Bob,
Congrats! I enjoyed the videos you sent me last night.
SIDE NOTE: I kept telling Bob to get the PrimaLuna and he kept saying "I'm not buying anything unless its from you!" I really appreciate that Bob!
As jadedavid has indicated, you will have many years of enjoyment before you need to worry about replacing tubes. Some people keep a log of hours of listening so then know when they are getting close to 2000 hours, 5000 hours, 10,000 hours, etc. I know Steve here has over 10,000 hours on his KT88's (same tubes as in your amp) and they are still going strong. Steve is using upgraded tubes found here:
http://www.thetubestore.com/Tubes/KT88-Tube-Types/Genalex-Gold-Lion-KT88
I think I still have a bunch of these new in a box I can send you to try, should you feel the urge to tube roll. Tube rolling is a fun part of owning tube amps. By trying different tubes, you get different sounds. There are NOS (New Old Stock) tubes, which can be from the 50's, 60's and 70's (or earlier) and new production tubes (like the ones above). As far as KT88's are concerned, there are plenty of good new new stock tubes and NOS tubes are scarce.
For new production tubes, the word on the street is that these are very good:
http://www.goodcomponent.com/produc...z-replace-6550kt88factory-testmatch-1246.html
....but I have yet to try them myself.
The smaller tubes in your integrated amp are 2 x 12AX7's, 2 x 12AU7 and 2 x 12BH7. All will play a different role from input, preamp and phono. NOS tubes in these are the way to go and Andy Bowman of Vintage Tube Services is the guy to call. His website is:
http://vintagetubeservices.com/ (thanks to Jack for the recommendation of Andy) Andy can find the good NOS tubes for you as far as the 12AX7, 12AU7, 12BH7's are concerned. Remember, you need matched PAIRS of each.
As far as a tube starting to go, jadedavid has outlined it above. The amp will lose power, you will hear a lot of white noise, crackle, static, pop, the glow of the tube will be less or none at all. But like we've said, you have MANY years of enjoyment before you need to worry about that.
The tubes you have are stock tubes and they need about 100-200 hours to break in. They will smooth out after. For now, use the tone control to drop the treble a notch.
As for racks, I use the Quadrasphire racks like these:
http://quadraspire.com/ I'm not a fan of metal/steel shelves. Wood is best as it allows the energy from the electronics to dissipate without any ringing. You may want to call Chris at Timbernation (
http://www.timbernation.com/Highendaudiorack_PopUp.cfm) His phone number is on the website. He can custom build you anything rack you want. Just remember, if you're putting the integrated on the bottom shelf (leave the top shelf for your turntable), than make sure you leave AT LEAST 4 inches of clearance above the top of the amp for the heat from the tubes to escape. Based on your amp specs, I would say 12-14 inches high is what you want. 19 x 19 is a good width/depth.
As for the stands for your speakers, I would talk to a B&W dealer, maybe even BestBuy because they sell them, to see if they can order you the matching stands for your speakers.
Hope this helps and congratulations on a fine amp!
TUBES RULE!!!!