
NAT Audio · Vacuum Tube Power Amplifiers
Magma M Evo
A reference-grade single-ended amplifier delivering immense power with uncompromising purity.
The Magma M Evo represents the pinnacle of our single-ended vacuum tube development, engineered for those who demand the sonic transparency of a DHT design without the limitations of low power output. By utilizing a heavy-duty 6C21 triode, the amplifier achieves a unique balance of extreme power and the delicate signal handling required for high-end reproduction.
At the core of the Magma M Evo is a circuit architecture that prioritizes the shortest possible signal path. By eliminating coupling capacitors and inter-stage transformers, we ensure the input signal remains entirely uncorrupted. This rigorous commitment to purity is supported by a heavily overbuilt power supply featuring over 500 Joules of energy storage, which provides the stability needed for effortless dynamic swings.
The sonic character of the Magma M Evo is one of immense clarity and weight. It does not lean into the lush, soft signatures often associated with traditional tubes; instead, it offers a fast, percussive, and articulate presentation that maintains the natural timbre and harmonic structure of a performance. It functions as a precise instrument, capable of driving complex loads with the authority and ease typically reserved for high-power push-pull designs.
Key Features
01
Direct-heated triode architecture
Utilises a military-grade 6C21 power tube for exceptional linearity and high-power delivery.
02
Zero global feedback
A refined circuit design that maintains signal integrity by avoiding the common distortions associated with feedback loops.
03
Selectable power modes
Allows the user to switch between 100W and 50W settings to best match loudspeaker sensitivity and performance needs.
04
Minimalist signal path
Features a design devoid of coupling capacitors and inter-stage transformers for maximum transparency.
05
Automatic bias control
An integrated system that ensures long-term stability and optimal tube operation without manual maintenance.

Chapter 01
Design & Philosophy
The philosophy behind the Magma M Evo is the removal of barriers between the source and the loudspeaker. We treat the amplifier as a wide-bandwidth, high-current instrument rather than a traditional tube device. By focusing on a zero-feedback configuration, we ensure the natural harmonic texture of the music is preserved throughout the entire amplification process.

Chapter 02
Build & Materials
Housed in a CNC-machined aluminium chassis with a 20mm thick front panel, the Magma M Evo is built for industrial-grade longevity. It incorporates custom-wound output transformers and an expansive power supply, resulting in a unit that balances massive power storage with the refined component quality of an aerospace-grade product.

Chapter 03
Listening Notes
The Magma M Evo provides a rare combination of sheer muscle and microscopic detail. It handles complex, multi-layered recordings with complete composure, allowing for deep soundstage mapping and distinct spatial imaging. It is an ideal solution for listeners who require the honesty of a reference-grade amplifier combined with the rhythmic drive of a high-power design.
Specifications
TypeSingle-ended class A monoblock
Frequency response8 Hz to 80 kHz
Sensitivity1.4 V RMS for 100 W
ImpedanceInput: 100 kohms
Power handling100 W (high mode) or 50 W (low mode)
Dimensions (H × W × D)350 mm × 350 mm × 520 mm
Weight45 kg per unit
Finish optionsBlack or silver
