Buy new tubes, or use "stock tubes?"

If YOU do not know about doing this, I would say you should stick with the stock tubes. Tube rolling is complicated. I NEVER wanted to really get into it. I found an Audio Research SP-10 and sold it primarily because of the 'tube' problem. I bought an AR SP-15 (it has only 3 phono section tubes, instead of the 15 tubes in the SP-10)
So, IMO stick with the stock tubes until you have a LOT more information.

I completely disagree with Elizabeth!

You should immediately go out and buy as many expensive NOS tubes as you can find. (And, at least one of each type, and better yet, two, as you'll instantly have a backup set for the ones that you like the best!) This will allow you endless fun listening to the same music, over and over and over again, comparing the different tubes! Nothing says "Confirmed Audiophile" like a guy with hundreds of spare tubes! Oh, and don't forget to buy a tube tester while you're at it! No TRUE Audiophile is without one!

Elizabeth, on the other hand, didn't want to buy any of the multitude of tubes I had for sale, (let alone the tube tester!), and instead, (foolishly I might add!), chose to spend her time listening, (and somehow, enjoying), her music, foregoing the pleasure of endlessly swapping out tubes, and exactly how each and every tube differs ever so slightly in its sonic attributes! (Silly girl!)

;-)

I have a Mcintosh MA2275, tube rolling made a huge wonderful improvement........ the stock tubes were horrible. I've bought from Upscale Audio and The Tube Depot with great results.