Audio Research or Conrad Johnson Tube Pre-Amp???


I am looking at the purchase of an Audio Research SP-9 or SP-14 or Conrad Johnson PV-9a, PV-10, PV-11 or PV-12 pre-amplifier. It's very difficult since I've not been able to hear every one of these pre-amps. However, I do want a tube pre-amp to mate with my Threshold S/300 and Mirage
OM-9 speakers. Later I plan to purchase Magnapan 1.6 speakers. I will also be using an Elite Rock Turntable with Excalibur tone arm. I will also be using two professional tape decks for recording and playback.

I really need assistance regarding the following:

1. Which pre-amp will work well.
2. I also need to know which tubes are the best for a particular pre-amp?
3. how long do tubes last normally with 2 hours daily use?

Any other information you can offer would be greatly appreciated. Thanks so much all.
4. Does turning on and off the tube pre-amp hurt it?
rbwinterlink
IMHO, you shouldn't try and pick audio components on other folks recommendations. Are we going to listen for you too? You need to use your own ears, and there is simply no substitute for that. If you chose something that is recommended to you on this forum, you will be choosing what someone else likes, with his/her other components, in his/her room. As you can see already, there is no universal concensus here. So make your own - go visit some local audio dealers and LISTEN! Doing it any other way is just a crap shoot.
IMHO makes a good point. However, there are many of us who do not have the opportunity to listen various audio components. I fall into that catagory. So to all who have rendered honest opinions, THAN YOU MUCH! Believe me I do appreciate.
I have been a big fan of CJ's Premier 10. Owned three, still use one in the HT set up. Affordable, huge soundstage, not too warm. Also check out the Motifs... best of both worlds.

Peter
if you can't listen, you take a big risk. you might as well flip a coin.

i have owned sveral cj preamps, but not the one's you are considering. i have heard the pv 10, as i auditioned it in my own system. i wouldn't own it.

if you can't listen, get a good deal and be prepared to resell the preamp.

i won't recommend one or the other, because only you can determine what you like.
I want to thank each of you for responding to my request for information. Your kind suggestions are appreciated.

Bob