I was showing off my mark IV to a friend, who always wanted a mark IV but never played one (wierd I know), I brought it to his house and used is ampeg cab with a combo of v-30's and some unkown peavey speaker. I used his low end ibanez with active pups and was immediately embarrased. He looked at me with dissapointment. I was like dude something isnt right, went over all the knobs again changed the batteries in the pups as well and played. I couldnt believe how much different it sounded with his cab/guitar. I got back to my house plugged it back into my recto 2x12 and bam!!!!! The differece was night and day. Goes to show how one weak link can ruin even the best of amps. BTW this amps is amazing for santanaesque tones!!!!!!!!!!!!!