NuPrime AMG PRA Preamplifier, Grey

The NuPrime AMG PRA is a purely analog preamplifier that controls volume via a highly linear MUSES72320 circuit and features four-step bass control and switchable phase control.

In short: this is the control center between your sources and the power amplifier – no digital detour, but a highly linear volume control instead. Few knobs, big effect.

Why the AMG PRA?

A good preamplifier doesn't draw attention to itself – it adds nothing and takes nothing away. That is exactly what the AMG PRA aims for: separate circuit boards keep interference out, the two-stage gain (High/Low) adapts it to different power amplifiers, and the switchable phase control keeps the signal correctly polarized.

Volume is handled by a highly linear MUSES72320. According to NuPrime, at step 92 the output level matches the input level exactly (0 dB) – so the preamplifier does not attenuate the signal when you turn it all the way up.

NuPrime describes the AMG series as having fine detail, rich tone and spatial imaging – separates with a character of their own. The PRA stands under the motto «Shape your listening experience»: with the bass adjustment you really are allowed to turn a knob on the preamplifier – here it is explicitly permitted.

What you get

On the input side, the AMG PRA accepts balanced XLR and unbalanced RCA sources, each with 1 MΩ input impedance – behind the low-noise JFET input stage in Class-A design, which takes in the source gently. Volume is controlled by a MUSES72320. On the output side, 2 V via RCA and 4 V balanced are available – enough level for practically any power amplifier.

The highlight is the four-step «Active Low Frequency and Harmonic Gain» control: a targeted bass boost with which you compensate for small speakers or a sluggish room, without reaching for the equalizer right away. In addition there is a finely graduated loudness compensation for quiet listening sessions. It is operated by remote control for source and volume.

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Who is the AMG PRA for?

For anyone who deliberately builds their system from a preamplifier and power amplifier and wants an honest, analog preamplifier with a few useful adjustments. Ideal as a partner to the AMG ONE and STA power amplifiers.

Honestly: If you expect a built-in DAC, streaming or phono stage, this is not for you – the AMG PRA is purely analog and concentrates on preamplification. This very reduction is its advantage, but you have to want it.

Our verdict

The AMG PRA is an understated, cleanly built preamplifier that pays off in the right combination. The Absolute Sound (Drew Kalbach, 2021) tested the AMG PRA together with the AMG STA and notes that the preamplifier and power amplifier share the same form factor and are clearly meant to work as a duo. In The Absolute Sound's Buyer's Guide 2024, according to NuPrime, the AMG PRA is listed under «The Greatest Bargains in High-End Audio». We at HD Zürisee in Wädenswil appreciate how quietly and neutrally it does its job.

Technical specifications

• Design: purely analog preamplifier (no DAC)
• Input stage: low-noise JFET, Class-A
• Volume control: MUSES72320 (highly linear); step 92 = 0 dB (input = output)
• Bass control: 4-step (Active Low Frequency and Harmonic Gain)
• Phase: switchable phase inversion
• Gain: 2-stage – 10.10 dB (High) / 6.44 dB (Low); voltage gain 3.2 / 2.1
• Inputs: XLR balanced and RCA, 1 MΩ each (nominal input 8 V XLR / 4 V line)
• Nominal output voltage: 2 V (RCA) / 4 V (XLR) @ 100 Ω
• Frequency response: 10 Hz – 200 kHz (+0 / -0.1 dB)
• THD: 0.008 %
• Signal-to-noise ratio: 95 dB
• Loudness compensation: 2.2 dB (125 Hz) / 4.5 dB (100 Hz) / 5.3 dB (75 Hz)
• Construction: separate circuit boards, 15 mm aluminum front panel, CNC-machined chassis
• Control: remote control for source and volume, programmable remote code
• Dimensions (W × H × D): 235 × 55 × 300 mm
• Weight: 3.5 kg
• Color: Grey
• Warranty: 2 years

FAQ

Is the NuPrime AMG PRA an analog preamplifier?
Yes, the AMG PRA is a purely analog preamplifier without an integrated DAC. It accepts analog sources via XLR and RCA, controls the volume via a highly linear MUSES72320 circuit and passes the signal on to your power amplifier. Digital sources need a DAC in front of it.

What does the bass control of the AMG PRA do?
The four-step Active Low Frequency control lets you raise the bass range in a targeted way. This helps compensate for small speakers or a difficult room without bending the rest of the sound. You choose the step to suit your speakers and placement.

Which power amplifier suits the AMG PRA?
The AMG PRA is matched to the NuPrime AMG power amplifiers – the AMG ONE mono power amplifier or the AMG STA stereo power amplifier. Thanks to the switchable phase control and two-stage gain, it also works with many other power amplifiers. We are happy to help you work out which combination fits.

Does the AMG PRA have balanced XLR connections?
Yes. The AMG PRA handles balanced XLR as well as unbalanced RCA signals, each with 1 MΩ input impedance. On the output side it delivers 2 V via RCA and 4 V balanced. This lets it integrate cleanly into differently configured systems.

Why buy the NuPrime AMG PRA at HD Zürisee?
Because a preamplifier is the heart of the system and has to match the power amplifier and speakers. We advise you on the right combination, check the levels and take care of setup and service with our own technician. Call us, write to us or drop by in Wädenswil.

Goes well with

The AMG PRA is the control center – what you connect to it determines the character of the system:

• Power amplifier: The AMG power amplifiers are the obvious partners: two AMG ONE as monoblocks or the AMG STA-SE as a stereo power amplifier, bridgeable later. More on this at power amplifiers.
• Digital: The PRA is purely analog. For streamers, PC or CD you need a DAC in front of it – the AMG DAC from the same series fits; a streamer takes care of playback.
• Speakers: With the bass adjustment, even smaller speakers or difficult rooms cope better – we advise you on the combination.
• Connection: Where the source can do XLR, use XLR cables; otherwise cables with RCA fit.
• More from the series: NuPrime