CD Direct to Mono Blocks or Preamp???

Audio Research isn't the best match to 7B-St since it has very high gain that you don't need. One of the best active volume controls that would give you a full sound + maximum transparency IMHO is either McCormack RLD or Wyred4Sound preamps.

Oh, Forgot to mention to suggest to go balanced from source to amp.

I like your idea of adding the Bryston preamp as it has always been my goal to match brands here whenever possible. I would highly suspect you will retain all the detail, improve tonality, add a touch of warmth, and have better imaging while keeping your current CDP.

I would think the only reason to interject a preamp between your source and the Brystons is to better match impedance mismatches. If the source can readily drive the input impedance of the Brystons to full power, then I am not sure I see the advantages. The input impedance of the power amp will be about the same as the input impedance of any pre-amp, so from the source point of view, its the same load. Perhaps with a pre-amp, the source will need to produce a lower voltage range (because of the added gain of the pre-amp), and this could give some sonic advantages.

For example, the power amp might require a voltage of 1-2 V for full power, whereas the same 1-2V could be derrived from the pre-amp with the source providing only a few hundred millivolts. If the source uses IC OPamps, then the lower the outpout voltage the better. If the source has a class A discrete output stage, this would be less of a factor.

I used to use a CA 840C to drive my power amps directly, but I used a passive attenuator for gain control. So this placed a resistor attenuator between the power amp and source, which is a compromise (impedance/load) at best. I discovered the attenuator (5K) was way to low for the OPamp output of the CA 840 to dive properly. Sound was clean and detailed, but significantly devoid of bass response.

Thanks for all your input...I'm new to this and really appreciate you sharing your experience. I think I'm going with the MCD 1100 (over the Bryston BP-26 running my Cal Audio CL-15 for now) unless there's someone who has actually tried the Bryston Pre-amp vs. MCD 1100 (or even the MCD 500) and thinks there's a reason to go pre-amp. Again..thanks to all.