oppo's volume control

If the output impedance of the Oppo is low enough to drive the input of the poweramp (which it is, as all Oppos I know are less than 200ohms output impedance even less than 100ohms).
If the voltage output of the Oppo is high enough, to give more than loud enough volume in the system. (which it should have no problem in doing)
Then this constitutes a match, with the lowest order of colouration and distortions you can have of controlling the volume within a system.

If adding preamp into the system sounds better to the user, then it's the colourations/distortions of the preamp the user prefers sound of, this maybe making up for other tonal deficiencies somewhere else within his system.

Cheers George

To be more specific to my above comments, lots of Oppo 103 owners have reported pops and clicking when using the 103 as preamp. The 105, and 95 don't do this. The pop or click will occur when the Oppo is given a disc related command and stops, scans, pauses, etc. I experienced this myself and could find no solution.

Also, I found limitations in the SQ that my Oppo 95 does not have. Some have suggested that the clicks or pops occur because of DC bias that may be occurring in the IC's or coax cable connected to the Oppo. The shielding can build up DC bias, apparently. If I had the spare IC's(the kind that drain to one end only) I'd try draining away from the Oppo and then draining to the Oppo to see if that made a difference.

One of the Oppo gurus on the AVS forum thread has said the 103 is not intended to be used direct to preamp as the 105 is. Maybe someone interested can contact Oppo to see what the official word is.

The "official" word has been that none of the 10X series are recommended for use as a preamp although Oppo recognizes that many will want to do it.

FWIW, I have yet to hear any clicks or pops from any of the Oppos but I never use them without a preamp.

Just to clarify I was quoting Bob Pariseau who appears to be something of an expert on the capabilities of the Oppo 105 and he basically said it always sounded better with a preamp.

For me personally as well I worry about the default setting that can revert the Oppo back to full volume and if you are just using a power amp....ouch.

I really like my Oppo 105 by the way.

05-11-14: Kr4
The "official" word has been that none of the 10X series are recommended for use as a preamp although Oppo recognizes that many will want to do it.

I find this odd, but maybe it's for other reasons than sound, I will find out.
Kr4 can you post a link where it "officially" says this, Thank's.

He said, she said, they said, all MAY have ulterior motives for saying this.
But Ohm's and Kirchoff's Laws do not lie, and the fact is, the Oppo's are even better able to drive the inputs of poweramps than many active (especially tube) preamps can.

Cheers George