Усилители мощности моно — Nagra Reference AMP

The Reference AMP is a monoblock power amplifier from Nagra, the Swiss company founded in 1951 and known for its portable tape recorders and high-end audio. It replaces the HD AMP, originally designed about ten years earlier, and was designed in parallel with the Reference PREAMP. Together with the Reference DAC, it forms Nagra's Reference line.

Key specs that matter

Each monoblock uses a new 2,000 VA transformer, potted in epoxy, and a power supply 25% larger than the HD AMP's. Nagra rates it at 300 W RMS into 8 ohms, with 30 W of that in pure Class A, rising to as much as 1,000 W RMS into lower loads. Bandwidth is 0 Hz to 120 kHz (+0/-0.5 dB), THD+N stays below 0.03% and typical signal-to-noise reaches 110 dB (A-weighted). XLR and RCA inputs have 88 kohm and 44 kohm impedance, with 1 V or 2 V sensitivity. Each unit is 23.8 cm wide, 64.4 cm high and 54.2 cm deep, at 56 kg. Speaker terminals are WBT Next-Gen. The outputs have two damping factor settings, A and B.

Engineering and use context

The input circuit is new, with a very low output impedance to drive the amplifier stage. Extending the Class A region means the output devices stay in Class A up to a higher output level before moving to Class AB, keeping more of normal listening free of crossover distortion. Potting the transformer in epoxy reduces mechanical vibration and radiated hum. Internal three-stage mechanical damping quiets the vibration of key parts, and adjustable resonance-decoupling feet combine phenolic material with pure copper. The internal line and speaker cables are sourced from a high-end cable manufacturer and chosen by listening. The two damping factor outputs change the amplifier's output impedance seen by the speaker. The A setting, with lower damping, lets the woofer move more freely and extends the bass, while the B setting controls the woofer more tightly, useful in rooms that reinforce bass or with speakers that need firmer control. The casework was changed to match the Reference line, including Nagra's chamfering and a Reference medallion on the front. Like other Nagra amplifiers, it carries a front-panel modulometer that shows output level. Nagra states that hundreds of hours of listening sessions shaped the final design.

Pairing

The Reference AMP is designed to pair with the Nagra Reference PREAMP. The damping factor selection helps it match speakers with different bass alignments.

Alternatives

Nagra's HD AMP is the previous monoblock on which the Reference AMP is based.