Hum in system when only amp is on

I do normally turn the pre on first. However when a dvd is inserted there is a hum until the bit stream is sent to the pre. (this system does dual purpose HT/2channel)

I did try removing the ground, and the hum went away. But I see that is not advised by Theta. I will use automation to mute the pre to solve the hum problem.

Also I will switch the direction of the IC's.

Thanks for all your help. You all are very helpful. I thought I knew how to set up this system, but now I see there is so much more to know when dealing with seperates.
As always enjoy the music...

Ian

Ian, in my heart of hearts, I feel the warning from Theta is mainly a liability issue, and that you shouldn't be paranoid about ruining the amp if you float the ground . . . . . but if you are, then ground the amp, but not anything else (oh, and then point the arrows of the preamp-to-amp ICs toward the amp as I mentioned earlier.)

Neil

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Try removing the grounds on the other components and see if the Theta still hums. I know the Theta does have a little different grounding scheme than some amps.