Then the problem must be before the amp, not the amp itself. To check the cable leave the amp ends of the XLR cables where they are and swap the 990 ends LF <--> RF. If the noise stays put the problem is the cable, if the noise moves the problem is before the cable (990, source).

No What I mean is that no matter which channel of the preamp I connect to that particular channel of the amp, that's where the noise is. So for example, if I connect the FL that speaker has noise, if I connect the Center - that channel has noise...etc. The other channel in the amp is fine, so I am running my center on that one, and I'm using another amp I had for mains, and it's quiet.

Are you using the same balanced cables to XLR inputs on the "another amp"? (Just checking to make sure it can't be a defective cable). If so, and the noise happens on only one channel of the original amp, but only with the XLR input and not with the RCA input, then it must be a problem with that channel of the amp - either the XLR connector/jack or the op amp that takes the difference between the two signals in the balanced input. All the circuitry after that point is common between the RCA and XLR inputs.

Yep, using the same cables. I did try swapping cables around at first, just to see if maybe it was one of them, but they all shared the same results. It's not a huge deal, I have a work around for now and a new amp on the way. Once I get the new amp, maybe I'll take this one apart and see if I might be able to fix it.

Just thought I'd post an update:

I've decided to keep the 990 over the Pioneer Elite 54TX. The detail in surround sound for both movies and music was simply too good for me to settle for less. There are some quirky things that I can live with (more like work through), but overall, it's really grown on me. I really like the multiple crossovers, the upgradeability,the surround presentation, the plethora of inputs, and the initial ease of use. Bass management takes a little getting used to, and I'm still working on it, but I have dialed it in much better than it was originally. One thing in particular that I really like is that I often find myself listening at reference levels, especially with movies. I was not really able to do that with the Pioneer; it didn't have the clarity and definition that the 990 has. It's a great piece at a great price...how could I pass on it.

Anyway - Thanks to all who helped and chimed in on various things.

Glad to hear that it's worked out for you, Bri.

I have a question (or series of questions)Is therea reason for the lack of a three prong plug. Wouldn't it only make sense since most amps are three prong? Is it a truly balanced system without a third prong? And lastly, are the grounds of the balanced connections tied to the signal ground or the chasis ground?

Thanks,
Brian

This thread may interest you - it touches some on why a two-prong power cord was used.

Thanks Gonk.

I have another question:

In 2.1 channel analog, my sub is playing well above the corssover...meaining Full range...I went through all of the settings and I can't find anything out of the ordinary...what am I missing?

Thanks,
Brian

Are you in analog bypass mode? If so, the digital bass management is also bypassed (since the signal never enters the digital domain), and the 990's approach to dealing with that when the mains are set to small (and therefore are requesting help from the sub) is to make a copy of the left and right channels, sum it, and send that summed full-range signal to the subwoofer.