The best means of doing this is to utilize a high quality distribtion amplifier. You can obtain these anywhere from the price range of a few hundred dollars to well over a grand. Companies/products to look at include ATI (http://www.atiguys.com), Aphex and Henry Engineering. Look at the specifications to get the best bang for the buck.

what about a small mixer with subouts?

X

Many thanks Alex, I'm going to research. So many choices. I need some time to compare.

Xrocka, small and affordable mixer(s) (I have two) usually color the sound too much and does not handle balanced +4 signal very well. But thanks anyway for the input.

if both destinations are high imp bridging inputs
and the output is genuine 600 ohm

then it is very possible that a passive Y cord approach may do what you want.

one of sites has some notes on this
http://www.diyfactory.com/projects/dawmonswitch/dawmonswitch_1.htm

Thanks Kev,

I'm on the way to check that.