amp stays on for 1 or 2 mins after locking car

[Blozz]

hey guys i have a 2011 omega series 2 ute and i had my amp installed professionally today, it sounds great and is hooked up through the high level inputs on the amp....
for some reason the amp stays on until i lock the car and watch it for about 2 mins before the lights go blank... is this normal on VE's? the guy who installed it said its nothing to worry about but i'd rather be safe than sorry, dont wanna be buying a new battery every few days
any information on this would help greatly

 

[07GTS]

will be fine because u have to use the high lever inputs to turn it on and off it waits a while and if it dosnt sense any speaker signal it will turn off, then when it senses speaker signal again it will turn back on, it waits a couple mins cos u dont want it to turn on and off all the time when changing songs ect so it has the delay built in

 

[Blozz]

thanks for the reply mate its much appreciated