Прочие устройства — Accuphase PS-550 120 V

The PS-550 is the sixth generation of the compact Accuphase Clean Power Supply range, succeeding the PS-530. The family started in 1996 with the PS-500 and continued through the PS-500V, PS-510, PS-520 and PS-530. This unit is wired for 120V mains, and a 230V build exists for other markets. Instead of passively filtering the wall supply, it rebuilds the AC waveform with analog signal processing, comparing the incoming mains with a clean reference and adding or subtracting the difference.

Key specs that matter

Rated output capacity is 400 VA continuous, while the front meter reads up to 510 VA, the level at which the overload indicator starts to blink. Output waveform total harmonic distortion is guaranteed at 0.08% or less, and the output voltage is held at 120V within 1.5V, or at 230V within 3.0V on the other version. No-load power consumption is 27 W for the 120V build and 43 W for the 230V build. Cooling is natural convection with no fan. The chassis measures 465 mm wide, 181 mm high and 385 mm deep and weighs 24.4 kg. A multi-function liquid crystal display offers seven modes - output power, input voltage, output voltage, input distortion, output distortion, input waveform and output waveform - and it can be switched off.

Engineering and use context

A large high-efficiency toroidal transformer sits at the centre of the chassis with an electrostatic shield between its primary and secondary windings to prevent coupling, backed by two 22,000 uF filter capacitors. The power amplifier block on the right side performs the addition and subtraction for waveform compensation, using a pure complementary push-pull output stage of 10 parallel bipolar transistors for high peak current and low output impedance. The reference signal generator runs the mains through a limiter, a band pass filter, six band eliminate filters and a second band pass filter, which lowers both distortion and noise in the reference. Accuphase shows third-order harmonics of a 50 Hz supply reduced by more than 40 dB at the output. Internal wires to every outlet are cut to equal length, and the power switch doubles as a circuit breaker that trips on overcurrent.

Pairing

The PS-550 capacity fits sources, preamplifiers, integrated amplifiers and moderate power amplifiers, and its height matches a standard Accuphase component shelf. Very large power amplifiers are better served by a unit with more capacity.

Alternatives

The Accuphase PS-1250 is the larger Clean Power Supply of the same generation, with two power amplifier blocks, a color waveform display and a 900 VA rating in its 120V form.