Parasound A 21 Understanding The Indicators On The A, A&B AC Present Indication, Both Illuminated

UNDERSTANDING THE INDICATORS ON THE A 21 10

A&B AC Present Indication

When the A 21 is plugged into a live AC outlet, a soft blue halo glows behind its On-Offbutton and its red “P” Badge glows faintly. These indicate that the unit is plugged into a live AC outlet, even when it is turned off.

BOn, Off and Fault/Protection Status Indicators

Whenever the A 21 is turned on, the soft blue glow behind its On-Off button will change to red for about five seconds as its internal circuits stabilize. Then the red glow is replaced by a brighter blue glow to indicate normal operation. If the glow remains red after turn on or while the amp is playing, it indicates activation of the A 21’s protection circuits and no sound will be heard from the speaker. The A 21 protects itself from external conditions such as excessive heat, load impedance that is too low, or a short-circuited speaker connection or wire. After you correct the fault, the A 21 will resume operation. If the A 21 remains “in protection” after it has cooled down and you’ve confirmed there are no external faults, it could indicate an internal problem. Please contact Parasound’s Technical Service Department.

C&D Left and Right Channel Status Indicators

C&D

C&D

E

These are two small round indicators in the center of the recess in the front panel. The indicator on the left displays the status of the left channel and the indicator on the right displays the status of the right channel.

Both Illuminated

When both channels are operating normally, these both glow blue.

No Illumination:

When the A 21 is turned off, these indicators are off.

High-Temp Indicator

This indicator is near the right side of the panel recess. It will glow red if either channel overheats. The On-Off button will also glow red if the A 21 overheats.

FGain Control Knobs

These adjust the gain (level) of the A 21. We recommend that you rotate the Left and Right Gain controls to their maximum clockwise positions, marked THX Reference. Refer to Gain Controls in Technically Speaking for more information about these adjustments.

GGround Switch

The Ground switch can assist in reducing audible hum caused by ground loops in your

system. This switch should be in its Normal (down) position. If you hear hum you can move it to its Lift (up) position to eliminate it. Refer to the Technically Speaking section for more information about ground loops.

A

A 2

B C DE

F F

G