Libra

The Pinnacle of Preamplification

Statement differential balanced 300B tube preamplifier of the 21st century.

Two 300B tubes per channel in a true balanced differential pure Class A triode configuration.
Post-amplification volume control for the lowest noise and maximum signal integrity.
Dual-mono design with two independent outputs per channel for bi-amplification setups.
Fully balanced Tape Loop for professional tape recorder integration.
Home theater bypass and trigger output for seamless system integration.
External dual-mono power supply with choke input rectifier for noise-free operation.
Microprocessor-controlled operation with status display and advanced menu system.
Special filament heating circuit for harmonic richness and tube protection.
DC-coupled input and output for ultimate transparency.
Modular construction for easy servicing and upgrades.

The Libra is more than just a preamplifier—it’s the heart of a world-class audio system. Designed to complement the legendary Spartacus 300 power amplifier, Libra combines the timeless warmth of 300B tubes with cutting-edge engineering to deliver a listening experience that is both pure and powerful. With its modular construction, dual-mono design, and innovative features, Libra sets a new standard for high-fidelity preamplification.

The 300B Tube, Reimagined

At the core of Libra lies the 300B tube, revered for its harmonic richness and linearity. Libra employs two 300B tubes per channel in a true balanced differential pure Class A triode configuration. This unique gain stage delivers a tonal spectrum that is both dense and crystalline, revealing layers of detail in your music that you never knew existed.

When paired with the Thrax Spartacus 300, Libra completes a full 300B signal amplification path, creating a system that redefines what’s possible in high-fidelity audio. The result is a sound that is both stunningly transparent and emotionally engaging.

Post-Amplification Volume Control for Ultimate Purity

Libra features a post-amplification volume control, ensuring the lowest possible noise and maximum signal integrity. This design allows the preamplifier to deliver a clean, uncolored signal, free from the distortions often introduced by traditional volume control circuits.

Dual-Mono Design for Uncompromising Performance

Libra is built as a dual-mono preamplifier, with two independent outputs per channel. Each output is adjustable for level offset, making it ideal for bi-amplification setups. Whether you’re pairing a single-ended triode amplifier for mid/high frequencies with a powerful push-pull amplifier for bass, Libra ensures seamless volume synchronization and perfect integration.

Fully Balanced Tape Loop for Professional Integration

For audiophiles and professionals alike, Libra includes a fully balanced, isolated, and buffered Tape Loop. This feature is designed to integrate professional tape recorders like Studer and Ampex, allowing you to fully harness the richness and depth of your master tapes.

Home Theater Bypass for Seamless Integration

Libra is designed to fit seamlessly into modern audio systems. Its home theater bypass feature allows you to integrate your stereo system into a home cinema setup, while a trigger output enables automatic power control of hard-to-reach amplifiers.

Innovative Power Supply for Noise-Free Operation

Libra’s external dual-mono power supply features a choke input rectifier for the lowest possible switching noise. This design isolates all mains AC and rectifier noise in the power supply, while final regulation and filtering occur near each element in the amplification circuit. The result is a preamplifier that operates with explosive dynamics and tonal purity.

Microprocessor Control for Safety and Convenience

Libra is equipped with a microprocessor-controlled operation system, ensuring safety and ease of use. A large color LCD displays the system status, visible from your listening position, while a comprehensive menu system provides access to advanced features. This keeps the front panel clean and aligned with Thrax’s signature minimalist design.

Special Filament Heating Circuit for Harmonic Richness

A special filament heating circuit enhances the harmonic richness of the 300B tubes while protecting them for long life and consistent performance. Combined with the auto-bias system, which compensates for tube aging, Libra ensures optimal operation with any 300B tube.

DC-Coupled Input and Output for Ultimate Transparency

Libra features DC-coupled input and output, ensuring the ultimate in transparency and signal integrity. This design eliminates the need for coupling capacitors, preserving the natural character of your music.

Experience the Libra Difference

The Libra isn’t just a preamplifier—it’s the soul of your audio system. Its combination of timeless tube technology and modern engineering makes it the ultimate choice for those who demand the best.

Discover the power, purity, and passion of the Libra—and hear your music like never before.