Last week, my band played a gig outdoors and everything sounded great. I set my Carvin R600 amp on full range and ran one amp to my 8ohm 4x10 cabinet for use as a stage monitor and the other I ran into my Palmer speaker simulator (also an 8 ohm load) at a modest volume and then out to the board. Now, I find that when I plug my cabinet into the "Hi Frequency" output of my Carvin head, I get underpowered, distorted tone that fades in and out. The "Low Frequency" out works fine, as do both the "Bridged" outs. Is it possible that I fried the "hi frequency" amp (the r600 has 2 amps in it) by running it into the dummy load of the Palmer? Again, everything at the gig sounded great, both the sound thru the Palmer and off the board and the sound coming out of my 4x10 stage monitor. Any thoughts would be appreciated.