The calibrated playing weight marks were accurate and sidethrust compensation was close enough for practical purposes. With the overhang set using the gauge accessory, tracking error was never more than I.5°. I tried an assortment of good quality cartridges and found the adjustments, including arm height, to be no trouble at all. The mains lead is a plug-in type and for the UK it is a three-wire cable with the latest colour coding. The twin signal leads are of low capacitance, to permit use with CD-4 type cartridges, and terminate in phono plugs.
The instruction book is beautifully clear and, apart from mounting a cartridge into the headshell which is always a fiddling operation, the unit can be set up and working in a very short time. The turntable mat is of butyl rubber, claimed to have good anti-vibration properties, and has a removable plastic protecting sheet. The headshell has the now common bayonet connection and the overhang can be adjusted in slots and checked on a plastic gauge. Cartridges weighing between 4 and 14.5 grams can be used and playing weight and sidethrust compensation are easily set. A separate weight gives approximate lateral balance. It is S-shaped, with the offset angle calculated for minimum tracking error and to bring the stylus directly on to the axial line through the counterbalance carrying rod. The pickup arm has precision angular bearings in the vertical and horizontal planes. The clear plastic-cover has push-on friction hinges which support it at any convenient angle. The main plinth block is of dense chipboard, walnut veneered, with insulating feet which can be rotated for final levelling of the turntable. All operation is manual, so that one must place the pickup over the required portion of the record by hand, and lift it back to the rest afterwards. A further move to 'down' lowers the pickup gently on to the record. Moving this from 'off' to 'on/up' starts the motor and illuminates the stroboscope, but keeps the pickup arm raised. A single very convenient three-position control-lever is used. Despite this, it reaches the proper speed in less than one revolution. On my scales it weighed a substantial 2.15kg (4-3/4 lb). The platter is larger than usual, being 324mm in diameter by 25mm deep and is quoted as having a moment of inertia of 340kg/cm2. Then a conventional sub-oscillator supplies the drive frequency and has adjustment over a range of ☖%, equivalent to a semi tone up or down. If it is desired to play records at a non-standard speed, perhaps to bring the musical pitch into line with a piano or other home instrument, the quartz lock button is released. Therefore the strobe pattern remains rock steady even with record cleaner or pickup drag forces up to 120 grams. In normal use, a 'quartz lock' button is depressed to bring the phase locked loop (PLL) speed control circuit into play. A pulse width control circuit shapes the strobe waveform for maximum clarity of pattern illumination. The latter is bidirectional so that torque may be either increased or decreased to ensure rapid realignment in the event of transient interference in the mains supply, speed selection switching etc.Ī separate frequency divider circuit flashes the stroboscope light and, of course, it has been possible to use a single broad stroboscope pattern on the periphery of the platter since the flashing speed changes according to whether 33-1/3 or 45 rpm has been selected.
Any difference produces a correction signal which is applied to the drive circuit. The crystal oscillator frequency is 3.072MHz and this is first divided down to 6kHz before feeding the 33-1/3 or 45 rpm speed selection unit whose output is compared in both phase and frequency with a signal generated by magnetic pulse detection of the rotational speed of the motor itself. A quartz crystal is used to provide the source of constant speed drive, regardless of temperature or mains voltage and frequency. In the present Pioneer model, every feature has been designed for performance rather than economy and so the overall price seems reasonable enough. We have come to associate the direct-drive principle with higher costs, though there are signs that this need not always be so. Now stepping into the top of the Pioneer range is this PL-550 direct-drive model with a price tag about three times that of the aforementioned popular units. THE Pioneer Electronic Corporation of Japan market a very wide range of audio equipment and, while I do not think that they make a specialty of turntable units, they certainly set all their competitors a difficult task of trying to rival the enormous sales of their low cost/high performance PL-12D model.
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