This post may be dead, but i'm still going to share.

I also had the problem of crackling and distortion, which would only happen occasionally, but I was able to resolve it with help from Outlaw Customer Support.

It turns out that the DSP chip in the 990 is very sensitive to heat buildup. I had the 990 right on the top of a 12 channel amplifier, which would almost start glowing red after being on inside an MDF enclosed rack all day. Suffice to say, I believe that the sensitive chip cannot handle any heat above what the 990 itself produces.

I'm not so sure that this is a serious defect in design as it is just the nature of high-end electronics. (I know that when my computer's fan quit working awhile back, the performance definitely suffered.)

I would love to hear if other people have found evidence to suggest that this is in fact a fix. All I know is that when the 990 temp. is normal, the distortion is gone!

Heat is dangerous in any equipment like this. My 990 operates fine in my closed cabinet, but I have the big power amp fairly well isolated and I have a remote temperature sensor (the outdoor portion of a cheap indoor/outdoor thermometer) that has over the years migrated throughout my equipment rack to help me keep an eye out for dangerous hot spots.

Interesting story: we had a client some years ago who kept complaining of major heat problems with his equipment racks. This was in the main equipment room for a TV/radio studio. He reported that the ambient temperature in the room was in the mid 80's, even though we designed the space to maintain 72F. It turns out all thirteen equipment racks were fully closed up (unventilated rear panels and glass front panels) and the temperature reading was from a stick-on thermal strip attached to the back of one rack. Temperature readings on a nearby wall came back at 68F, four degrees better than the design temperature, but any time the air handler serving that area shut off he would burn up gear. The solution was of course to leave that air handler on around the clock, as was already being done in two other areas (server room and archive room), but I don't know if he ever ventilated his equipment racks...

Yeah, I've had the crackling distortion too, but I don't think mine's related to temperature. The 990's on its own shelf, with plenty of breathing room, and my rack is wide open. My amp is below the 990, but it does not run hot at all. The distortion comes and goes, and it's been most prevalent on "Upsample" mode. It's gone at the moment...

Hope nobody minds but I'd like to keep this thread alive. My 990 did this distortion thing almost out of the box. And this week it's happened at least 3 times. A power cycle or two has thus far always cured it. My advice is don't anyone panic and just live with it. It's a minor inconvenience for something that to me, really delivers the goods.

have you contacted Outlaw Audio about the problem? I'd be concerned that it may be damaging something.. since most of the rest of us don't have this kind of distortion.. it would bug me till i got it resolved.

are you sure it's not the 7125 amp and not the 990?

I contacted Outlaw about it, and the answer is always to reinstall firmware. This takes care of the problem for a while. Then it comes back, and then it goes away. It's usually only on "Upsample" mode, so I can work around it easily enough by switching to a different "mode" (and therefore it's not the amp).

Sky, yes I have contacted them. And they have given me the procedure which I was already doing: power cycle. Their impeccable customer service did suggest that if I wanted, since my 990 is under warranty, to send it in. But as I've said, I'm not that worried.

well, it sounds like there is an ongoing problem.. since it requires service.. that's why companies have warranty's, for problem that crop up in the first 1yr, 2yrs or whatever.

If you can live with it.. more power to you. I would be upset to have to live with a problem like that.

good luck.

I still have the problem too. Sometimes a month or more goes by without any problems; other times it will happen twice in a week. The problem is that the 990 produces unlistenable distortion for any input in any digital mode. In 2 channel bypass it sounds fine.

Turning off the main power button on the back for 10 or more seconds cures it almost every time but once in a while I have to wait quite a while and then the problem disappears.

I wish the Outlaws were able to tell us what the problem is and provide a permanant fix. But even with the problem, I still love my 990!

To me it almost sounds like a hardware problem, the very fact that cycling the power takes care of it makes me think that a contact is not being fully made. Kinda like a switch that doesn't quite hit but makes enough contact to pass the juice resulting in a dim glow. But give it another flick and wallah let there be light!

I have no electrical knowledge other than working in the automotive industry where occasionally I do have to troubleshoot switches and lights. But I have learned to check for the obvious first because that is usually the problem, it's almost never some weird voodoo from a parallel universe.