Suggestions/experience with a speaker/headphone switching/output box...

That may not be the best worded headline, but I have a Magnum Dynalab receiver without a headphone output.  Any experience/suggestion on a selector box that would allow a headphone output and a speaker output that would not degrade the sound.  Basically wanting to listen to one or the other and not both at the same time.  Thanks for your thoughts/experience. 

I’d think if you hook a headphone amp (with a volume control) to the fixed preouts on the receiver that’d work.  When listening to headphones just turn the volume all the way down on the receiver, and when you want to listen to speakers only just turn the headphone amp off.  Hope this helps.