NuPrime AMG STA-SE Stereo Power Amplifier, Grey

The NuPrime AMG STA-SE is a Class-A+D hybrid stereo power amplifier that delivers 2× 130 watts into 8 ohms and can be bridged to mono operation for more power.

The abbreviation SE stands for Special Edition – NuPrime's revised version of the AMG STA. It combines a single-ended Class-A stage with a Class-D power section: the finesse of one world, the efficiency and power of the other. It sounds like an attempt to square the circle – and comes astonishingly close.

Why the AMG STA-SE?

The idea behind Class A+D: a single-ended Class-A input stage shapes the tone, while a double-feedback Class-D module delivers the power. The high switching frequency of over 700 kHz keeps the Class-D module clean, and because little heat is generated, the power amplifier runs cool and stable.

The whole thing is supplied by a linear power supply with a toroidal transformer – the reserve that makes the difference between “standing firm” and “collapsing” on powerful bass impulses. The JFET input stage with 1 MΩ takes in the preamplifier gently.

NuPrime describes the AMG series as having fine detail, rich tone and spatial imaging – separates with a character of their own. The STA-SE stands under the motto «Power with poise»: strength with composure, instead of flexing muscles.

What you get

2× 130 watts into 8 ohms, 2× 200 watts into 4 ohms: enough control that even low-efficiency speakers don't flail about. The very low output impedance (20 mΩ) ensures a firm grip on the bass without the midrange drying out.

Need more? Bridged, the STA-SE works as a mono power amplifier with around 300 watts into 8 ohms (320 watts per amplifier into 4 ohms) – two of them then make a powerful monoblock pair. Switching is done with a stereo/mono switch, input via XLR or RCA. This way the power amplifier grows with your demands.

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Who is the AMG STA-SE for?

For anyone looking for a compact, powerful stereo power amplifier with the option of mono operation – ideal as a partner to the AMG PRA or AMG DAC. If you challenge your speakers, you will find plenty of reserve here.

Honestly: There are no sources, volume control or streaming here – the STA-SE is a pure power amplifier and needs a preamplifier in front of it. If you are looking for an all-in-one unit, you are better off with an integrated amplifier. If you deliberately separate preamplifier and power amplifier, you get a lot of power amplifier for the money here.

Our verdict

The AMG STA-SE is an astonishingly powerful, cool-running power amplifier with a hybrid Class-A+D signature. Christiaan Punter tested the SE version in July 2024 for HiFi-Advice and awarded it the HFA Award: he said it improved on all the points he had criticized in the original STA, and sounds more natural than any other Class-D amplifier he has heard. We at HD Zürisee in Wädenswil like how confidently and unflustered it handles even loud passages.

Technical specifications

• Design: Class-A+D hybrid stereo power amplifier (single-ended Class-A + double-feedback Class-D), bridgeable to mono («Direct-Inject-Bridge»)
• Switching frequency: over 700 kHz
• Input stage: JFET, 1 MΩ
• Inputs: XLR and RCA, stereo/mono switch
• Power supply: linear power supply with toroidal transformer
• Power (stereo): 2× 130 W @ 8 Ω, 2× 200 W @ 4 Ω
• Power (mono, bridged): 300 W @ 8 Ω, 320 W per amplifier @ 4 Ω
• Rated/peak current: 10 A / 15 A
• Gain: 28.3 dB (stereo) / 34.3 dB (mono)
• Sensitivity: 1.2 Vrms (stereo) / 0.95 Vrms (mono)
• Input impedance: 1 MΩ
• Output impedance: 20 mΩ
• Signal-to-noise ratio: 100 dB @ 10 W
• THD+N: 0.006 %
• Frequency response: 10 Hz – 50 kHz (±0.2 dB @ 8 Ω), 58 kHz @ -3 dB
• Dimensions (W × H × D): 235 × 55 × 300 mm
• Weight: 4.5 kg
• Color: Grey
• Warranty: 2 years

FAQ

How much power does the NuPrime AMG STA-SE have?
In stereo operation the AMG STA-SE delivers 2× 130 watts into 8 ohms and 2× 200 watts into 4 ohms. Bridged as a mono power amplifier, it is up to 320 watts into 4 ohms. This lets it drive even more demanding speakers with ease.

Can I bridge the AMG STA-SE as a mono power amplifier?
Yes. The AMG STA-SE can be bridged into mono mode and then delivers around 300 watts into 8 ohms. This way you can build a powerful monoblock setup with two units or run one unit in stereo – depending on your system and speakers.

What does the Class-A+D hybrid concept mean?
It combines a single-ended Class-A stage with a double-feedback Class-D module. This is meant to unite the sonic finesse of Class A with the efficiency and power of Class D. The high switching frequency above 700 kHz and the JFET input stage keep detail and calm high.

Which preamplifier suits the AMG STA-SE?
The AMG STA-SE is a pure power amplifier and needs a preamplifier in front of it. From the same house, the NuPrime AMG PRA fits, alternatively the AMG DAC with volume control. Thanks to the 1 MΩ input stage, it also works well with many other preamplifiers.

Why buy the NuPrime AMG STA-SE at HD Zürisee?
Because the power has to match your speakers and your room. We advise you on stereo or mono operation and the right preamplifier, and take care of installation and service with our own technician. Call us, write to us or drop by in Wädenswil.

Goes well with

The AMG STA-SE is meant to be a power amplifier that grows with you – this is what the upgrade path looks like:

• Preamplifier: In front of it belongs a preamplifier – the AMG PRA also brings an adjustable bass control. If you play digital sources, take the AMG DAC, which also handles the volume (DAC).
• Expansion: Start with one STA-SE in stereo operation. If a second one is added later, you bridge both to mono – two power amplifiers become a monoblock pair. Anyone who upgrades later hasn't overdone it, but planned ahead.
• Speakers: With 2× 130 W into 8 Ω and 2× 200 W into 4 Ω, it is a solid basis for demanding speakers – we will work out with you what suits your room and taste.
• Connection: Input is via XLR or RCA: XLR cables for a balanced preamplifier, otherwise cables with RCA.
• More from the series: NuPrime