Is this normal? (amp)

on my denon stereo amp if for exmaple my only input plugged in is the cd player into the cd player input an its playing when i switch to any of the other inputs an turn volume up to about half way i can cleary hear whats playing on the cd player.

 

It's normal as in any other amp of the same model will do the same thing. It's a matter of how the input selection is done. My old rotel RA971mkII does the same thing, as does my parent's RA1062. My NAD S300 (RIP) doesn't. This is because the RA971 (like most sub £1k integrateds) uses a multi-pole switch for the selection, with wires/traces close to one another whereas the S300 uses individual relays right by the back panel, spaced about an inch apart.