Question for Parasound Hint 6 owners

I was told it was not only "ok" but beneficial to leave solid state equipment on all the time. I had been shutting off my Hint 6 because i wasn't using it that much. Been using it more lately so i decided to leave it on and IT GETS VERY HOT even when not used. Came home after work and put my hand on it...hot.

1) is it normal for this unit to get hot even when not in use?
2) should i just shut it off?

3) Unrelated. Which input gives best sound? generic laptop using USB playing 320 mb files? Ipad using Aux on front? I do not yet own a streamer and only own ipad, laptop, and CD player connected with digital coax.

I just want to get  the most out of this amazing amp.

Thanks.