Disc Players

In practice almost all CD transports employ a 'top-loading' mechanism of some description with the laser reading upwards from beneath the spinning disc. The principle variation lies in how the disc is deposited onto the motor spindle, whether dropped in place via a traditional CD tray, drawn in via a slot-loader or, as here, placed manually from above. Exceptions are rare but include the exotic VRDS mechanism developed by TEAC in 1989 – this forced the CD up against the underside of a slightly concaved turntable, precisely centering and damping the disc across its surface while driving it from above. Then there was the superb 'Stable Platter Mechanism' introduced by Pioneer in 1992, supporting the CD (label-side down) on a rubber-coated turntable while reading its silver surface from above.

These exotic variations aside, in almost every type of CD/DVD/ROM drive the audio or data disc is held securely in position by, typically, a lightweight magnetic clamp on the end of a spring-loaded arm, preventing the disc from spinning off the spindle. Manual top-loaders, like the EMC 1 MKV, also use a magnetic puck that squeezes the disc tight onto the motor spindle, although Electrocompaniet has gone a stage further with its optional 'spider clamp' [pictured, above]. This lightweight, magnetic clamp also damps down vibrations at the edge of the rapidly spinning disc, easing the burden on the laser focus servo and subsequent decoding/error-correction. That's the theory at least... PM