Japan ¥120,000

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DENON DCD-1500 (1986) | Super Linear

 

The Denon DCD-1500 is a high-performance CD player engineered to deliver exceptional sound quality through a range of advanced digital and analog technologies. At its core is Denon's innovative Super Linear Converter system, which minimizes D/A conversion errors by adding a correction signal generated through an error detection and compensation circuit. This effectively eliminates the zero-cross distortion commonly associated with early CD players, resulting in smoother, more accurate audio reproduction. The DCD-1500 employs two Super Linear Converter circuits along with a dual D/A converter architecture, using independent digital filters for the left and right channels to improve channel separation, stereo imaging, and overall sonic precision.

To ensure outstanding digital performance, the player features a high-precision 2x oversampling digital filter with an ultra-flat frequency response, complemented by Denon's Computer Analyzed Linear Phase analog filter, which maintains exceptionally linear phase characteristics and flat group delay up to approximately 30 kHz. The transport mechanism is designed for stability and reliability, utilizing a newly developed three-beam optical pickup with fast-response servo circuitry for highly accurate tracking and focus control. A rigid glass fiber-reinforced BMC (Bulk Molding Compound) pickup base, a vibration-isolated floating chassis with Q-Dump construction, and a magnetic disc clamper work together to minimize the effects of vibration and resonance during playback.

The DCD-1500 also benefits from a sophisticated power supply design, with separate regulated power sources for the digital, servo, audio, and display circuits to reduce electrical interference and preserve signal purity. Its DC-coupled audio output stage with servo control further enhances sound accuracy. In addition to its audiophile-grade engineering, the player offers a comprehensive feature set including programming for up to 20 tracks, direct track access via a numeric keypad, index search, quick track selection, A-B and program repeat modes, timer playback compatibility, variable analog output, a dedicated subcode output terminal, and a supplied wireless remote control, making the Denon DCD-1500 a versatile and highly capable vintage CD player.Dimensions: 434 x 89 x 350 mm (WxHxD)

Weight: 6,0 kg | Original price in Germany approx.: 1'500 DM

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