OK, I have and SVT 3 Pro, Ampeg 410E, and Avatar B115H. The Ampeg is an older one, 8 ohms, 200 watts I believe. The Avatar is 8 ohms, 500 watts? Svt 3 Pro runs at 4 or 8 ohm. I connected both the 1/4" jacks in the head to each cab, and only the Avatar will work when I do this. Why? It recommends in the manual to use a speakon cable when running with a full load, but should the regular 1/4" jacks work when both are connected or not? Either cab works fine when connected by itself. So do I just need to get a speakon to 1/4", or is there something wrong?