What I'm workin with ... I have an OLD trace elliot AH150 (12 band eq) with no users manual. There are two speaker outs on the rear with the words "Total Load 4 OHMS". I have two cabs available to me. One is an old Fender BXR115 (Impedance 8 OHMS - Power Rating 150 watts) but I am told the original speaker has been replaced with a 15" Peavey Black Widow. The other cab is a brand new Ampeg SVT-410HLF (Impedance 4 OHMS - Power Rating 500w RMS / 1000w Program). Questions .... Can I use both? Should I use both? Oh you say I shouldn't? Why not? What will happen? Should I get a new head! If so what do I need in order to use both cabs? If you couldn't tell, I am am looking for an excuse to get a new head! Like I said the Trace I have is OLD and beat ..... and since I am still not happy with the sound when cranked with the new Ampeg cab alone, I am kinda thinking it's the head that needs to be replaced. From what I have read I kinda got the impression that running both cabs wouldn't be a good idea but I was wondering if doing so would damage the head or the cabs? or both?!?! Thanks in advance to anyone kind enuff to reply.