Might ask VA Canuck - based on this thread he has paired a BDP-83SE with a Boston Acoustics AVP7 (which is built on the same Sherwood platform as the Model 990). He's the only person I have found who has this exact pairing, but I don't think he had the stock BDP-83 previously.

I can't tell you if the upgrade is worth it or not but I'll tell you my experience. I had a PS3 connected to my 990 via optical. Like most everyone else, I wanted to hear the new audio formats. I decided to get an OPPO. Since this was a new purchase (not an upgrade like you) I went ahead and got the SE model. Since I was going to have my equipment rack torn apart anyway, I got a Panamax power conditioner too. Long story short, I have the OPPO connected to the 990 via 7.1, stereo, and optical. I used the Outlaw PCA cables for the analogs and a Blue Jeans cable for the optical. I can easily switch back and forth (via the remote) while listening. I have very resolving kevlar cone speakers. I may lose some credibility here, but, the difference between any of the connections is very subtle. I changed the power cables around too during this process but from memory, the difference between the OPPO and the PS3 is very subtle too. To be honest, I was actually a little disappointed there wasn't a bigger (night and day) difference. If you have the money, do the upgrade - you'll never wonder if you should of. If you don't want to spend the money, I personally think the difference is so subtle you're not missing much.

og33, that was me with the issue. You said it, "fixed itself?" Mine seems to as well; after the last FIRMWARE update on the Oppo. I have been WAY too busy to test everything out, but the bass is much punchier and I only have it at +6.5 with the other channels at 0. I think something got fixed, or maybe reset on my unit, with the update.

I actually have the RMA now to get my Oppo upgraded to the SE. Let's hope that doesn't "break" things again! While it is getting serviced, I will have them check out the sub with LFE.

BTW, the opening of Half-Blood Prince (Harry Potter) is excellent for checking LFE.. just listen to the thunder.

My guess is you are running into the ADA conversion mentioned above, since the 990 does not have an analog pass-through.

I listen to a lot of vinyl; trust me, no matter how good the DAC is, it will not sound better than direct analog. Keep It Simple is aways better for a signal path.