Усилители для наушников — Nuprime Audio AMG HPA

NuPrime Audio's AMG HPA combines headphone amplification with a line preamplifier and belongs to the AMG series, which also includes the AMG PRA preamplifier and the AMG STA power amplifier. It is priced at USD 1,999. NuPrime describes it as the first headphone amplifier with a 1 MOhm input impedance, a design taken from its EVO ONE amplifiers.

Key specs that matter

The balanced 4.4 mm and four-pin XLR outputs deliver 3,500 mW into 32 ohm and 300 mW into 600 ohm, and the 6.3 mm jack delivers 2,000 mW into 32 ohm and 150 mW into 600 ohm. Headphones down to 8 ohm can be driven. Frequency response is 20 Hz to 200 kHz at -3 dB, THD+N is 0.05%, signal to noise ratio exceeds 100 dB, dynamic range exceeds 80 dB and crosstalk is at least 80 dB at 1 kHz. The input impedance is 1 MOhm from 10 Hz to 200 kHz. Inputs are one XLR pair and three RCA pairs, and the RCA and XLR preamplifier outputs let the unit act as a line preamplifier. It measures 235 x 55 x 300 mm, weighs 2.5 kg, is finished in grey and runs on switchable mains voltages of 90 to 130 V or 210 to 250 V.

Engineering and use context

At its heart is a single-ended Class A amplifier module that runs with no negative feedback. The signal path is fully balanced, with separate circuits for the input, volume control, amplification and output. Volume is handled by two MUSES72320 chips in 100 steps from 0 to 99, a resistor-ladder design that keeps the level control in the analogue domain while allowing precise channel matching. The power supply uses a custom R-core transformer and 26,000 µF of filter capacitance. This input impedance is far higher than the 10 to 50 kOhm of typical amplifiers, which means the source sees an almost negligible load and valve preamplifiers or DACs with high output impedance can drive it without losing level. Balanced outputs deliver higher power than the single-ended jack because each side of the headphone driver has its own amplifier, which doubles the voltage swing. Three RCA inputs plus one XLR input allow several sources to stay connected, and the preamplifier outputs turn the AMG HPA into the control centre of a small speaker system with active monitors or a power amplifier.

Pairing

Planar magnetic and high-impedance headphones benefit from the high balanced output, while the ability to drive very low impedances covers sensitive models. The AMG STA power amplifier connects to the preamplifier outputs for loudspeaker playback within the same series.

Alternatives

The NuPrime DAC-10H combines a DAC with a high-power headphone amplifier in one chassis.