However, it sounds like what the OP wants to do is just mirror the same signal to the inputs of two separate amps.
Not Quite.
Alright here's the senario:
I've been asked to set up a speaker system in a fast food resturant.
I've been supplied a Small Sony Stereo HIFI, It comes with 2 x 6Ω Speakers and the Minimum output impedance is also 6Ω on the HIFI.
Also, the resturaunt has 2 x 8Ω speakers spaced out in the Front Of House.
It would be simple if all the owner wanted was to use the 2 x 8Ω FOH speakers that are already installed.
But, he also wants to connect the speakers that come with it, and place them in the Back Of House with the steroa so the employees have music out the back.
Still fairly simple,
I could connect the L&R channels up, 1x6Ω and 1x8Ω each, in series (not parallel becasue the impedance would drop to about 3.4Ω and cook the Amp in the Stereo).
But, he wants a switch in the BOH to be able to turn the BOH speakers on and off during store open hours.
Music is only for employees before open and after close when preparing/cleaning up.
This is one senario I have:
But the problem I think will be becasue of the significant impedance changes, this will effect volume.