Is it safe

Wilson667, the guys here are full os s$$$ re. answering your question - it should be OK for you to connect both sources to the Jolida jd502p PROVIDED ONLY ONE SOURCE IS SWITCHED ON AT ANY TIME & THE OTHER SOURCE IS SWITCHED OFF i.e. OFF OFF/COMPLETELY OFF.
The output stage of any component is designed to handle source/sink or push/pull current of fairly large amplitude and the output voltage spec is usually 2V for many line-stage components. So, for an SWITCHED OFF component to see upto 2V on its output stage should be no issue at all - it would be a voltage within spec. Also, there is NO back flow of current into the switched off component because it's off! Current flows only when the 2nd source is powered on & the transistors inside are biased on. When the 2nd source is powered off, the transistors are biased off i.e. they do not draw any current except for some leakage current in the mirco-amps region.
All of this assumes that you will be very diligent in ensuring that only one source is switched/powered on at any one time.

03-15-12: Elizabeth
Thanks for the great clarification Almarg.
And, as usual..LOL! bombaywalla is off the mark
Yeah I like to rub it in too.

LOL, Elizabeth!! not only do you a massive lack of understanding of electronics (as exemplified by your many befuddled posts that litter Audiogon forums attempting to explain a technical subject) but you also have a massive lack of reading comprehension!
re-read my post & re-read Almarg's post.

03-15-12: Wolf_garcia
...you know...now that I think about it, maybe my sister is bipolar.

LOL! so, you get ear-grating, harsh distortion from her??? ;-)