Problem with sub amp?


I have Tyler Acoustic PD80s with the built in subs/amps. A couple weeks ago after shutting the system down, the subs in the right speaker started humming. I powered up the McIntosh, the hum stopped, I powered down the Mc and 5 seconds later the speaker started humming again. I run single wire to the lower terminals on the speaker then jump from the upper terminals to the high level input on the PDs amp. When the subs hum I can not detect any noise comming from the mids or horns. The problem happens probably 50% of the time. My fear is leaving for work having forgotten to kill the power, that low hum would drive my dog completely insane after 8-10 hours. I suspect it is a problem with the sub amps... any ideas on how to narrow it down?

Thanks
nuguy
Thanks for the replies. The amps are class D, and it's not your typical inherent noise. There is definately a problem. I have not measured the hum, but I am guessing it is achieving 85-90 db. Not enough to do damage to the drivers, but like I said it could drive my dog insane if I ever forgot to switch off the power before leaving for the day.

I did call Ty and of course he will help, although he has never came across this issue. He wants to start with a new amp. I will have to eat the shipping to return the old amp, but I'm sure Ziggy (the dog) will be appreciative.

Thanks again
Loudspeaker produce electricity you are moving a coil in a mag field thus producing AC. Your sub amp sence this as signal so power up.Amps are fine but seems you have a ground loop problem have you tried a cheater plug to remove ground on sub amp power cords?
considering they are brand new designs by tyler why not get them involved? I had humming always when subamps were involved, plate subamps, but not as bad as it seems your describing, but this is sometimes the downfall to having active speakers with amps that kick on and off in a standby function.. if they are A-B amps it seems sometimes these are quieter than the Class D plate amps with hum, weird sometimes.
OK, the problem is in the speaker. I unhooked the speaker from the amp and the hum continues. Here is what's happening... I have the sub amp off (red light on), I can push on either midrange driver, the amp turns on (green light on) and the hum starts, the mudrange speakers vibrate as well. I can put slight pressure on either mid with my finger and the hum quits. It's like the mids are acting as microphones and creating a feedback loop. I can even start the hum by yelling into the mids.

This may sound strange but, here's another example, I can close a door in the house and create enough of an air pressure to move the mids and create enough voltage to trigger the amp. I know this shouldn't happen, but it does. I assume the amp is at fault. Has anybody had a similar experience?