Quote Originally Posted by Чайковская
'amplifier'
Yes we use 'усилитель' for 'amplifier' in most cases as well as for an electric guitar amplifier.

Quote Originally Posted by Чайковская
'Rink Guard'
Whereas I used to skate outside I've never met any rink guards here. Though we would call them "сотрудники катка" (or "работники катка") "people who are in charge (who work) at the ice-rink".