
NAT Audio · Vacuum Tube Line Stages
Symmetric
A reference-grade balanced line stage defined by pure triode, zero-feedback design.
The Symmetric serves as the definitive reference for balanced pre-amplification in the NAT Audio catalogue. By utilising a transformer-coupled, class A circuit with an absolute zero-feedback topology, it removes the colouration and phase anomalies typical of conventional designs, ensuring the music remains entirely faithful to the source.
At the core of its architecture is a dual-mono configuration that maintains complete physical and electrical separation between channels. This design, paired with a massive power supply capable of delivering 300 joules of energy, provides the stability and authority required to drive even the most challenging interconnects and power amplifiers with effortless ease.
Sonically, the Symmetric is characterised by a rare combination of holographic imaging and harmonic richness. It avoids the clinical sterility of many modern balanced components, offering instead a fluid, organic presentation that excels in resolving low-level micro-dynamics and inner textures. For the listener, this translates to a profound, fatigue-free connection to the performance, grounded in a remarkably silent, deep background.
Key Features
01
Transformer-coupled output
Custom-wound, wide-bandwidth nano-crystalline transformers eliminate coupling capacitors for total signal purity.
02
Relay-based attenuation
A 96-position shunt-type volume network uses silver-contact relays and laboratory-grade resistors for transparent control.
03
Zero-feedback design
Pure class A triode topology avoids negative feedback loops to preserve natural phase and harmonic structure.
04
Dual-mono architecture
Completely separate signal paths and power supplies for each channel ensure near-infinite stereo separation.
Chapter 01
Engineering Philosophy
The Symmetric is built on the principle that the finest signal path is the one that introduces the least interference. By shunning capacitors and using transformer coupling, NAT has created a pre-amplifier that behaves like a passive device while maintaining the high-current drive capabilities of an active triode circuit.
Chapter 02
Build and Materials
The construction is exceptionally rigid, utilising a 15mm aluminium front panel and an all-metal chassis designed to suppress mechanical resonance. Internally, the component selection is uncompromising, featuring 0.1% Vishay resistors, military-spec RF linear FETs, and gold-plated connectors on a teflon-based PCB.
Chapter 03
Sonic Signature
The Symmetric is praised for its neutrality and resolution. It provides a wide, deep soundstage where every instrument is placed with precision, yet it retains the lush, dense tonal palette that only the finest vacuum tube designs can offer. It is, above all, a mature instrument for those who prioritise the emotional weight of a recording.
Specifications
TypePure balanced vacuum tube line stage
Frequency response2 Hz to 300 kHz (-3 dB)
Gain10 dB (low) or 16 dB (high)
Input Impedance> 20 kohms
Output Impedance< 180 ohms (low gain) or < 350 ohms (high gain)
Dimensions (H × W × D)160 mm × 483 mm × 400 mm
Weight20.5 kg (net)
Finish optionsBlack
