Knif Audio Sora

The Knif Sora is a mastering-grade saturation and distortion device that combines SQ Philips NOS pentode tubes, Lundahl transformer options, a versatile crossover network and precision stepped control to deliver highly controllable harmonic shaping for professional mastering and mix applications.

Overview

Knif Audio designs the Sora as a precision tube saturation system that offers absolute repeatability and deep control of the harmonic spectrum. The device uses a push pull pentode circuit built around SQ Philips NOS valves and selectable Lundahl interstage transformers. The silicon iron option provides familiar transformer character while the nanocrystalline type delivers near zero hysteresis and complete transparency across the audio range. The signal path uses OPA828 JFET input operational amplifiers for clean gain and transient accuracy.

MS Matrix and Crossover Filters

The integrated MS matrix enables engineers to encode and decode mid and side signals for selective harmonic manipulation within complex stereo material. The comprehensive crossover network allows frequency selective processing without shifting the overall tonal balance. Users select which band enters the distortion circuit while retaining a flat response outside the chosen range.

Gain Structure and Parallel Processing

Sora offers wide range gain adjustments for flexible drive control, enabling subtle warming, thick parallel tone or overt distortion. Parallel blend uses an Alps Blue potentiometer to align dry and processed signals while maintaining precise channel balance. The output attenuation stage ensures predictable gain staging back into the mastering chain.

Symmetry and Harmonic Control

The symmetry parameter gives powerful control over the distortion spectrum, allowing users to emphasise or reduce even order harmonics and tightly sculpt the overall harmonic balance. Engineers can shift the phase and perceived tone of the saturation effect with accuracy that suits critical mastering workflows.

Construction and Power

All rotary controls, except the crossfade, use Elma stepped switches for absolute repeatability in mastering sessions. Sora operates from six high voltage supplies and three low voltage supplies, with separate anode and adjustable screen grid voltages that maintain consistent dynamic response. The rear panel hosts gold plated Neutrik XLR connectors for reliable interfacing.

Why Choose the Knif Sora

• Achieve musical tube coloration with precision rather than guesswork
• Shape harmonic content with confident repeatability in a mastering context
• Switch between coloured and transparent transformer tones instantly
• Process specific frequency bands without altering overall balance
• Combine parallel signals smoothly for subtle enhancement or heavy saturation
• Maintain accurate stereo imaging with MS processing
• Trust a mastering tool built for longevity, reliability and absolute control

• MS encoding and decoding
• Comprehensive crossover filtering for frequency selective processing
• Wide input gain and output attenuation ranges
• Parallel processing via Alps Blue crossfade control
• Symmetry control for harmonic spectrum management
• Push pull saturation circuit using SQ Philips NOS pentode tubes
• Selectable silicon iron or nanocrystalline Lundahl interstage transformers
• OPA828 JFET input operational amplifiers for transparency
• Stepped Elma rotary controls throughout the unit
• Six regulated high voltage supplies and three regulated low voltage supplies
• Gold plated Neutrik XLR input and output connectors
• Maximum input and output level of +26 dBu
• Noise floor of ≤ -90 dBu in typical use
• Frequency response up to 50 kHz depending on filter configuration
• Dimensions of 430 × 352 × 88 mm and weight of 10.2 kg

This item, like everything we supply, comes with the complete support of our expert team. Our excellent technicians have been specifying, building and supporting studios for over twenty years. If you have any problems with installation, setup or everyday use, they’re never more than a click away, and always happy to help.

You can contact them here.