Can I use powered speakers with a portable headphone amp/dac?

[AstroBenny]

So I recently bought a Fiio Q1 to use with my DT770 80 Ohms but also happen to have a pair of M-Audio AV40s speakers for casual listening use. When I plug the Speakers in to the Fiio there is a high pitched whining sound which is quite audible. Am I better off just using the mobo to power the speakers? The Q1 also has both a line input/output as well as a headphone jack. When would the line input/output be used? Cheers

 

[Volbet]

Well, the line output would be used with powered speakers, since you're connecting the Q1 to an aleady amped pair of speakers. 

The line out circumvents the Q1's amp and just outputs line volume. That means that you can't use the Q1's volume control, so you have to rely on your speakers or Windows for volume control.