What about the compatibility with Line 6 Headers and another brand cab?   Can I connect the "Line 6 Spider IV 150 HD" into a "Marshall cab 2x12" with regular celestion 8ohm wich is usually used for connect 100W Marshall headers as MG100FX or DSL100H?   I need to know 'cause I'm afraid about burn it out my speakers, I mean, the 150W is not to much power for a regular cab usually used for headers of 100W?  I got a new one and I'm not using it waiting for to know if there are compatibilit