Yammy,
The easiest way to do it is to use a Jensen balanced to SE trafo at the input, designed for 40K loading.
You would need to redesign the amp with a fair amount of chopping and changing on the pcb to make it work any other way.
The advantage of the trafo is that it would completely galvanically isolate the amps from the source, which is great for hum issues, particularly if you run multichannel HE sources.
There is no advantage in running balanced lines for a domestic hifi system, though there may be advantages for a HE system, or a pro-audio system, particularly in sound reinforcement where induced noise can be a major issue.
The balanced system tends to knock out even order distortion, no bad thing, which reduces the overal THD of the system.
However, it does nothing for the odd order distortion, when then predominates.
Hope this helps with your options,
Cheers,
Hugh
