Ten years after the revolution.
In 1966, Sony brought you the world's first commercially available turntable with a DC servo motor. This effectively slowed motor speeds from 1800 to 300 RPM, producing the lowest rumble figures measured till then.
The servo system also drastically reduced wow and flutter, thus giving you a chance to hear what 33-1/3 records sound like at 33-1/3. Quite a revolution.
But we haven't been sitting on our laurels since then.
Introducing the PS-4750. Overlooking the fact that the PS-4750 is so pretty we could sell it through interior decorators, here are its technical innovations.
It has a direct drive servo motor that gives you incredibly low rumble, wow and flutter levels.
Plus total immunity from line voltage and frequency variations.
That's because the PS-4750 has a unique system that, in essence, 1975 consists of a sensitive magnetic head (with eight gaps instead of the normal one) which monitors platter speed by nicking up a magnetic coating on the outer side of the platter. This speed data goes through a small computer connected to tie motor, instantly compensating for variations.
The PS-4750 is also ultra insensitive to outside vibrations (which causes intermodulation distortion and acoustic feedback). Sensitivity to outside vibration shows as "Q” And the PS-4750 has a platter and case made of SBMC, a Sony developed compound which has one third the "Q" of aluminum or zinc.
We've even done something about the resonance caused by wit pin in the record itself. Those round doo-hickies on the platter are rubber suction cups that actually provide greater contact surface, reducing the longitudinal vibration caused by warp. The end result is a cleaner sound.
So, all in all, our engineers think the PS-4750 is pretty nifty. But don't take our word for it. Just stop into your Sony dealer and show your independence by listening for yourself.
Sony Corp of America Sony, 9 W. 57 St. N.Y., N.Y. 10019.
SONY is a trademark of Sony Corp.
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(High Fidelity, Jan. 1976)
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