Can any stereo amp be bridged to mono ?

I came across some professional audio pdf's when researching a Yamaha P2200 amp. They state this is easily done ( with their amp ) with a splitter transformer on the input with one side out of phase with the other going into each channel; then connecting the speaker to the 2 positives. Would this work with any amp ?
The pdf is at this address - check section 6 page 17
http://www2.yamaha.co.jp/manual/pdf/pa/english/amp/P2201E.pdf

Your expertise required, expected and I am eternally grateful