hi all. I tend to pick up alot of stereo stuff when I figure the price is right "the wife says I have problem heheh" I am not savvy to all the technical stuff on the insides I just love great sounding music so please bear with me. I have a set of infinity kappa 8's that I'm having a hard time driving. I have a hafler xl600 that I picked up years ago and its been sitting collecting dust that I figured would drive them effortlessly but when I try to push them at over half throttle the woofers distort and sound like crap. so I then pulled out a hafler dh 220 that has also been collecting dust and I tried the bi-amp route. used the dh 220 to power the high's left and right and the xl600 to power the lows left and right and figured this setup should sing! NOPE same problem horrible distortion on the lows when trying to push it over half throttle. so I hooked them up to my NAD-C-375BEE and they sound pretty dam good but you can tell they need more juice but if i flip the switch on the speakers into extended mode the NAD cant handle it when I turn it up and shuts down into safe mode. if i have the NAD hooked up to my klipsch ref3 II speakers I can go over half throttle no problem and it sounds wickedly wonderful. this hafler xl600 is supposed to be the wholy grail and beast from what I've read but not impressed at all. I'm thinking maybe the hafler xl600 has something wrong with it? any thoughts? also I know some are going to say why do I need to turn it up over half, I dont allways listen to it that loud but sometimes... well you know heheh. besides if its too loud your probly too old?