Out of the 500 threads a search for "impedance" yielded, I couldn't find my answer. So I pose this question to my fellow TBers. My Trace head (AH250 GP12 SMX) has 2 8 ohm speaker outs. Do these need to see an 8 ohm load? Or is it safe to show them 4. I have to replace subs anyway, but I wanted to know if I need to get 8 ohm for a total imp. of 4; or 16 ohm for a total imp of 8. Also, as they're listed as 8 ohm outs, will running each to a seperate 8 ohm cab result in a 4 ohm load? Which would lead me to believe that showing a single out 4 ohms is safe. Am I on the right path with that thinking? Thanks, ~Steven For clarities sake...I think 8 ohm -------> 4 ohm cab 8 ohm -------> empty yields same results as 8 ohm -------> 8 ohm cab 8 ohm -------> 8 ohm cab does that total to a 4 ohm load? Also Trace/Gibson was helpful enough to send a manual, as I bought the amp used. But it was unable to answer my question.