I'm playing a Marshall 2554 Silver Jubilee 1x12 combo. I'd like to use the D.I. output on the back panel to run straight into a mixing board... BUT, I'd like to have the 2554 silent (i.e. shut off the speaker). I thought about simply unplugging the speaker, but the owner's manual clearly says not to do this. Anyone have any suggestions for running in stealth mode?