The pursuit of stable performance led to Philips' development of the single-beam swing arm system. Imposing a couterweight (balancing weight) on the side facing the optical lens block enables the system to adjust the weight distribution and move the optical system usigin relatively minimal power. It also facilitated increased structural precision and, perhaps even more importantly, allowed overall movement to be controlled using highly versatile analog servo circuitry. CDs are irradiated with a 780nm red laser beam from the polycarbonate resin substrate side, and whether the digital data is "0" or "1" is determined by an increase or decrease in the reflection of the laser beam. Thus, extremely accurate optical technology (lens design, lens fabrication, special coatings, and precise assembly) is required for the small optical pickup block.
The first Philips 3-beam linear tracking drive mechanism used by Marantz was the Philips CDM12.1. The Philips VAM1252, equipped with a die-cast body and commonly know as the CD Pro, was employed in the high-en Marantz CD-7. The low cost Philips VAM12 version of the Philips VAM1252 was used in the Marantz CD-17Da and Marantz CD-19a. The Philips VAM2200 series, which may be the last Philips-made CD-only drive mechanism, was used in the laters Marantsz CD-only player, the Marantz CD-7300 (2002).