Sony Super Metal Master

Sony Super Metal Master

Sony Super Metal Master - a ceramic legend among tape cassettes

Ceramic icon from analogue heaven - C-90SMMST

At the height of the cassette era, when magnetic recording was approaching its technological limits, Sony came up with a product that still commands respect today. The Sony Super Metal Master, launched in 1992, was a cassette that pushed the limits of analogue technology at the time. Whether in terms of design or recording parameters, it was a medium created without compromise.

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Ceramic body: Precision that plastic never offered

Conventional audio cassettes were made from plastic - cheap, available, but prone to warping, resonance and inaccuracy. Sony, however, took a very different approach. The Super Metal Master's case was made from two pieces of oxide ceramic, molded to tolerances matching the precision of the watchmaking industry. The body was tightly assembled with quality screws to provide absolute rigidity.

As a result, the case offered:

• Extremely low resonance,
• excellent resistance to vibration and temperature changes,
• perfect tape routing and constant contact with the heads,
• stability at high rewind speeds.

In addition, the body design required special solutions - for example, the anti-lubrication plugs were reusable, because the classic plastic ones cannot be removed from the ceramic housing.

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Innovative guide block with integrated vibration damping

When designing the Super Metal Master, Sony approached the cartridge as a complete mechanical system. A major innovation was the newly designed tape guide block, which was integrated with the shielding plate. This block was made of ceramic composite and designed to provide maximum tape guide stability even at high rewind and recording speeds.

The shielding plate also performed an anti-vibration function - its construction was designed to minimize the transmission of external vibrations to the tape mechanism and mechanical guiding. The result was effective suppression of micro-vibrations that would otherwise cause modulation distortion or instability in the signal.

Critical parts of the tape guide, such as pulleys and pressure elements, were seated in precisely machined holes in the guide block. The two halves of the cassette were designed to symmetrically and mechanically tightly encircle this element, thus achieving extreme resistance to deformation and ensuring perfectly smooth and precise tape operation.

Type IV Metal: Tape without compromise

Inside the cassette was Type IV metal tape of the highest quality. According to the information available, this was a unique multi-layer version with extremely fine metal particles and an exceptionally low coefficient of friction.

Technical parameters:

• Frequency range: 20 Hz - 25 kHz (depending on the type of recorder).
• Output level: very high, suitable for mastering
• Low noise: almost inaudible in conjunction with Dolby S

The tape has been optimised for recording on high-end machines, allowing detailed reproduction of demanding acoustic recordings and digital masters.

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SONY

We wanted to reinforce the principles of analogue recording and reproduction as much as possible. Our challenge in developing Super Metal Master was to create a sound with depth and warmth that was different from digital sound. Sony has developed many cartridges in the past, but in developing this new cartridge we had to start from scratch. For example, more than 50 different materials were selected and tested to determine the cartridge material. We then made about 500 different prototype cartridges and examined the sound balance from different angles. It took four years for the tape to mature, trying to reach the pinnacle of all cassette tapes. Super Metal Master challenged the limits of analogue technology and opened up new possibilities for cassette tapes.

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SONY - Super Metal Master five-layer tape

Achieving superior sound quality has been a relentless pursuit of technology. Flattening the tape surface reduces modulation noise, a different noise component from the original sound, and improves high frequency characteristics. However, merely flattening the tape surface leads to an increase in distortion noise because the head also reproduces the noise component without loss. Sony has succeeded in minimizing distortion noise by improving the smoothness of the tape surface and using a newly developed material with ultrafine magnetic particles. In addition, by using 'double coating' - two different types of magnetic material, one to improve output in the high frequency band and the other to improve output in the low and mid frequency bands - Sony has succeeded in achieving better output in all bands. Sony's development team also tackled another challenge, which was to further improve runout, another source of modulation noise that contributes to poor sound quality. Therefore, the Super Metal Master tapes were designed with a five-layer "multi-layer magnetics" structure. The fourth "base layer" from the top magnetic layer is a smooth UFS (Ultra Flat Surface) base. This suppresses modulation noise, which is the cause of poor sound quality.

Layers. The "glue layer in the middle" not only improves the adhesion of the layers, but more importantly plays an extremely important role in increasing the life of the tape. Sony is not proud of the number of layers, but of the depth of sound that this five-layer structure achieves.

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Listening: transparency and dynamics

The Sony TC-K970ES, a three-headed deck launched in 1993, was used to test the Sony Super Metal Master cartridge. This top-of-the-line ES (Elevated Standard) model offered:

• separate recording and reading heads,
• precision transport with two motors,
• manual bias and level calibration,
• and Dolby B/C/S support.

The result was a clear endorsement of the cartridge's quality: the sound was calm, with deep, controlled bass, plastic mids, and non-aggressive, smooth highs. Instrument separation was exceptional, and spatial information remained clear even in more complex passages.

Curiosities and technical details you may not have known

• Year of release: 1992
• Ceramic body: extreme precision and rigidity, reusable plugs against overwash
• Production of the body: according to sources, carried out at the Meißen-Triebischtal porcelain factory near Dresden
• Tape type: Metal Type IV, possible multilayer construction with high output reserve
• Price: at launch approx. 2600 yen (more than 40 USD at the time)
• Packaging: each piece had a deluxe aluminum case with printing

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A collector's jewel

Today it is a highly prized collector's item. Not only because of its design, but also because of its rarity - only a limited number were produced and the cartridge was sold mainly on the Japanese market. Used pieces in good condition now sell for 100-150 euros or more.

The Sony Super Metal Master remains the definitive pinnacle of cassette technology, an example of what can be achieved when development is not limited by budget, but only by physics and the pursuit of perfection.

The 1992 Sony Super Metal Master cassette is considered the most perfect audio cassette of all time. With its ceramic body, Type IV metallic tape and exceptional accuracy, it has become a legend and a collector's gem.