Accuphase PS-1200 (1997)
High-capacity clean AC power supply designed to deliver stable, low-distortion voltage to audio systems.
Overview
Accuphase Laboratory, Inc. of Japan released the PS-1200 Clean Power Supply in April 1997 as a high-power version of the PS-500. It uses waveform shaping to correct the incoming AC and put out a clean 120V or 230V, with total harmonic distortion of 0.3% or less. It does not regenerate AC from DC. It watches the input waveform all the time and corrects it against an internal sine wave reference, adding or subtracting power as needed. There are 7 AC outlets - 5 on the back and 2 on the front. A central meter shows input/output voltage, distortion, and the power draw of the connected equipment.
Specifications
| Rated output capacity | 1,200 VA (continuous) |
| Rated output voltage | 120V/230V (constant) |
| Instantaneous current supply | 120A/60A (inrush) |
| Output waveform THD | 0.3% or less |
| Input voltage range | 108–132V / 200–253V AC |
| Input frequency | 50Hz/60Hz |
| Input capacity | 1,500 VA (at rated output) |
| Power consumption (no load) | 60W |
| Cooling system | Natural air cooling |
| Dimensions | 475W × 242H × 508D mm |
| Weight | 37.2 kg |
Design
The PS-1200 uses a pure complementary symmetrical circuit with a current feedback amplifier for the waveform correction. The output stage is 20 parallel push-pull transistors, each rated for 16 amperes. Power comes from a super-ring type toroidal transformer rated at 1,500 VA, with the primary and secondary windings fully separated and shielded. The input has a line filter to suppress high-frequency noise, and an AC feedback system keeps the output impedance very low. On the front panel, a selection knob sets the central meter to power draw, voltage, or distortion. The heavy-duty power switch also acts as a circuit protector. Protection circuits cover input current overload, instantaneous output overload, and DC voltage in the output.
Context
The PS-1200 was the large-power variant of the PS-500, with more capacity for high-end audio systems. It aimed to improve system performance with stable, low-distortion AC power, without the inefficiencies of full AC-to-DC-to-AC regeneration.
Market
Originally priced at ¥500,000 in April 1997, the PS-1200 was noted in 2000 as costing over $8,000. A used unit in mint condition was listed for $2,416.80, modified with an internal tap change to accept US voltage and tested at 100V output without issues.
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Service Manuals, Schematics & Catalogs
- Catalog (1991) — archive.org
- Catalog (1992) — archive.org