Усилители мощности стерео — Mark Levinson № 5302

The No 5302 is a dual-monaural stereo power amplifier from Mark Levinson, part of the expanded 5000 Series, which began shipping in October 2020 at a price of USD 9,000. The company describes it as fully discrete and direct-coupled, working in class AB, and states that its engineering and precision assembly are done in the USA.

Key specs that matter

In stereo mode it is rated at 135 W per channel into 8 ohms and 270 W per channel into 4 ohms from 20 Hz to 20 kHz, and it remains stable into 2 ohm loads. Bridged for mono, it delivers 275 W into 8 ohms or 550 W into 4 ohms. Stereo gain is 25.8 dB, and an input of 145 mV RMS produces 2.83 V RMS at the output. Distortion is below 0.04 percent at 1 kHz and full rated power, and signal-to-noise ratio exceeds 102 dB unweighted. The response is flat within 0.35 dB across the audio band and reaches from under 2 Hz to 80 kHz at the minus 3 dB points. Input impedance is 100 kilohm balanced and 50 kilohm on RCA. The unit is 145 mm high, 438 mm wide and 457 mm deep, and weighs 31.7 kg.

Engineering and use context

Both channels draw power from an oversized 1100 VA toroidal transformer with separate secondary windings for left and right. The voltage gain stage uses a topology taken from the No 534 amplifier, followed by an output stage with two high-speed driver transistors in class A and six 260 V, 15 A output transistors. Two Thermal-Trak devices keep output bias stable whatever the load or temperature, and four 10,000 microfarad capacitors per channel sit directly on the output stage board. Control ports include Ethernet, USB, RS-232, an IR input plus a 12 V trigger in and out, while setup, configuration transfer and firmware updates are done through a built-in web page from a PC browser. Maximum power draw is 1000 W, with 90 W at idle in stereo and under 0.4 W in green standby. The front panel, fitted with a light ring around the standby button, is 25 mm thick anodized aluminium around a glass display.

Pairing

Every channel has an XLR input and an RCA input, so balanced and single-ended preamplifiers both connect directly. Two pairs of high-current multi-way terminals are fitted for loudspeaker cables, and two units bridged in mono form a higher-power system. The trigger input links it with a preamplifier for switching on together. Bridged operation raises gain to 31.8 dB, lowers sensitivity to 73 mV and raises signal-to-noise ratio above 105 dB. Depth grows to 527 mm with handles and terminals, and an aluminium IR remote is included.

Alternatives

The Mark Levinson No 534 is a dual-monaural stereo power amplifier whose voltage gain stage served as the basis for this design.