Libra vs Spartacus 300B
The Spartacus 300B's signal-to-noise is 112 dB against the Libra's 90 dB, its output impedance 0.5Ω against 80Ω, and its input impedance 1500Ω against 90Ω. Both share class (A).
AI-generated product photo — not official manufacturer imagery.
AmplifiersPre-AmplifiersTube Amplifiers
Estimated price (community-sourced)
$78,467.80
Around — community and catalog average, updates slowly
About the Libra
Thrax Audio Libra is a flagship two-box, fully balanced 300B tube preamplifier designed around a true differential pure Class A triode gain stage. It uses two 300B tubes per channel, features post-amplification volume control, dual-mono architecture, independent outputs for bi-amplification, a fully balanced tape loop, home theater bypass, trigger output, and an external dual-mono power supply with a choke-input rectifier. Thrax describes it as a statement preamplifier built for low noise, high transparency, and modular serviceability.
Specifications
Power Specifications
Amplification power output and characteristics
- Amplifier Class
- A
- Input Impedance
- 90Ω
- Max Input Voltage
- 5.0V RMS
Analog Output
Analog signal output specifications
- SNR
- 90 dB
- Output Voltage
- 10.0V RMS
- Output Impedance
- 80Ω
Connectivity
Input and output connections
- Bluetooth
- No
- Wi-Fi
- No
- Ethernet
- No
- Analog Inputs
- XLR, RCA
- Analog Outputs
- XLR
Physical Dimensions
Size, weight, and appearance
- Dimensions
- 430 × 150 × 450 mm (W × H × D)
- Weight
- 26 kg (57 lbs)
Specifications are community-contributed and may not be accurate or complete. Verify all details with the manufacturer before making purchasing decisions. Terms & Conditions