I asking for suggestions in choosing a pre-amp [that won't "break the bank".

In that price range, new I’d recommend Mytek or Schiit. Both very good, and relatively immune to source quality. Meaning if you use your Oppo’s digital outs they’ll still sound good.

I like Berkeley Audio Design but they are pricey and sound a bit cool to me.

Ayre QB-9 is great, but quite source sensitive, even via USB. Some other listener has confirmed it's still the case. You don't know this until you do a back and forth test with a Schiit or Berkeley. Sounds great with their CD players though.

I would have more suggestions, but I haven’t been listening in too long a time.

The Oppo 105 has USB outputs, so any DAC that has USB 2.0 support AND is "driverless" for Linux/OSX will work by the way. :) That’s your best sounding option.

Eric, my thanks for your input.  

Does anyone one have any experience with Wyred 4 Sound's Dacs?  Specifically, DAC-1 LE or DAC-2 Series?

Find yourself a used Bel Canto Pre3 and you will smile. $900 to $950 and it is very good indeed. No need to spend more. 

I owned it in between some big $$ tube preamps and it is the real deal. 

Use to own the primaluna prologue three preamp, just ask Kevin at Upscale audio about the sound your after and he will point you to the correct tubes. Could not believe the difference it made when I dropped in some mullard nos tubes. Can find them used under $1500 dollars and will compete with preamps at triple the price. Best of Luck

The Rogue Audio RP 5 is a full function pre that will drive most any amp.  Tube gain and line stage with solid state phono stage.  Full funtion remote and it sounds killer.  Look up the Rogue page and find a local dealer.  You will be impressed.  Also consider the RP1.