How Does a CD Changer Work?

By Ma Wen Jie

How Does a CD Changer Work?
i Photo: Daniel Wildman, stock.xchng

Cartridge Changers

Cartridge CD changers are often found in cars. In a cartridge CD changer, between six and twelve CDs are slipped into a cartridge. The cartridge is then inserted into a CD changer. A rod in the CD changer moves to the desired CD and slides into the cartridge activating a mechanism inside the cartridge. The mechanism moves a CD to the player mechanism where it is aligned with the center spindle and laser reader.

When a new CD is needed, the one playing is stopped and pushed back in to the cartridge. The push-rod mechanism moves to the next CD and activates the mechanism to remove the CD from the cartridge.

Cartridge CD changers are popular in cars because the cartridges can be easily removed to change CDs. The cartridges provide excellent protection for the discs. Multiple cartridges can be loaded and easily slipped in to the CD changer.

Horizontal Carousel Changers

Horizontal carousel changers are usually found in home stereo changers. They can usually hold 3, 5 or 7 CDs. To load a horizontal carousel changer, each CD is placed face down on a rotating carousel. The carousel spins to place a disc over the playing mechanism. The playing mechanism rises to engage, spin and read the disc.

To play the next disc, the playing mechanism lowers and the carousel rotates to the desired CD. The mechanism raises and engages the new disc.

Because the discs are placed loosely in 5-disc carousel changers, they are best-suited for home stereo installations.

Vertical Carousel Changers

Vertical carousel changers can hold up to 100 CDs. Each CD is slipped in to a vertical slot of a rotating carousel. In these changers, the CD player mechanism is also vertical. When the desired CD is played, an arm rolls the CD into a mechanism that holds the CD. The CD drive assembly clamps the CD to a spindle that passes through the hole in the CD. The CD is raised and aligned with the playing mechanism and the CD begins to play.

To change CDs, the existing CD is lowered to the player cradle and rolled back in to the carousel. The carousel rotates until the desired CD is in position to be rolled in to the CD player mechanism. The arm then rolls the CD to the appropriate position and the CD is clamped and played.

Because the CDs sit loosely in the carousel vertical carousel changers are best suited for home stereo use. If a CD rolls out of position, the carousel can jam.