Oppo BDP-83 optical out for 2ch stereo from blu-r?

The response would depend on the quality of your DAC and digital cable. The only way to really know would be to try out both options.

My toslink cable is a Wireworld Supernova 6 glass toslink, it goes into the toslink input of a Wadia 860x cdp (which in this case is serving as a digital "pass through") and then out via Kimber Select 2120 xlr digital coax to a Weiss Dac2 (the Weiss doesn't have a toslink input).
FWIW, Oppo has just replied to my inquiry, they say to use the analog stereo outputs rather than toslink. They say that way I can use the Dolby Digital TrueHD or DTS-HD formats.
But, you're right, I'll just have to try it both ways. I had assumed that by utilizing my outboard dac I would get superior sound. I'll have to try the settings for the analog outputs and see what happens.

It makes no sense that this is a question at all via you are not running surround format.. 2 Channel the easy answer is regardless of format, 16 bit 2 channel stereo vs. 24/196 for a movie going thru 2 channel systems matters not.

Take a connection to your DAC which should be far superior using the oppo as a transport running 2 channel which bypasses all the decoding B.S. in the unit, and run a 2 channel analog line separate into another input on your preamp and then you can compare which you like better by hitting a button to switch on the fly between them both. I would test this running standard 2 channel CD, and DVD movies, Movies I can guarantee will make virutally no difference, however CD for music should be superior thru your DAC setup via optical considering you have some top grade gear with wadia and Weiss.

This is the easiest and best A-B test you can do, then you get to hear the oppo as it translates the format and without even getting up from your chair or changing the music get a nearly instant comparison on drums, vocals etc...

Thru both D-A convesion methods.By the way Blu-Ray concert DVD's are far superior from my testing running thru a good DAC in 2 channel. Otherwise you need some seriously good multi channel systems to beat a superior 2 channel setup, not that it can't be done, but you gotta fill a room with a lot more speakers, wires and gear to come close. And room acoustics become even a bigger mess to get right. Don't get all caught up in the hype of high numbered D-A conversions etc..

It all comes down to how well that Blu ray or CD or SACD was mixed and produced on the recoding itself and how it ends up sounding on what your equipment is superior at re-producing not what the specs. say trust me on this.
Good Luck

I haven't done the A/B listening yet, my Oppo and my stereo rig are 3 meters apart. I have the 3 meter glass toslink, not the 3 meter analog ic's. I thought I'd get some opinions before I sprang for a pair. BTW, I won't be using the Oppo as a cdp, I have the Wadia 860x for that. The Oppo will be used for blu-ray & dvd, many of which are concert recordings. Thanks for your input!

Thats fine, I understand you have some hi end gear and cables, which means you can easily hook up the toslink and not the analog, I just highly suggest you still try it this way even with 6 dollar 3 meter walmart/radio shack analog cables to get an idea if you are really looking for blu ray being better thru the DAC or oppo.. I would just run the optical to your dac, bet is it will be just as good or better.