Could something be wrong with one cab (or a speakercable?)
Maybe if you daisy chain it, that might work better?
Normally it would go louder.
If the head is working fine with one cab, I would doubt something is wrong with the head.
>> but I'm no technical wonder so my knowledge ends here...
I know this is an old thread but providing this update since it may benefit someone. The SVT212-AV cab is a 4ohm cab so should be plugged into the 4ohm output. If you add a second cab, they need to be plugged into the 2ohm output(s). I jammed for hours this past weekend and didn't realize I had plugged one SVT212-AV into the 8 ohm jack. I couldnt figure out why the amp sounded thin to me. All seems well so I think I was lucky there was no damage. So the OP was running with an impedance mismatch that he made worse when he added the second cab.
