I need help. I dont play bass but my mate needs a head. He already has a Ashdown MAG 300h head and has a 4x10 cab and a 2x10 cab. I'm not sure on the power of these but there quite powerfull. The MAG head we found out after trying it out isnt powerful enough to power them, its really quiet. So now he's after a new head. At first I was thinking its because of the impedance that its so quiet, beacause the head is 300watt at 4ohm but when powering a 8ohm cab its becomes 150w. But after looking around the net i'm not so sure, I am I right that he's going to have to buy a really powerfull head somthing that runs at like 900watt at 4ohms? If somone can help that would be great, and any head recomendations would but good too. thanks. jon.