
NAT Audio · Vacuum Tube Line Stages
Magnetic
A reference-grade line stage defined by pure triode, zero-feedback transformer coupling.
The Magnetic stands as a definitive reference in the NAT Audio catalogue, representing an uncompromising pursuit of direct signal reproduction. By employing a transformer-coupled design that eliminates all capacitors from the signal path, the circuit maintains a level of purity rarely achieved in vacuum tube amplification. Its dual-mono architecture ensures complete separation between channels, preserving the delicate spatial cues of the original recording.
At its core, the Magnetic utilises high-reliability, military-grade triodes in a pure class A, zero-feedback configuration. This design choice eschews corrective loops, allowing the natural timbre and harmonic structure of the music to emerge without the phase shifts or artifacts often introduced by standard pre-amplifier topologies. The result is a sound that is both authoritative and remarkably organic, avoiding the sterile clinicality of many modern electronic designs.
Sonically, the Magnetic is defined by a sense of ease and a profound, black background that lets low-level details bloom with natural weight. It offers a rich, textured midrange and a smooth, extended treble that avoids artificial hardness, providing a presentation that feels holographic rather than chiseled. This is a component for the dedicated enthusiast who demands a mature, unfiltered window into their music collection.
Key Features
01
Transformer-coupled circuit
Features custom-wound amorphous core output transformers to ensure a signal path entirely free of coupling capacitors.
02
Absolute zero feedback
The pure class A triode design avoids negative feedback loops, maintaining phase accuracy and signal integrity.
03
Relay attenuation
A computer-controlled, 96-position shunt-type relay network uses silver-contact relays and laboratory-grade resistors for transparent volume control.
04
Dual-mono construction
Independent power supplies and signal paths for each channel provide near-infinite stereo separation and stability.

Chapter 01
Design & Philosophy
The Magnetic is built on the belief that the signal path should be as direct and undisturbed as possible. By replacing standard resistive networks with custom amorphous-core transformers, NAT has created a pre-amplifier that functions as a passive-like conduit with the active driving power of a pure triode stage.

Chapter 02
Build & Materials
The build quality is substantial, featuring a 15mm thick aluminium front panel and a chassis designed to suppress resonance. Inside, the use of 0.1% Vishay resistors, silver input wiring, and approximately 500,000uF of power supply capacitance demonstrates a build philosophy that prioritises long-term reliability and extreme electrical stability.

Chapter 03
Sonic Signature
Listening to the Magnetic is a process of discovery. It does not impose an 'electronic' flavour on the music; instead, it presents the recording with a natural, breathing quality. The bass is deep and taut, the midrange is harmonically dense, and the overall perspective is one of relaxed, fatigue-free authority.
Specifications
TypeZero feedback vacuum tube line stage
Frequency response2 Hz to 250 kHz (-3 dB)
Gain12 dB (X4)
Input Impedance> 20 kohms
Output Impedance< 600 ohms
Dimensions (H × W × D)185 mm × 483 mm × 400 mm
Weight22 kg
Finish optionsBlack
