Apple Desktop Computer manual Sound Specifications, External Sound Output, Headphone Jacks

C H A P T E R 3

Devices and Ports

■during power cycling

External Sound Output

The external sound output jack is a 3.5-mm mini phone jack located in the I/O bay on the right side of the computer. It accepts a stereo miniplug-to-RCA cable adapter for connecting stereo equipment to the computer.

The sound output jack has the following electrical characteristics:

■output impedance: nominal 180 ohms

■maximum level: nominal 1 V rms (2.8 V peak-to-peak)

Headphone Jacks

Two headphone jacks are located on the front of the computer next to the right speaker. Each sound output jack provides enough current to drive a pair of low-impedance headphones.

The headphone jacks have the following electrical characteristics:

■output impedance: nominal 13 ohms

■maximum level: 1.4 V rms (4.0 V peak-to-peak)

Headphones should have an impedance not lower than the recommended minimum impedance of 32 ohms. Headphones with lower impedance can be used, but with some degradation in performance.

Sound Specifications

The frequency response of the sound circuits, not including the microphone and speakers, is within plus or minus 1 dB from 4 Hz to 20 kHz.

Sound System 37