Pioneer PL-51A (1974)

A direct-drive turntable for stereo, quad, and CD-4 records, with a dynamically balanced platter and a low-noise motor.

Overview

The Pioneer PL-51A is a high-fidelity turntable made in 1974. It is the Japanese-market name for the Pioneer PL-1200A. It was built for people playing advanced formats like CD-4, Quad, and SQ records. The tonearm is a static-balance S-shape, set up for lightweight cartridges such as the Shure V15. The platter is a 31 cm aluminium alloy diecast, dynamically balanced, and it's turned by an ultra-slow running brushless DC servo motor. Pitch control has stroboscopic calibration accurate to ±2%. The LSC (Low Stray Capacity) output cables keep high-frequency response up to 40 kHz, which the quadraphonic discs need.

Specifications

Motor	Brush-less DC servo motor
Drive type	Direct-drive
Platter	31 cm aluminium alloy diecast
Speeds	33 1/3 & 45rpm
Wow & Flutter	0.05% WRMS (FG measured)
S/N ratio	58 dB (DIN-B)
Tonearm type	static balance S-shape
Effective length	221 mm (22.1 cm)
Overhang	15.5 mm
Tracking force range	0...3g
Cartridge weight range	4...14g
Componentry	12 transistors 19 diodes
Power consumption	5.2W max.
Dimensions	48 x 18.5 x 41.5 cm
Weight	10.5 kg

Design

The PL-51A sits on a two-density base with large insulators to isolate it from outside vibration. The tonearm handles lightweight cartridges and advanced disc formats, including CD-4 and quadraphonic records. The platter is dynamically balanced for minimal runout. The brushless DC servo motor holds speed steady with ultra-low wow and flutter. The LSC output cables reduce stray capacitance, which keeps the high-frequency detail on demanding formats. Pitch is calibrated by stroboscope and adjusts within ±2%.

Context

The PL-51A was the Japanese-market name for the PL-1200A. Both were slightly updated versions of the 1972 PL-51 and PL-1200. Released in 1974, it was aimed at users who wanted high accuracy and compatibility with the new quadraphonic and stereo-quad (SQ) vinyl formats.

Market

Original price for the PL-51A was 51,000 ¥ in 1974. Maintenance notes say the electrolytic capacitors are the same ones used in the PL-1400 (and PL-71). Some owners upgrade the main power supply capacitor to 1000uF for improved performance.