NuPrime Evolution STA-SE Stereo Power Amplifier, Silver

The NuPrime Evolution STA-SE is a stereo power amplifier that combines two independent mono amplifiers with a GaN power supply in a slim chassis.

It is aimed at anyone who wants to combine the power of a power plant with the sensitivity of a good tube – without having to haul hundredweight transformer behemoths into the rack.

Why the Evolution STA-SE?

The heart is the ANC GaN power supply. Imagine high-end noise cancelling for your electricity: the supply actively monitors the line and cancels out interference in real time. This purity used to be achievable only with huge, outrageously expensive toroidal transformers. On top of that comes ODC technology, which corrects errors right at the components and pushes distortion down to 0.002 percent.

NuPrime describes the Evolution series as reference class: detailed, wide, relaxed. The STA-SE is the power source in it – 400 watts per channel, at 8 as well as 4 ohms, and according to the manufacturer with the warmth of a Class-A circuit («Class-A-like warmth»).

What you get

Thanks to the consistent dual-mono design, instruments stand razor-sharp on a wide, deep stage. The high switching frequency of 650 kilohertz exposes every detail of your source components – in the workshop we like to call it "Liquid Precision": it flows like liquid gold and still hits with the force of a hammer blow when the music demands it. Furutech RCA inputs and Eichmann speaker terminals provide clean connections; with first-class cables, the power amplifier thanks you audibly. Via the trigger input and output, the STA-SE switches on and off with your preamplifier – never again forget a power amplifier quietly glowing away.

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Who is the Evolution STA-SE suited for – and who not?

It is a true endgame device: even demanding electrostatic or magnetostatic speakers with a high appetite for current (up to 40 amperes of peak current) are driven effortlessly. Plainly put: if you are looking for the typically "muddy" or artificially sweetened sound of old classics, the STA-SE is almost too honest. It does not colour, it shows – a precision tool that gives you a truthful snapshot of your recordings.

Our verdict

One of the most exciting power amplifiers in its class: compact, cool, quiet and yet brutally commanding. If you want the melt of a tube but do not want to give up the authority and bass control of a 400-watt power plant, you are in the right place. The low noise floor pays off especially at night – details emerge out of nothing.

Technical specifications

• Type: Stereo power amplifier, dual mono, Class-D hybrid with ODC
• Output power (RMS): 2 x 400 watts at 8 and 4 ohms
• Power supply: ANC GaN with active noise cancellation
• Switching frequency: 650 kilohertz
• Distortion (THD+N): 0.002 percent at 5 watts
• Frequency response: 10 hertz to 50,000 hertz (-3 dB)
• Signal-to-noise ratio (S/N): 110 decibels at 100 watts
• Input impedance: 47 kilohms
• Peak current: up to 40 amperes
• Filter capacitance: 52,000 µF total
• Connections: Furutech FP900 RCA, balanced XLR, Eichmann binding posts, trigger input and output
• Dimensions (W x H x D): 430 × 57 × 375 mm
• Weight: 9.0 kg
• Colour: Silver
• What's in the box: Power amplifier, power cable, trigger cable, user manual

FAQ

Does the STA-SE really deliver the same power at 4 and 8 ohms?
Yes. The GaN power supply works so controlled that the power amplifier stably delivers 2 x 400 watts RMS at 8 as well as 4 ohms. Where many amplifiers collapse at low impedance, the STA-SE keeps control – ideal for current-hungry or capacitive speakers.

What does gallium nitride (GaN) bring compared to classic silicon?
GaN semiconductors switch significantly faster and more efficiently. This allows a very powerful power supply in a small space that generates less heat and reacts lightning-fast to the dynamic jumps of the music. The result is a calm, black background.

Is the STA-SE a Class-D power amplifier – doesn't that sound harsh?
It is Class-D, but a special one. Thanks to ODC error correction and the high switching rate of 650 kilohertz, it avoids the typical digital harshness and sounds natural and fine, more like a good Class-A circuit than a switching amplifier.

Does the STA-SE suit my speakers?
In the vast majority of cases yes – especially power-hungry or electrically tricky speakers benefit. Which preamplifier and power amplifier combination suits your room and your speakers, we are happy to clarify with you in person at HD Zürisee in Wädenswil.

Why buy the NuPrime Evolution STA-SE at HD Zürisee?
We are an experienced specialist shop on Lake Zurich and know on which speakers such a power amplifier shines and on which it does not. Plus our own technician for delivery and setup, honest advice on the matching preamplifier and proper warranty handling. Call or write to us.

Goes well with

A power amplifier is only as good as what hangs in front of and behind it – this is how the chain sensibly grows further:

• Source and preamplifier: The DAC Evolution DAC-2 from the same series comes with a reference preamplifier and can drive the STA-SE directly. Alternatively a separate preamplifier.
• Digital: A streamer or the Evolution Stream Server as a Roon hub – only necessary if you listen to music from the network; a subscription is not required.
• Speakers: Speakers with a hunger for current are its territory – with 400 watts per channel you can afford to be choosy.
• Cabling: XLR cables for the balanced connection and a good power cable.
• Mains: If you like it clean: the Pure AC-6 power conditioner from the Power series. Honestly, the audible effect depends on the rest of the system – we will tell you openly whether it is worthwhile for you.
• More from the series: NuPrime