Hello all...I'm a newbie and I admit it. I have home theater system with Onkyo 501 receiver, Bose center speaker, Velodyn subwoofer, older yamaha bookshelf speakers, and Bose 201 using as rear speakers. System sounds pretty good to me even though I realize it is not top of the line...however, my problem is that receiver sporadically turns off when volume is at high level. I have checked speaker connections for short, and do not have any loose strands of wire touching each other or receiver chassis. Speaker wire has been spliced, but is covered with electrical tape at splice. Receiver is set for 6 ohms...there is 4 ohm option. After researching this cite, it seems short is likely problem most people mention, but I do not believe I have short anywhere. Heard someone mention spliced speaker wire may be cause, but is this so if splice is properly covered with elec. tape? Should I try setting receiver to 4 ohm option even though all of my speakers are 6 or 8 ohm? Anyone have any suggestions? What about pre-amp....can pre amp be used on Onkyo receiver, and would this help if receiver is cutting off from being overdriven? Again, hope my questions aren't too dumb..thanks for any help.