Name: ST-70
Brand: Ortofon
SKU: 5705796310054
Price: 1599.0 EUR
Availability: InStock

Presentation of the Ortofon ST-70 Transformer for Turntables

The Ortofon ST-70 transformer is a high-end accessory designed for music enthusiasts who want to get the best out of their turntables equipped with moving coil (MC) cartridges. This device plays a crucial role in the sound reproduction chain by amplifying the very low-level signal generated by MC cartridges, while preserving great purity and optimal transparency.

Technical Specifications

A Thoughtful Design for Optimal Performance

At the heart of the ST-70 are high-quality transformers manufactured by Lundahl, a reference in the field. These transformers are surrounded by a special mu-metal shielding that effectively protects them from internal and external interference. This combination ensures precise and detailed reproduction of every note, without any sound coloration.

The ST-70 adopts a dual mono design, with separate circuits for each channel. This architecture eliminates the risks of crosstalk and distortion, resulting in a wider and more realistic stereo image, regardless of the type of music being listened to.

Robust Construction and Quality Components

To minimize losses and optimize signal transfer, the ST-70 uses a high-quality industrial printed circuit board. Gold-plated RCA connectors with Teflon insulation ensure optimal conductivity, even with high-end cables. Inside, the wiring has been reduced to the bare minimum to preserve the absolute integrity of the signal.

The ST-70 is compatible with most MC cartridges thanks to internal jumpers that allow selection between two gain and impedance options. This flexibility allows audiophiles to finely tune the transformer to their cartridge, while maintaining a sleek design.

Operating Principle

The Key Role of the Transformer

MC cartridges generate a very low amplitude signal, on the order of a few hundred microvolts. To fully exploit this signal, it must be significantly amplified, either using a dedicated MC phono preamplifier or by using a step-up transformer like the ST-70.

Although both solutions fulfill the same function, they fundamentally differ in their mode of operation and sound characteristics. Transformers are considered superior because they are entirely passive and offer exceptional performance in terms of noise and sound quality.

Crucial Impedance Matching

For optimal operation, a transformer must present an impedance matched to that of the MC cartridge used. Poor matching can degrade performance, particularly frequency response.

The ST-70 is designed to ideally match Ortofon’s Cadenza series MC cartridges, but it is also compatible with many other cartridges on the market. Its internal jumpers allow for the selection of two impedance and gain values, offering great versatility.

Advantages Over an Active Preamplifier

More Natural and Transparent Amplification

Unlike an active phono preamplifier that uses electronic components to amplify the signal, a transformer like the ST-70 is a purely passive device. It only raises the signal voltage without adding noise or coloration.

This minimalist approach results in a more natural and transparent sound, closer to what is etched in the record groove. Micro-information and the most subtle details are reproduced with great finesse, for a more immersive and realistic listening experience.

A Better Signal-to-Noise Ratio

One of the main challenges when amplifying very low-level signals from MC cartridges is maintaining a high signal-to-noise ratio. Any noise generated at this stage will be amplified along with the musical signal, thus degrading the overall sound quality.

Thanks to its fully passive design and high-quality transformers, the ST-70 manages to amplify the signal without adding significant noise. The result is an exceptional background silence that highlights the finest nuances of the music.

A Suitable MC Cartridge Choice

To fully enjoy the qualities of the ST-70, it is essential to pair it with a good-level MC cartridge capable of taking advantage of its transparency and dynamics. The Ortofon Cadenza series models are a particularly wise choice, but many other high-end cartridges on the market can also deliver excellent results.

It is important to properly adjust the load impedance of the ST-70 according to the specifications of the cartridge used, using the internal jumpers provided for this purpose. Incorrect settings can alter the frequency response and overall sound rendering.