SANSUI MH9 (1999) | Micro High-End Hi-Fi System

Imagine a complete micro Hi-Fi audio system that takes up barely more space than a CD case. The SANSUI MH9 micro Hi-Fi component system combines CD playback, MiniDisc recording, radio reception and compact bookshelf speakers in an elegant, space-saving design. With its platinum-gold aluminum front panels, sophisticated editing functions and optional cassette deck, the MH9 brings serious versatility to the world of miniature Hi-Fi.

SANSUI MH9 – Main Specifications

CD receiver: CD-9MH, with integrated amplifier, CD player and FM/AM tuner

MiniDisc deck: MD-9MH, featuring recording, playback and editing functions

Speakers: S-9MH, two-way bass-reflex bookshelf design

Optional cassette deck: D-9MH, featuring auto-reverse and Dolby B noise reduction

Optional rack: GX-9MH, designed specifically for the MH9 system

Amplifier output: 20W + 20W at 4 ohms (EIAJ practical maximum)

Speaker configuration: Two 10cm cone woofers and one 5cm cone tweeter per speaker

Speaker enclosure: All-wood cabinet with bass-reflex loading

Maximum speaker input: 30W (EIAJ)

Dimensions and weight:

CD receiver CD-9MH: 140 × 129 × 274mm; approximately 2.0kg

MD deck MD-9MH: 140 × 129 × 259mm; approximately 3.2kg

Each S-9MH speaker: 155 × 258 × 237mm; approximately 2.8kg

The optional D-9MH cassette deck measures 140 × 129 × 259mm and weighs approximately 2.0kg. 

The GX-9MH dedicated rack measures up to 340 × 174 × 222mm and weighs approximately 1.5kg.

The Technology Behind the SANSUI MH9. CD-9MH: CD Playback, Amplification and Radio in One Unit. Integrated functionality: The CD-9MH is the heart of the MH9 system, combining a CD player, stereo amplifier and FM/AM tuner in a remarkably compact enclosure. Its amplifier delivers a practical maximum output of 20 watts per channel into 4-ohm speakers. A Super Bass function adds extra low-frequency emphasis, while electronically controlled tone adjustment allows the sound to be tailored using the supplied wireless remote control. Digital playback: The CD player employs a 1-bit D/A converter and offers a comprehensive selection of playback modes. Its 15-track music calendar provides a quick overview of the disc, while programming allows up to 20 tracks to be selected in a preferred sequence. Repeat playback is available for a single track, the entire disc or a programmed selection. Random playback adds another way to enjoy a familiar CD collection. Radio reception: The integrated wideband FM/AM tuner covers a broad range of frequencies. An area guide function simplifies station selection, while both automatic and manual tuning are provided. The tuner also supports manual preset memory, allowing up to 15 FM stations and 15 AM stations to be stored. MD-9MH: A Fully Featured MiniDisc Recording and Editing Deck. Beyond simple recording: The MD-9MH transforms the MH9 from a compact playback system into a capable digital recording station. It supports CD-synchronized recording, making it possible to record music from a compatible CD source with minimal intervention. The deck also provides a 20-track music calendar, 20-track program selection, repeat modes and random playback. MiniDisc editing: One of MiniDisc's greatest advantages was the ability to manipulate recorded material without physically cutting tape. S-9MH: Wooden Speakers with a Double-Drive Bass System. Each cabinet contains two 10cm cone woofers for low-frequency reproduction and a 5cm cone tweeter for high frequencies. The two woofers employ a double-drive system intended to reinforce bass performance within the limitations of a small enclosure. Bass-reflex loading: The speakers use a bass-reflex design to extend low-frequency output beyond what a sealed enclosure of similar size might achieve. 

Their all-wood cabinets provide a more traditional speaker construction than the plastic enclosures often associated with compact mini systems. The result is a bookshelf design intended to complement the MH9's miniature electronics without sacrificing the character of a conventional Hi-Fi setup. D-9MH: Optional Auto-Reverse Cassette Playback and Recording. The cassette deck features auto-reverse operation, Dolby B noise reduction and synchronized recording with compatible CD and MiniDisc sources. It is important to note that the D-9MH was sold separately. It is not part of the standard three-component MH9 configuration, and the system's alarm/recording timer cannot be used to make timer recordings on this cassette deck. Elegant Styling and Everyday Convenience. Platinum-gold finish: The MH9's aluminum front panels give the system a distinctive appearance, setting it apart from more conventional black or silver mini systems. The backlit display adds visual clarity, while the supplied wireless remote control makes it easier to manage playback, tuning and electronic tone adjustments from a listening position. Alarm and recording timer: Another useful feature is the programmable timer, which allows users to set start and end times, select a source and specify the volume level. Depending on the selected source and operating mode, this provides convenient scheduled playback or recording. Last but not least this micro Hi-Fi is actually a rebranded Victor UX-MD1...

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Victor original

Sansui AU-α907MR (1995)

The Sansui AU-α907MR was a remarkable example of Japanese high-end amplifier engineering, combining substantial power reserves with sophisticated balanced circuitry and an obsessive attention to mechanical construction. At its heart lies Sansui’s New Hyper α-X balanced circuit, supported by a massive power supply, reinforced twin-mono architecture, and an elaborate system designed to control unwanted vibrations. With 160 watts per channel into 8 ohms, compatibility with both MM and MC phono cartridges, and an exceptionally wide specified frequency response, the AU-α907MR was engineered for audiophiles who demand more than raw power alone.

Sansui AU-α907MR: Main Specifications

Rated output power: 160 W + 160 W into 8 Ω

Rated output power: 190 W + 190 W into 6 Ω

Dynamic power: 580 W (2 Ω), 390 W (4 Ω), 310 W (6 Ω)

Total harmonic distortion: 0.003% or less (8 Ω)

Intermodulation distortion: 0.003% or less (8 Ω)

Damping factor: 150 (8 Ω)

Frequency response: DC–300 kHz (+0, −3 dB)

Signal-to-noise ratio: 120 dB or higher (A-weighted)

Dimensions (W × H × D): 471 × 163 × 452 mm

Weight: 33.0 kg

Rather than relying on a single design feature, Sansui combined specialized constant-current circuits, a sophisticated differential driver stage, and a carefully isolated power supply. High common-mode noise rejection is one of the principal objectives of the New Hyper α-X design. The circuit uses an advanced Wilson current mirror-type symmetrical balanced constant-current arrangement, building on Sansui’s earlier high-CMRR approach. The underlying circuit is described as achieving a theoretical CMRR improvement of 140 dB. CMRR, or common-mode rejection ratio, measures how effectively a circuit rejects unwanted signals common to both inputs. Greater operating stability is pursued through separate-winding closed-loop arrangements for the driver stage and the main output-stage power supply. These help correct current variations associated with DC offset and asymmetry between circuit components. The result is an architecture intended to maintain a more stable operating environment throughout the amplifier, from the input circuitry to the power output stage. New Diamond Differential Circuit. Fast transient response is another important part of Sansui’s design philosophy. The driver stage employs a New Diamond differential circuit that can generate a negative output without phase inversion. This arrangement is intended to provide the current needed to respond rapidly to changing input signals, helping the amplifier handle demanding musical transients. The design also incorporates cascaded first-stage FETs and a symmetrical, balanced driver power supply. These features are intended to improve operating speed, widen the circuit’s effective operating range, and reduce the potential for performance degradation when connecting equipment with different impedances. New α-X Balanced Power Supply. Stable high-current delivery is essential for an amplifier designed to drive demanding loudspeakers. The AU-α907MR addresses this with Sansui’s New α-X balanced power supply. The output stage uses a balanced closed-loop configuration, while the driver stage has a symmetrical balanced constant-current supply. These arrangements are isolated from ground to reduce the unwanted influence of unbalanced supply currents. A massive 13 kg power transformer is at the center of the design. Its quadruple-layer shield incorporates high-density filler material intended to suppress vibration during operation.

Carefully selected original-design electrolytic capacitors and fast-recovery diodes complete a power-supply section engineered for stable current delivery under demanding conditions. Reinforced Twin-Mono Construction and Vibration Control. Mechanical stability is part of the design, not simply a consequence of the amplifier’s substantial weight. Inside the Sansui AU-α907MR, the placement of the power supply, output devices, and supporting structures has been carefully considered to minimize unwanted vibration and interference. Separate left and right channel sections are a defining element of the reinforced twin-mono construction. The large power-supply components, including the transformer and electrolytic capacitors, are positioned centrally. The power units, including the power transistors and heat sinks, are arranged symmetrically on either side of the chassis and separated from the power board. This layout is intended to reduce interaction between the channels, improve weight distribution, and control the chassis’s natural vibrations. Vibration isolation throughout the chassis is achieved using a proprietary mechanical feedback system developed by Sansui. Pure-copper isolation components are fitted at critical locations, including between the master volume control and chassis, between the power transistors and heat sinks, and around the mounting bases of the electrolytic capacitors. Sansui also uses Teflon tape and sheets between selected insulators, the bottom plate, heat sinks, bonnet, and chassis. These measures are designed to limit mechanical vibration transfer between components and the enclosure. Premium Speaker Terminals and Controls. High-quality speaker connections are provided by 24-karat hardened gold-plated OFC alloy terminals from the German company WB. They are designed for low signal loss and support bi-wiring connections. Pure-copper elliptical insulators contribute to the vibration-control system, while the volume knob is machined from solid aluminum. These details reflect Sansui’s emphasis on construction quality, mechanical isolation, and carefully selected materials. Vinyl enthusiasts are also well catered for. The integrated phono equalizer supports both moving-magnet (MM) and moving-coil (MC) cartridges, with separate input sensitivity and impedance specifications for each type. This makes the Sansui a versatile centerpiece for a system combining a turntable, CD player, tuner, and tape equipment.

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SANSUI CD-α 917 XR (1994) | Reference CD Player

A Reference CD Player Built with Audiophile Precision. The SANSUI CD-α 917 XR is a high-end CD player designed to demonstrate how far digital audio engineering could go when precision, circuit isolation, and mechanical stability were treated as priorities. Featuring a then newly developed 18-bit MASH D/A conversion system, extensive vibration-control measures, and separate power supplies for digital and analog circuits, this impressive machine reflects SANSUI’s ambitious approach to reference-class CD reproduction.

SANSUI CD-α 917 XR – Main Specifications

D/A Converter: 18-bit resolution MASH converter, 2 units

Frequency Response: DC–20 kHz (±0.3 dB)

Total Harmonic Distortion: 0.0022% at 1 kHz

Signal-to-Noise Ratio: 110 dB or more (EIAJ)

Dynamic Range: 98 dB or more (EIAJ)

Wow and Flutter: Below the measurement limit

Output Voltage: 2 V (unbalanced and balanced)

Digital Outputs: Optical and coaxial, with an ON/OFF switch

Digital Attenuator: Adjustable from 0 dB to −26 dB, with fade-in and fade-out

Dimensions (W × H × D): 466 × 126 × 391 mm

Weight: 14.1 kg

Accessories: Wireless remote control

SANSUI focused on improving digital signal-reading accuracy while reducing common-mode noise and distortion. The design was intended to improve the signal-to-noise ratio, particularly addressing distortion in the high-frequency range. The conversion method also aimed to eliminate zero-crossing and nonlinear distortion in principle, helping preserve low-level musical information and subtle details. Balanced signal processing: The digital signal is processed through balanced operations, eliminating the need for an inverting amplifier in the described signal path. This helps avoid associated phase shifts and reduces the susceptibility of balanced output to noise. Completely Separated Digital and Analog Power Supplies. Independent power delivery: Rather than relying on a single shared supply, SANSUI equipped the player with dedicated transformers for the digital and analog sections. The design incorporates 15 independent power-supply systems serving individual sections, including the microcomputer, DAC, disc drive, display, and analog circuitry. This separation was intended to prevent electrical interference between circuits and reduce the risk of digital activity affecting sensitive analog audio signals. Carefully selected capacitors: The power supply also uses electrolytic capacitors featuring low-magnification aluminum foil, reflecting the manufacturer's attention to component selection and circuit performance. Copper Shielding and Mechanical Stability. A central copper dome: The CD-α 917 XR retains a center-mounted mechanical layout, enhanced by a newly developed pure-copper dome. This structure shields the central drive mechanism from surrounding circuitry. The arrangement also helps optimize weight distribution and increase chassis rigidity, while reducing motor-induced vibration and resonance. The copper shielding serves additional purposes, including limiting interference from the digital pickup section and shielding other circuitry from unwanted radiation. A resonance-controlled chassis: SANSUI paid considerable attention to the player's enclosure. The bonnet is coated with a special paint mixed with copper powder to help suppress resonance within the cabinet. Elliptical insulators help isolate the player from external vibration, while Teflon sheets and tapes are used at selected contact points. Copper plating on the back panel and center channel provides further measures against unwanted casing vibration. These details illustrate an engineering philosophy in which mechanical construction was considered an important part of achieving consistent CD playback. Premium Components Throughout the Circuitry. Audiophile-grade component selection: The CD-α 917 XR uses a range of carefully selected components, including Silmic Super Gold capacitors, GSG film capacitors with gold-plated leads, RMG resistors, SA film capacitors, and specialized styrol capacitors. Gold-plated leads and anti-vibration treatments reinforce the emphasis on component quality and mechanical stability. The CD mechanism also receives special attention, with copper plating on the play chassis and a Teflon coating among its vibration-control measures. Balanced Servo and Low-Pass Filter Design. Balanced circuitry: The player incorporates a balanced servo system and a balanced low-pass filter, complementing its balanced analog outputs. For enthusiasts using compatible equipment, balanced connections offer an alternative to conventional unbalanced RCA connections and may be particularly useful in systems where noise rejection is important. Digital Attenuation and Direct Power-Amplifier Connection. Volume control without a conventional preamplifier: One particularly useful feature is the digital attenuator, which allows the output level to be reduced from 0 dB to −26 dB. This makes it possible to connect the player directly to a compatible power amplifier, potentially simplifying the system by eliminating a separate preamplifier. The CD-α 917 XR also offers fade-in and fade-out functions, allowing the music to move smoothly from the selected listening level to silence. Beyond its core playback functions, the player includes a generous selection of features: Peak Search: Locates a disc's peak level, displays its level, and plays the selected peak passage for five seconds. Display ON/OFF: Allows the front-panel display to be switched off. Auto Space and Auto Pause: Provides additional control over pauses and gaps between tracks. Following Memory: Supports continued programming or playback memory functionality. Music Scan: Makes it easier to preview tracks. Five-Way Repeat: Offers several repeat-playback options. Wireless Remote Control: Enables convenient operation from the listening position.

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