I have a Trace Elliot V Type head and have it connected to an 8 ohm 4x10 cab. I tried to put a 1x15 8 ohm cab as well an d when plugging it, with amp on standby, got a horrible cross between a shriek and buzz. I unplugged it immediately, and amp worked fine with the 4x10 alone. The amp says minimum 4 ohm cabs, so wonder what happened? Needless to say, not going to attempt it anytime soon.