Greg, it appears that something's wrong which isn't directly due to the 3008(unless your unit is defective), since it should be able to easily drive M80s to beyond safe listening levels(as the numbers indicate, and other users have reported). The most common thing when something like this is present is an intermittent short in the connecting wires(or possibly internally in one of the speakers). Re-connect all the wires very carefully even if they appear to be good now. Try using only one M80 at a time to see if possibly an internal short is present in one of them.
