PCGU1000+speaker

I would like to generate some sound on PCGU1000. What parameters of the speaker can I use not to damage generator?

To get some sound and not to damage the generator you have to use a high ohm speaker.
Here an example: sciencefirst.com/Speaker-100Ohm-0.2W.html

Please, can I use headphones 60 ohms? Is generator protected against permanent short circuit?

[quote]Please, can I use headphones 60 ohms?[/quote]Yes.

[quote]Is generator protected against permanent short circuit?[/quote]Yes, but not recommended to keep the output short circuited. Internal amplifier heats up a lot.