xrandr detects amplifier as monitor

To help with setting up multi-monitor X I'm using a simple to get screen resolution information using xrandr. This was working fine until I tried attaching an amplifier to attempt to use HDMI audio output. Now the xrandr output contains extraneous information about a monitor which is not present. Is there some way to avoid xrandr detecting this device as another monitor? The device is an .

An obvious workaround is to detach the amplifier every time I start X.