Nuprime Audio AMG STA
Image source — © Nuprime Audio
What is it?
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Model name
AMG STA
Input sensitivity (mV)
1200
Input impedance (balanced) (Ω)
1 000 000
Input impedance (single-ended) (Ω)
1 000 000
Output impedance (balanced) (Ω)
N/A
Output impedance (single-ended) (Ω)
0.02
Max current (A)
N/A
Output power (8Ω) (W)
130
Output power (4Ω) (W)
200
Gain (dBu)
26
Frequency response low +/- 3dB (Hz)
10
Frequency response high +/- 3dB (Hz)
50 000
Signal to Noise Ratio (dB)
100
Total Harmonic Distortion + Noise (0% global feedback) (%)
N/A
Total Harmonic Distortion + Noise (100% global feedback) (%)
0.006
Max power consumption (W)
N/A
Damping factor
N/A
Dimensions (mm)
55 x 235 x 300
Weight (kg)
4.5
Official link
The “Power Engine” is a low-power switching power supply (SMPS) for low voltages on the amp board. The large linear power supply provides high voltages for the Class-D power stage. According to the manufacturer, they have made a breakthrough in SMPS design that can rival linear power supplies. This “Power Engine” is the first use of such a design for AMG STA-SE.
NuPrime is a small AMG STA power amplifier capable of delivering 300 watts at 8 ohms in bridge mode and 320 Watts at 4 ohms load. He achieves such indicators by using a clever scheme that combines two cascades – one in class A on JFET transistors and the second in class D. In traditional stereo mode, the power is 120 watts per channel at 8 ohms and 200 watts at 4 ohms.
The STA-9 is a Class A+D stereo amplifier. In stereo mode, its power is 120 watts per channel, but it can also work in mono amplifier mode with a power of 290 watts. The amplifier circuit is borrowed from the IDA-8, which is based on a high-impedance class A pre-stage and a Class D power stage. Thanks to this, the novelty sounds "almost lamp-like", but at the same time it is clear and reliable. The 95 dB signal-to-noise ratio is achieved by JFET transistors simulating triodes.
The NuPrime STA-9, a 2 x 120W Class A+D stereo amplifier coupled to a 290W mono amplifier, is designed with an improved even-order harmonic circuit that mimics the most attractive sound characteristics of tube amplifiers without the disadvantages of lamps and limitations. The spacious, transparent, dynamic and luxuriously textured STA9 sound stage must be heard to believe it.