Adding a preamp to HT setup


i Have been convinced that adding a good preamp with HT bypass to my system will improve my 2-channel listening experience. I have read multiple threads here, and reviews all over, and there is an overload of information.

the 2-channel system is Aerial 7T’s, Odyssey Stratos amp and Oppo UCD205 player (I still use discs), and I’ll feed streaming in to the Oppo from the Marantz pre-pro. No vinyl.

the room is 19x12x8, and ‘live’, hardwood floors with a rug, drywall all walls. The rear of the room is open to the kitchen.

the improvements I seek are in soundstage focus and solidity, along with depth. Greater resolution of detail (love the little things that come out of recordings that make it real), and air around performers. All the things that draw us into a performance and involve our emotions.

i have an interest in what tubes would bring to the party, but I have no interest in spending all my time swapping out tubes to tailor the sound, I just want to listen to and enjoy the music. 
HT bypass is a must, obviously, and I’m curious about the lifespan of tubes given that my ‘normal’ everyday use of the system includes tv/movies where the pre won’t really be involved, except to pass the signal. I don’t know if there is an option for a pre amp to pass the signal through when not turned on, but that would be my preference.

Music interests range from Dire Straights, Pink Floyd to The Tenors/Josh Groban, to instrumental guitar...vocals and instrumental realism are big for me.

im comfortable buying used to stretch dollars, and would like to keep it below $2K, but would double that if convinced it was worth it.
english210
My amp won’t work like that. It’s an Odyssey, and IIRC, the RCA and XLR connectors are wired together inside the amp, so it’s not a true ‘balanced’ amp, and doesn’t have the switch....at least that’s what my foggy memory is telling me from a couple years back when I was trying to determine if there would be a benefit to going ‘Balanced’. Open to correction if someone else knows better, which is likely :)
Luxman I also heard the new EVO400 at my local dealer and the system sounded great. It just didn’t have any of the equipment attached that I have, so who knows. They will let me trial it though...I’d rather narrow down my choices before taking them up on it. 
Any input on tube life if the preamp has to be in for HT bypass? I read in the EVO400 manual that it does.
I had my Prima Luna for 3-4 years and didn't have to change tubes. They build their products w/lower gain to preserve tube life. My current Luxman CL38U-SE is 2 years old and as quiet as the day I bought it. The only tube preamp I had a problem w/was a CJ ET-3 SE. Has about a 26 gain factor and just ate the 6922 tube very 6-8 months. Was like clock work and it got noisy. Like sitting on a time bomb. That was my personal experience.
By the way give Klaus a call see if it's ok to hook up both the balanced and RCA. You can also try it if you borrow the Prima Luna.
I’m interested in trying tubes, but not hellbent on it. I found a Hegel P20 used that would work too. On this thread, the recommendations seem to be heavily on the tube side. So the consensus is that tubes will sound better?