Accuphase PS-500 (1996)

Name: Accuphase PS-500
Brand: Accuphase

AC voltage stabilizer released in March 1996 with 500 VA capacity and waveform shaping technology

Overview

The Accuphase PS-500 is an AC voltage stabilizer that delivers clean, regulated power to audio equipment. Accuphase Laboratory, Inc. - originally Kensonic Laboratory, Inc. - released it in March 1996 with a rated output capacity of 500 VA. It uses a unique waveform shaping technology. A control circuit adds and subtracts voltage to correct the input AC, then the unit outputs a high-precision sinusoidal waveform synchronized to the input frequency.

Specifications

Product	Accuphase PS-500
Type	AC voltage stabilizer / Clean Power Supply
Release Date	March 1996
Original Price	¥300,000
Rated Output Capacity	500 VA (continuous)
Rated Output Voltage	100 VAC ± 2 V
Rated Output Current	5A
Output Frequency	50Hz/60Hz (synchronized with input)
Instantaneous Current Supply	70A
THD (Output Waveform)	0.3% or less
Input Voltage Range	90 VAC ~ 110 V
Input Frequency	50Hz/60Hz
Input Capacity	750 VA (at rated output)
No-Load Power Consumption	55W
Cooling	Natural air cooling
Dimensions	475 mm (W) × 180 mm (H) × 378.5 mm (D)
Weight	21.8 kg
Outputs	5 AC outlets
Metering	Output power (VA), input/output voltage, input/output distortion factor

Design

The PS-500 generates its sinusoidal output with waveform shaping technology and no internal oscillator. The output is synchronized with the input frequency. A control circuit adds and subtracts voltage from the input AC, producing a compensation waveform of up to ±10 V. The power amplifier stage is a pure complimentary symmetrical circuit with current feedback. It uses 10 parallel complimentary push-pull transistors rated at 10A max. A super-ring type toroidal transformer (approx. 750 VA) provides power, and an AC feedback system keeps output impedance very low. The input has a line filter for high-frequency noise reduction. Protection circuits activate if the load exceeds 500 VA, input current exceeds 7.5A, the output is short-circuited, DC appears, or output exceeds AC108V. A 70A current limiter handles inrush currents.