Audio Systems: feedback from sub hookup, yamaha rx 750, watt speakers

Question
Hi, I`m having a small problem taking care of and diagnosing a feedback issue,power on or off. I have an older Yamaha rx 750 receiver, a pair of Paradigm 9se (150 watt) speakers running thru a DCM KX-1 sub. This is my issue---when plugging in my sub (secure line) I got this insane amount of feeback thru my speakers whether my power was on or off however I cleared up the problem by using a "cheater plug" (no ground) into my outlet and everything works just fine---except---now when not in use for a while then I turn on stereo the sub will not work at all but if I unplug the sub & let it sit a few mins with the power "on" and plug it in again it works fine till I turn off the sub power whenever I finish listening and then I have to redo the unplug thing again. My system works & sounds just fine after the unplugging & replugging of the sub-----any hints on what I`m doing wrong cause unplugging is getting to be kinda tiresome --thanx

Answer
Do you have the manual for the DCM KX-1?  You should read through it - only 4 pages.  It explains the turning ON feature of this sub;  it has a sensing circuit that will turn on the sub when an audio signal is sensed.  Likewise it will turn itself off when it does not sense an incoming audio signal at the inputs.

And, you must follow a certain procedure when first hooking it up to an audio system.  So, again, you must study the owners manual and follow the prescribed procedure.

If the above does not solve the problem you will need to have it checked out by an audio shop as there is likely an electronic problem inside the DCM KX-1 unit itself.

The manual for this is at:

http://www.retrevo.com/search/v2/jsp/mytrevo/myTrevo.jsp?page=man

Hope this helps.