I'm having the same problem with my 970/7075 combo although I have to be pretty close to my speakers to hear the hiss.

1. It sounds a lot like the hiss from the old cassette tapes and only occurs on the tweeters.
2. It occurs no matter what input is active even on input with nothing attached.
3. It is somewhat linear with respect to the volume knob position (As I go from min to max on the volume knob it starts out constant than at about half way up it starts to get louder until it's pretty obnoxious).

I'm guessing the noise is being generated internally to the 970.

It's either a poor job of decoupling the DC power supply which I can't do anything about.
OR
It's noise being injected through the back panel ports. I'm thinking about trying some RCA Shorting Caps on the unsed inputs. Other forums point to unused RCA-type digital audio inputs as prime noise generators as they are high bandwidth inputs.

I've ordered a handful of these to try out:

RCA Port Cover/Shorting Cap

I'll post again after I try them out.

EEman,
That exactly describes what I'm experiencing. Let me know how those work out. Since they are a cheap fix I'll be ordering some too if that solves the problem.

John

Do you have dimmers on the lights in this room or nearby? I had hiss from this with an amp that seemed to be prone to this sort of interference.

Nope, don't have any dimmer switches in my house at all.

Do you have an antenna hooked up for the tuner and is it grounded? Try removing the antenna and listen for the hiss. The 970 does not have a grounded plug so maybe your have a ground loop somewhere in the system. If any of your gear has a 3 prong plug, pull the plug and try the system. Have you switched the bass management switch? Does it change the sound if you do? Also, make sure all of the rear panel connection points are clean and clear of any debris which could be shorting them out. With EVERYTHING disconnected from the 970, except the outputs to the 7500, is the noise there? Does the volume increase when you turn up the power? If so, call Outlaw. They have a lot of experience with ground loops and all sorts of other stuff. They will help you out.

The shorting caps were not the solution.
I also tried XenonMan's suggestions and none of them changed the characteristics of the noise.
Back to the drawing board...

Sounds like the 970 needs some time at home with the Outlaws. Is it still under warranty?

I unplugged my 970 from the Belkin surge protector/power strip and plugged it directly into the wall. No change. Guess I will have to call Outlaw next week (mine is still under warranty). Just hate to have to send it back (if that's the remedy).

Talked to Scott...my 970 is going to take a trip back to the Outlaws.