Topshelf

Hi evr'one! Am I in the right place here if, say, I have a query regarding whether or not it is safe to run 4 speaker cabs (8ohms ea) off of a power amp which has four 1/4" outs? ??? Am I right in thinking that when you put two 8ohm speakers on ONE side/channel, the 8ohms becomes 4ohms? Any help is thoroughly appreciated :)