Recommendations please for good, affordable pre-amp for system?

Congratulations on the Bryston and Thiels. My Buddy has that amp and the matching preamp. I have Audire and they are certainly comparable.

eBay currently has an Audire Legato or $175.  I don't know of any other brand that compares with this preamp or less than $500, unless you get really lucky and/or find an Audire Diffet 2 or 3. I would imagine a B&K would be good (I have their truly excellent sounding tuner.), but I have never heard any thing else from them.

Bryston is very good, but due to national marketing, compared to Audire's limited market. the name costs a lot more.

I will tell you some preamps we have tried that sounded really bad with our Audire and Bryston amps: GAS Thoebe, Rotel, SAE, and Phase Linear/Carver (Not too bad, just not worth the money).

Although I never had a preamp from them, I immediately sold a Sumo amp I tried out. GAS and Sumo had the same designer. His Thoebe preamp was rotten to the core with the Audire or Bryston.

Brands like GAS, Hafler, and Phase Linear were designed well, but manufactured by the lowest bidder, whereas Bryson and Audire were made in house with the designers' overseeing production.

A small step up (from my somewhat limited experience) would be Theta, Threshold, Bedini or Mark Levinson, but they are overkill for your Bryston. I love Audio Research, but it is out of my price range. 

NAD and Adcom  have good names, and I liked my NAD amp OK, but sold it for a second Audire. The NAD was clean and relatively powerful, but did not separate the instruments from each other, while the GAS, Rotel, and Adcom preamps I tried were not good sounding at all.

Since John Curl designed some Adcom stuff as well as Mark Levinson which I have owed, I would imagine the Adcom pieces he did are good, but my experience with their preamp was not good, soundwise.

Regarding your quest for cables, I generally buy used ones found on Ebay or here on AG.  Sometimes new when sold at discount.

I use Audioquest for interconnects, starting with lessor expensive ones and worked my way toward better.

Music Direct is selling AQ diamondbacks starting at $55 for a 0.5 M pair. You might try these between pre and amp and CD player and pre. 

I have purchased on Ebay some Esoteric USA interconnects that seemed to be will designed/made and truly inexpensive.

Check out Blue Jeans Cables for speaker cables. 

There is a Parasound P-3 Pre for sale here on AG. Asking price is $450. Might be one you could use until you upgrade and sell without much loss.

Thanks all, for all your thoughtful and detailed comments. It's incredibly helpful, and I've started a new bookmark folder just for these suggestions. A world of information here! Thanks a ton!

A used Placette Remote volume control would offer the highest performance possible in a passive in this price range. The Bryston has 1.3v input sensistivity setting which would help overcome any passive limitations. The use of a passive also depends on your sources. If the source has enough oomph the Placette will give incredible dynamic and bass performance along without blurring the sound with an additional gain stage (engineering seems to fall down in the area of passives, but oomph might be voltage output and lower output impedance). If your sources have oomph, I'd put a Placette on the used shopping list and check it out. This model only has one input and one output, but other flavors of Placette are possible that add features including balanced connection.