I'm guessing expense. Now, I do not do muchy home theater at all so I'm not too sure on the price points of HT amps, but judging from the OP they are esspenssib. //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif
I use a computer power supply and take the main connector and jump connectors I forget which ones they are but if you look at the connector and see the little plastic tab just the conect or right in front of that to the green on I will look for the link and post it but than all i do its strip a yellow wire and black wire and there is your 12 volts. HERE IT IS!!!