The theft happened Thursday in Lawndale.
The man says he heard noises outside his apartment, went out and yelled at the two men, but they kept doing what they were doing.
Within five minutes, his converter was gone and so were they.
He filed a report with the Los Angeles County Sheriff's Department, who tell Eyewitness News they've seen an increase in such thefts lately.
So far, no arrests on this one.