I am using a Mesa M-Pulse 360 http://www.mesaboogie.com/Product_Info/Bass_Amps/M-Pulse360/M-Pulse-360.html When i run it, I run it through the Line out not the speaker output. Always run it through a combo. My tubes just blew 2 days ago and I'm still scratching my head why it blew. Don't need any consolation just enlightenment. Why?