Studio Signal Flow advice 01

I am in the midst of building a new editing studio and am new to high end audio. I currently have a pair of B&W 804s driven by a Bryston 4B NRB. Which so far, to my naive ears, I'm pretty blown away by. My question is am I destroying the benefits of decent equipment by my signal flow. All the audio sources for the room feed into a Mackie Mixer with the mains feeding a pair of Genelec near field powered speakers and the sub going to the Bryston and 804's. Am I destroying the signal by going through a cheap mixer sub output? I am considering going from the mixer sub out to a tube pre amp before going to the Bryston. Will the signal be cleaned up with this signal flow. I don't know how to avoid the mixer. Thanks for any input.
I'm using a custom 48 channel John Oram BEQ-PRO(over $30K, can send pics) and wouldn't think of feeding my audio through it. Regardless of how good your mixer might be, the more connections, cables, pieces of equipment(and their passive/active devices) you send the signal through, the more original information you lose. Avoid the mixer by buying a high-end preamp, and you'll have a discrete playback system. Engineer on one, listen on the other, and in different rooms(if possible). That's unless you have to use the 804's as monitors. I mix with headphones, or Tannoy near-field monitors.
Thanks for the advice. Since the Makie mixer wouldn't hold a candle to your John Oram, I think a pre-amp is the way to go. I can have the sub outs feed one input of a decent pre-amp and have a good quality CDP or ACD feed another input for a better listening setup.

Does anyone have a suggestion on a pre-amp model that I could buy used for under 1K that would pair nicely with the Bryston 4B NRB / B&W 804 mix? I'm kinda partial to a tube sound that might SLIGHTLY warm a pretty bright amp and speakers. Rack mountable is also a big benefit for me.
Any comments on the Audio Research LS7?
Just about anything made by ARC is a good way to go. I've owned an SP9, and an SP14 and loved them both. Wonderfully transparent after I upgraded the power cord(installed IEC connectors to both), and plugged in some NOS Siemens E188CC tubes(I'd use CCa's, if I had to do it over). The SP14 has a "bypass" switch that eliminates the balance and mode controls from the signal path for even more transparency.
I forgot to mention(but- you probably already know): ARC will sell you a rack mount faceplate for anything they build(pretty cheap too).