Power amplifiers mono — NAT Magma Evo

The Magma Evo is a single-ended mono block power amplifier from NAT Audio, made in Serbia which the brand calls one of the most powerful and innovative single-ended, single-tube amplifiers built anywhere in the world. Named for the orange-red glow of its output tube's anode, so reminiscent of a volcano's own magma, the Magma Evo is NAT's newest flagship, priced at $95,000 and positioned above the earlier Magma Limited Edition and Magma M in the brand's power amplifier hierarchy.

Key specs that matter

The output stage is built around the GM100 directly heated triode (DHT), the highest-power vacuum tube manufactured specifically for audio use, capable of dissipating up to 1,000W of heat. Input and driver circuitry uses 6N6P-IR (also cited as 6N2P-ER in some sources) double-triode tubes, chosen as New Old Stock (NOS) military-grade components for neutral sound - NAT specifically favours NOS tubes from renowned manufacturers, often to military specification, wherever this is possible. Input sensitivity is 1.25-2.7V RMS depending on configuration, with input impedance at 100k ohms. Two power modes are selectable - a high-power setting reaching up to 170W, or a moderate setting around 50W, both delivered in pure DHT single-ended configuration. A custom-designed, wide-bandwidth 1200W output transformer, built entirely in-house by NAT, achieves an 8Hz-70,000Hz bandwidth, a rare specification for a single-ended design at this power level. Output taps for 4 and 8 ohm loads use high-mass, multi-connection laboratory-grade connectors, and NAT states the Magma Evo can comfortably drive any load from 1.5 ohms to over 32 ohms. The driver circuit path uses no coupling capacitor or any other passive component beyond the output transformer section itself - meaning no resistors sit anywhere in the direct signal path, an uncommon architecture NAT credits for audibly faster signal transfer. The power supply incorporates a built-in AC conditioner and soft-start circuitry, specifically avoiding high-voltage and current stress during turn-on to improve long-term reliability. Each monoblock weighs 50kg.

Sound and use context

The combination of a capacitor-free, resistor-free direct signal path with the custom wide-bandwidth output transformer is engineered for speed and transparency that NAT states is easily audible, an uncommon goal for a single-ended, zero-global-feedback design at this power level.

Pairing

This broad load tolerance means it partners electrostatic, magnetostatic, dynamic or any other loudspeaker technology directly, without the impedance-matching concerns that typically constrain single-ended triode amplifiers to a narrow range of compatible speakers.

Alternatives

NAT's own Magma M and Magma M Evo sit below this flagship at correspondingly lower prices and power output, sharing the same core single-ended, zero-feedback DHT approach, worth considering instead if the Magma Evo's price and 170W ceiling exceed what a specific system and loudspeaker pairing require.