Upgrading to Tube; Amp or Preamp


I am currently looking to upgrade my existing system a piece at a time. I currently have a set of Vandersteen 2ce Sigs, VPI mkIII w/RB250 Origin Mod w/Dynavector cartidge, Adcom 565 Preamp, Adcom 555 mkII w/Musical Concept mod, and a Rega Planet CD. I have a rather small listening room, 15x18 w/vaulted ceilings and want to migrate to tube gear. I have heard the Rogue 120 amps and 99 preamp on the Vandersteens and thought they sounded marvelous.

I am into analogue mostly classical, jazz, and some rock. My budget is in the $2000 dollar range and since I want to get as big a bang for the big would it be best to replace the Preamp or Amp. The Adcom gear is a little too bright and the soundstage and imaging are not near (imagine that)what I heard with the Rogue combo. I like the Vandersteens alot but have heard that they get a little too laid back with tube gear. My aim is to put about two to three thousand in my system a year until my wife stops me.

Look forward to the suggestions, oh yeah getting rid of my wife is not an option (ha, ha).
rav1952
I believe that the preamplifier is where the money should go first. There are some super used deals on Audiogon at the moment. No need to spend more than $1000. I saw products by Quicksilver, Anthem, Audio Electronic Supply,
VTL and Cary over the last few days that would all be excellent "no risk"choices.
I think 'wellfed' is a mite optimistic regarding Atma-Sphere used prices....$2500 would be a little more like it and maybe that would include the phono stage. I owned a 565 for a couple of years and a friend of mine still owns one. It's a very good preamp. Maybe the phono isn't the best, so perhape looking for a stand-alone phono would make a little more sense. There are a bunch out there on the used shelf for reasonable prices, but that's another story. BTW, I own a new Atma-Sphere MP-3 with phono stage, it's quite something.
I agree with Travis that I am being a little optimistic about the price of a used Atma-Sphere MP-3 linestage. My brother picked one up on eBay about 3 months ago for $1,950 so it is not outside the realm of possibility. They do not come along very often but are worth serious consideration if you can find one. I am sure Travis is REALLY enjoying his music as are my brother and myself.
I plan to enjoy it even more when my speakers arrive, hopefully very, very soon. Best to you, Wellfed.