No news from Outlaw on the ticket. I'm definitely interested in your results - remember when you asked what comb-filtering would sound like? Well, just download the files...and you'll know first hand.

It's funny - I think I may have actually purchased my unit in the first lot - I think I filled out a form to be on the proverbial waiting list when the 990 was announced...and I remember, upon receipt, noticing the comb-filtering (on FM) simply because it was my only analog source at the time. The thing is...I did log a ticket then, so I think Scott et al could check the records and verify that the unit had an issue from day 1 (or appears to have an issue from day 1 based on comments I have received from another 990 user - he's put his through the paces, listened to the recordings that I made (having downloaded them from the FTP site), and says his 990 does not exhibit the problem with analog sources). Good news for him...bad news for me.

It also sounds like Outlaw is rather busy with the release of the new processor - at least this is what I have been told (that and 'due to the age of the unit' it would be some time before I heard back from them). I just hope that a) my unit has a hard fault and outlaw will exchange it (again, a B-stock unit would be fine), or b) this is indeed a firmware issue that (perhaps) only affects certain revision level boards / architecture. I would be more than OK with a firmware update...but if it turns out that I am just stuck with it (due to it being an 'old' unit), then I will be very, very disappointed.

I can't look-up the ticket (when I first logged the issue with what I thought was the tuner, but in fact has more to do with the analog signals than it does the tuner per se), because I submitted it as 'old_school' (at least, I think that's the user name I used) and since then I lost my password (which is why I now post as "old_school_2"), but indeed, I remember hearing the issue then.

Frankly, I think I may have more analysis tools at my disposal than do the folks at Outlaw (that's not a slam, it's just a statement of fact), so I'm not sure what they could find - apart from what appears to be the issue, namely, a hardware issue.

There is one other test that I need to run - not so much to see if the comb-filtering goes away, but to see if changing the delay settings changes the comb-filtering characteristics (something that another owner discussed with me earlier today). I will try to run those tests in the next few days and see if that is part of the issue with my 990.

[ADDED: I tried changing the DELAY settings (i.e. speaker distance) to see if this might play a role / affect the timbre of the comb-filtering. It does not; Bypass and Stereo had the same sound (i.e. same timbre) and the Upsample mode had a lower pitch to it just as before.]

[ADDED 04/12/12: I have just uploaded the simulations that I did to find out if what I was hearing from the 990 was akin to comb-filtering; I have spoken of this in the thread (and the other thread), but I decided to post the simulations so that they could be compared against the actual data. Again, these files are synthesized. That is, these are NOT from the 990, but instead are files that I created to see if a simple delay-and-add was representative to the issue that I am hearing in my 990. TO generate these files, I performed a delay-and-add process using 1 ms, 3 ms, 5 ms, 8 ms (which corresponds to the delay observed in the STEREO and BYPASS modes), 9.3 ms (which corresponds to the delay observed in the UPSAMPLE mode), and lastly, 50 ms. The files appear in a folder called "synthesized_comb_filtering_examples". Each file is 30 seconds in length, two-channel, and is availavle in .wav, .flac, and .mp3 formats (a sub-folder exists for each format).

Note that if you compare the 8 ms and the 9.3 ms delay-and-add synthesized files to the actual data from the 990, you will hear that they bear a striking resemblance; compare the 8 ms synthesized file to the FRONT STEREO or the FRONT BYPASS files posted earlier and you will hear...likewise for comparing the 9.3 ms synthesized file to the FRONT UPSAMPLE file.

One note of caution - I did not normalize the magintude of the files, so some may play louder than others, but you can easily adjust the gain in your media player / app / device that you use to audition these; the thing of import is the timbre (character) of these synthesized versions as compared to the actual data obtained from the 990.