PREAMPLIFIER UPGRADE QUESTION

I am a beleaver in a tube preamp and ss amps. None of your choices would be on my list because I like everything to match (I am weird like that). Good luck with your decision!

Most posts here recomend the device they own and listen at home. That's a good thing because they love what they heare. Ultimately, that is also your goal.
My recomendation for you: Ask your Conrad Johnson dealer for a demo or better if he could lend you a ET6SE for a month or so. I bet you will refuse to return the device. All combination tube preamp combined with a solid state amp I've heard did sounded exeptionell. Allways better than cominations like tube/tube or solid state/solid sate.

Don't leave out the Wyred4Sound STP-SE. It has the unique properties of both passive and non-passive architecture. Very neutral without sounding dead.

Thank you all for your kind and instructive responses. My choice is between preamplifiers as follows: Conrad Johnson:ET6 SE, Rogue Audio RP-9 and Bryston BP-19. Just purchased the Bryston 4B3 cubed power amplifier. The reason that I am limiting my future purchase to the three listed is because my dealer is a representative of the three above listed. He represents others as well, but they are not within my budget. In any case the dealer's knowledge and service is excellent and would like to continue working with him. The problem with the Conrad Johnson is that it does not have a balance control which I require. My current Rogue Audio RP-1 has one and I find it essential. 

Assuming that you are referring to LEFT and RIGHT balance levels. I had the same issue with my Holo Serene preamp. I wanted it in my office where I sit off centre and really need balance to make it perfect. My Benchmark LA4 (now HPA4) preamp had the analog balance control and thus worked better than the Serene in the office. However, for esthetic reasons I wanted the Serene in the office and the HPA4 in the Livingroom (no balance control needed there).

I solved this issue with the Serene in my office using the following approach:

Audiogon Discussion Forum

The result of this was even better than the analog balance control of the HPA4. The Serene sounds perfect now with the settings described in my link. Nothing is compromised with the approach I used.

There are a lot of suggestions made on this thread for preamps that could not only save you money but also get you better sound. You can learn a lot about the sound of any preamp from reviews and posts in places like this. You need to first figure out what sound you are after.

Your Bryston 4B3 is supposed to be slightly warm sounding. For my tastes adding a warm-ish preamp is too mushy with the 4B3. I go with something more neutral. Maybe your Bryston BP-19 choice would be what I would choose. However, I had a Bryston BP-20 preamp years ago and it is nowhere in the class of the neutral LA4 / HPA4 or Serene preamps.