Accuphase PS-550 Clean Power Supply

PS-550 At A Glance

• Rated output: 500 VA continuous
• Output total harmonic distortion: 0.08%
• Topology: Active waveform-shaping AC regeneration with high-grade output-voltage correction
• Front-panel monitoring: Input/output waveform display; output power meter; input/output voltage meters; input/output distortion meters
• Construction: Large high-efficiency toroidal transformer; large filtering capacitors; high-sensitivity protection circuitry
• Outputs: Multiple AC output terminals; available in 120 V and 230 V versions

The PS-550 is Accuphase's 500 VA clean power supply — a full active AC regenerator that takes mains-grade power and rebuilds it into a 0.08 %-distortion, voltage-corrected sine wave that the system's amplifiers and source components see in place of the wall outlet. For mid-power Accuphase systems — an E-3000, E-4000, or E-700 integrated amplifier feeding a pair of mid-tier speakers, or a separates system built around a C-2300 preamplifier and a P-4600 stereo power amplifier — the PS-550 is the right-sized power conditioner.

Active regeneration, not passive filtering. A passive power conditioner attenuates noise on the incoming AC line but accepts whatever waveform shape the line is delivering. An active regenerator does more: it samples the incoming waveform, compares it to a reference sine wave, and synthesizes a clean output by re-shaping the waveform on the fly. The PS-550 holds output total harmonic distortion to 0.08 % regardless of how distorted the incoming mains is — typical residential mains in a developed-world city is in the 2 % to 5 % THD range, and routinely worse during high-load hours.

Voltage correction. Mains voltage at the wall outlet varies — by time of day, by season, by load on the local grid. The PS-550 corrects the output voltage in real time to the unit's rated voltage, holding it stable against the supply-side variation that compromises amplifier bias points and transformer flux margins.

Monitoring at the front panel. The PS-550 carries a row of meters that show the listener what is happening in the AC chain: the input and output waveforms can be displayed for direct visual comparison, output power consumption is metered, input and output voltage are metered separately, and input and output THD are metered separately. The instrument-grade front panel is consistent with Accuphase's signature aesthetic and provides genuine diagnostic information about the system's electrical environment.

Build quality and reliability. The PS-550 uses a large high-efficiency toroidal transformer, generously sized filtering capacitors, and a high-sensitivity protection circuit. The chassis carries the same machined-aluminum construction, brushed-gold faceplate, and high-carbon cast-iron isolator feet as the rest of the Accuphase line.

Sizing notes. The PS-550 is sized for source components and small to mid-power amplifiers. Customers running A-300 monoblocks, an A-80 or A-48S stereo power amplifier, or any of the higher-current Class A integrated amplifiers should consider the larger PS-1250.

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