How do I interpret the red power light on the A33? 

There are several reasons for the red power light on the top of the unit to be illuminated.  Here's how to interpret these signals:

Power light is solid red 

• Normal case when the AC adapter is connected and the battery is charging.  The light will go off when the battery is fully charged. 

Power light fades to red, on and off, while the unit is playing 

• Normal case when the battery is almost discharged.  
• The A33 will continue a short time after the red light first starts showing.  If the adapter is not connected, the unit will power off; or in some cases, the audio may stop and start before shutting down completely. 

Power light may flash red intermittently on loud music with heavy bass 

• This is an indication that the battery temporarily does not have sufficient power to support the volume level.  It is most likely as the battery reaches the discharge state.  It can also occur as the battery ages and the full charge is not as high .  In some cases the A33 may actually power OFF in this situation. 
• The A33 battery should be recharged using the AC adapter. 
• Lowering the volume slightly will prolong the battery charge.  See information on playtime. 
• Operating the A33 with the AC adapter should avoid the red indicator when operating at maximum volume. 
• For an older unit, the battery may need to be replaced.