Best way to connect 2 preamps to 1 power amp


Hi,
I have 2 preamps; 1 tube 2-channel for musics; 1 solid state pro-logic 5 channel for movies; both have RCA output. The power amp for front channel is lexicon 212 (Bryston 3bst); has both xlr & rca inputs w/ selector switch. Shall I:

1) use rca y-adapter for the 2 pre-amps to the 212
2) Use rca for the tube & xlr (w/ rca xlr adapter) to the 5-channel. Use the selector switch to change source.

Please advice any concerns/problems for any/both connections. Or any other better solutions.
Best
davidcpl
Why not Email Bryston Canada and ask them about using the switch on the back for bal/rca. I'm sure they have had this come up before, I've wondered about this myself but have always used 2 systems.
Wow; you guys are awesome. I will try the suggestion from connecting the HT to one of the line-in of the tube. (I don't know I can do that). Also, I have some concern of switching over back & forth on the RCA/XLR as it will eventually become loose.
Thank you once again guys.
I also found out there is a by pass on the HT (Audio Refinement Pre-2DSP) whereas the tube doesn't (YS-Audio Symphonies Plus R). But I love the warmth on the tube. Is it of any use; please advice.
No use in this case because you want to send the processor through the tube pre instead of the other way around.
Thanks to all. I did ask Bryston regarding the input switch........... They said...... "The input switches are not made for that kind of repeated use and could damage your speakers if used in this manner."
CIAO