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Sonus Formula IV

Uni-Pivot Laboratory Standard Tonearm

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Sonus Formula IV


The Sonus Formula IV tone arm is the product of extensive research over a period of years, the need for such an item of audio equipment becoming increasingly evident with the significant advances in technology by the manufacturers of quality pickups which make special demands on tonearm parameters.

Of particular significance in this design area are such factors as effective mass of arm and cartridge in combination (as related to stylus compliance), the bias compensation demand and distortion due to tracking error.

The Sonus Formula IV is a product of scientific investigation, of correct geometric and physical specifications, which the user can confidently employ with the highest quality audio components.

It was the first of it's kind and remains a superior choice for the purpose of approaching the ultimate transcription potential of high quality pickups.


Effective length: 240mm

Pivot: hardened steel needle resting in concave jewel rondel

Pivot friction: below 0.005g at headshell

Effective mass: 4.05g

Tracking error: 0.15 degrees/cm

Arm to amplifier wiring: 137cm miniature coaxial cable


instruction/owners manual  English

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Sonus Formula IV owners manual, service manuals and schematics are for reference only and the Vinyl Engine bears no responsibility for errors or other inaccuracies. The PDF files are provided under strict licence. Reproduction without prior permission or for financial gain is strictly prohibited. This website is not affiliated with or sponsored by Sonus.