Усилители мощности стерео — Parasound NC 2250v2

The Parasound NC 2250v2 belongs to the NewClassic series as a two-channel power amplifier, housed in a compact 3U rack-mountable chassis. It uses a high-current Class-AB topology and holds THX Ultra2 certification. Parasound positions it for music and home theater use and cites high current capacity and efficient heat management. The USD 1,500 price is backed by a parts and labor guarantee lasting two years.

Key specs that matter

Per channel, Parasound rates it at 275 W into 8 ohms, and at 400 W into both 4 ohms and 2 ohms, the lower load needing the selector set to its 2 to 3 ohm position. In bridged mono mode it delivers 750 W into either 8 or 4 ohms. Peak current capacity is 45 A per channel. Frequency response is 20 Hz to 50 kHz at plus 0 and minus 3 dB measured at 1 W, and dynamic headroom is 1.6 dB. THD is 0.20% at full output and 0.015% at average listening levels, IM distortion is 0.05%, and transient IM is not measurable. At full rated power, noise is 114 dB below signal IHF A-weighted and 106 dB unweighted, while at 2.828 V the figures are 93 dB and 84 dB. The damping factor is above 150 at 20 Hz.

Engineering and use context

Input impedance is 33 kilohm, and an input of 1 V produces 28.28 V at the output, in line with the THX standard. Rear-mounted gain controls are fitted, as are standby, channel status and temperature indicators. Parasound lists the changes of the v.2 version as a rear lockout switch for the A/B speaker buttons, a more sensitive two-position audio trigger, 12 V trigger jacks moved from 2.5 mm to 3.5 mm, lower standby consumption, revised front and rear styling, power ratings raised by 10 to 15% on average and removal of the ground lift switch. Crosstalk measures 85 dB at 1 kHz, 73 dB at 10 kHz and 67 dB at 20 kHz. Protection relies on DC servo and relay circuits. A rear selector sets the mains input to 110 to 120 V or 220 to 240 V at 50 to 60 Hz. Power draw is 0.5 W in standby, 35 W at idle with no audio and 1,000 W at full output. The chassis is 437 mm wide and 470 mm deep with cables, 153 mm tall with feet or 133 mm for the panel alone, and weighs 19.5 kg. The optional RMK33 kit allows rack mounting.

Pairing

Line-level sources connect through gold-plated RCA input jacks. The amplifier turns on from a trigger signal at 9 to 12 V and 15 mA, or by sensing audio, with thresholds of 1 mV and 6 mV. Dual A and B speaker outputs with a lockout switch let it drive two pairs of speakers, and a switchable high-pass filter, sloping at 18 dB per octave, at one of two frequencies can be engaged for smaller speakers.

Alternatives

The Parasound NC 2125v2 is a smaller 2U NewClassic stereo power amplifier.