Hello people, 
 
I have a Marshall 4x12 bass cab that I bought with 4 Eminence 16ohm 250watt speakers in that I wanted to run with a pre-amp and power amp, well the power amp bridged at 8 ohms and the Cab was running at 4 so I did some DIY on it and installed 2 jacks in the back so it ran as basically 2 cabs at 8ohms and 500watts each. 
 
the only problem now is the power amp i'm using only runs at 150watts @ 8ohms and i'm really into the idea of getting as much power as I can out of this cab. 
 
I only know a little I've learnt along the way so thought i'd ask some people who know more about this stuff, i'll post a picture of basically what my setup ampwise is. 
 
 
 
please note: where that A/B box is I'm running a Mixer currently to get it up the right strength signal. 
 
Thanks alot. Sean. 
 
Any questions just ask.