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Square Tube

Square Tube is a new, unique and innovative way to assemble the vacuum tubes to get rid of their limits.

This trademarked amplification schematic opens new technical perspective, but more important, gives striking and surprising results. The tubes not only provide their well know smoothness, but also an extreme precision in micro details. The voices (acapella) are expressed with unreached natural, without any halo or reverb effects.  The instruments are perfectly focused (and can be spatially tracked) with an unusual stability. The dynamic reveals the most subtle percussions, with unexpected and unmatched energy! Not “tube” nor transistor, come try the Kora sound!

The Kora Line

The whole Kora line is designed around the Square Tube innovation.

To start with, we developed three integrated amplifiers engineered to suit the needs of the most demanding music lovers. All devices are made on the same basic schematic and key components. The amplifiers combine the Square Tube® innovation with linear power transistors. The transistors don’t participate to the amplification of the signal, which instead takes place in the tubes exclusively. The transistors sole purpose is only to provide the current to the speakers. They are used as impedance adaptor with a gain of 1. The main difference between the versions (TB140, TB200, TB400) is essentially in the power supply section and the number of output transistors.

Gamme KORA

We are currently concocting a whole range of products.


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TB140 : the TwitteringMachines review

“The Kora TB140 delivers an addictive and rather unique presentation offering a deep dive into music’s inner workings without sounding analytical or contrived.”

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A French take on tube amplifiers

“For now, I’ll just say that Kora TB400 is the best amplifier I’ve ever listened to.”

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Integrated Amplifier : KORA TB140

Discover the enthusiastic latest review of the TB 140 by Pierre Fontaine and Laurent Thorin for Vumètre magazine.

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