Warning: Some amps, especially those that are not truly balanced share some parts at the balanced/unbalanced ports. So, while you are using balanced, you might be sending a signal back up the line to the unbalanced components. The switch, in this case, is not designed as a 'cut-off', but more like a router.
If you happen to have both systems on at the same time, you might be in for some serious, big time trouble.
I understand McIntosh would be one case where you must avoid this.
BE CAREFUL!!!!!