NuPrime AMG PRA Preamplifier

Advanced Solid-State Preamp with the Rich Harmonics of Vacuum Tube Gear

The NuPrime AMG PRA goes beyond being a transparent preamp with 1M Ohm input impedance and the best analog source inputs. A user-selectable four-stage "Active Low Frequency and Harmonic Gain" control give it distinctive characteristics to enhance your speaker performance for a world-first in preamplifier design. You've never heard anything like it until you experience the AMG PRA.

The design goal for AMG PRA was to deliver a transparent sounding analog preamp with distinctive characteristics. Several new design concepts were developed and used in the AMG PRA besides 1MΩ input impedance to achieve the very best from its analog inputs. Inputs and outputs have a fully balanced design, featuring both single-ended RCA and balanced XLR connections.

'Enlarge' Your Speakers

This preamp can help 'enlarge' your speakers. With other preamps, users of smaller bookshelf speakers often notice a distinct drop in bass response with some audio tracks. You can compensate for that perceived deficiency with the AMG PRA. Instead of a simple "Bass Boost" function that lifts a targeted low-frequency band, the AMA PRA's user-selectable four-stage "Active Low Frequency and Harmonic Gain" control compensates for the lack of bass presence. It permits the addition of some bass extension and a more natural roll-off too.

Airy and Velvety Tube-like Sound

If you enjoy the rich sound of vacuum tube gear but want to avoid typical maintenance issues, the AMG PRA is the solution. The ultra-wide bandwidth low noise JFET input feeds the latest generation of NuPrime’s "Single-Ended, Non-Negative Feedback" Class A module and a MUSES8920 Op-amp input amplification stage. This circuitry produces harmonics similar to vacuum tube preamps, which have what might well be termed an airy and velvety sound.

A non-feedback low-frequency domain Frequency Harmonic Modulation circuit provides minimum phase distortion and tone error. Additional features such as the two-stage gain control and invertible phase control increase the compatibility of the AMG PRA with other power amplifiers.

Isolated Power Circuitry

The layout of the AMG PRA takes excellent care in isolating the sensitive audio signals from the power circuitry. The power circuitry comprising of a star topology power and ground layers is built on one board while a separate board houses the pre-amplification circuit. An isolation layer separates these two boards, which further minimizes interference. The effect is a highly transparent sound that is natural and not over etched.

The AMG series front panel embodies its spirit. It is milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process. Design elements such as the 3D "floating" logo, the curved surface around the front panel switch, and diamond-cut edge bring the quality of ultra-high-end audio products to the affordable range of the AMG series.

Product Features

Overview

Compact audiophile line stage preamplifier
Fully balanced design
1M Ohm input impedance
Harmonic richness similar to vacuum tube preamps
Single-ended RCA and balanced XLR inputs and outputs
User-selectable four-stage "Active Low Frequency and Harmonic Gain"
Ultra-wide bandwidth low noise JFET input
Latest generation NuPrime’s "Single-Ended, Non-Negative Feedback" Class A module and MUSES8920 Op-amp input amplification stage
Non-feedback low-frequency domain Frequency Harmonic Modulation circuit
Two-stage gain control
Invertible phase control
Isolated power circuitry: power circuitry comprising of a star topology power and ground layers is built on one board, while a separate board houses the preamplification circuitry
Front panel milled from a 15mm harden aerospace aluminum alloy using a four-axis CNC machine with a diamond cutter through a 48 steps process

Front Panel Settings

Left Toggle Switch: Output Gain
- Upwards: High Gain
- Downwards: Low Gain
Right Toggle Switch: Output Phase
- Upwards: Phase Invert
- Downwards: Phase Normal
Left knob: Loudness Compensation
- Turn the knob to switch between Loudness Compensation
Right Knob: Power and Input Selector and Volume
- Briefly press for 3 sec to On/Off standby mode
- Brief press to Input Selector
- Turn the knob to adjust Volume

Product Specs

Frequency Response: 10Hz to 200kHz; +-0 to -0.1dB
THD: 0.008 %
Input Impedance: Balanced IN: 1M Ohm @ 10 Hz ~ 200 kHz; Line IN: 1M Ohm @ 10 Hz ~ 200K Hz
Rated Output Voltage: 2 V (LINE) / 4V (BAL) @ 100 Ohm
S/N: 95 dB
Loudness Compensation: 2.2 dB (125 Hz); 4.5 dB (100 Hz); 5.3 dB (75 Hz)
Gain: 3.2 (High) / 2.1 (Low)
Worldwide AC voltage: (90VAC~130VAC // 210VAC~ 250VAC) With Voltage Select Switch*
AC Fuse: Slow-blow, 1A, 250VA
Dimensions: 9.25" W x 11.8" D x 2.1" H (including feet)
Weight: 5.5 lbs.

*Note: Make sure that the AC Voltage selector switch at the bottom of the unit is switched to the appropriate voltage for your country. All AMG series are shipped with the switch set to 230V AC in order to prevent accidental damage.

Product Warranty

1 Year

Parts & Labor

NuPrime Warranty Information

Product Manual

	NuPrime AMG PRA Manual (PDF Format)

	NuPrime AMG PRA Quick Start Guide (PDF Format)

2022 Editors’ Choice Award - The Absolute Sound

"I really enjoyed the NuPrime AMG PRA preamplifier and the AMG STA power amplifier. I didn’t waste any time hand-wringing over Class D, and barely even mention it in my review—for good reason. The STA/PRA combination sounded great, with a heavy low end, a relaxed and pleasant midrange, and just enough sparkle in the upper end to make cymbals shimmer. The interesting loudness function on the PRA and the very nicely made remote control were the kind of simple but useful upgrades over a standard preamp that made this combination feel premium. For many folks, I suspect a single STA will provide enough power, but for those who have more difficult-to-drive speakers, or those who want a massive amount of power on tap and ready to go, the monoblock setup is fantastic. This is a system worth trying and comes highly recommended."

- Drew Kalbach, Stereophile, September 9, 2021