Integrated amp + 2 prs speakers

[ifsixwasnin9]

I was told not to use 2 pairs of speakers with an integrated amp and it would burn the amp up I have a Yamaha 100W amp with outputs for 4 speakers.

 

[TLS Guy]

I was told not to use 2 pairs of speakers with an integrated amp and it would burn the amp up I have a Yamaha 100W amp with outputs for 4 speakers.

If it is an old amp with A & B speakers, then you have probably been advised correctly. What is the amp and what are the speakers?