Best Tube Integrated

I'm looking to experiment with a tube or tube hybrid integrated amp. I don't really want to exceed the $2000 used range. I currently own a Krell KSA 250 and I'm running Dynaudio Contour 3.3's. As you may be able to tell, I like big output with a lot of bass. I realize that tubes probably won't give such bass and output but I just want to find an integrated that's known for having some juice. The main thing is I just want it to be warm and sweet. Any suggestions?
I would keep my eye out for a Jadis Orchestra Reference, JOR, on Audigon which should come in under your "less than" $2K price point. I puts out about 50 WPC and particularly with KT 90 tubes has a lot of punch but still a lot of tube sweetness.
Aronov LS-960I, now available only used.
Provides your requested "big output with a lot of bass," as well as "having some juice."
Specifically renowned for enabling forceful, faithful-to-the-music bass, limited only by a speaker's abilities.
Sounds very natural, easy to listen to, realistic, with music free of any dryness, or listener fatigue, rather than specifically warming up, or sweetening.
Does allow recordings to sound their best, and definitely avoids what is less captivating about many solid state designs.
One of the very few modestly priced tube designs that delivers the kind of profoundly satisfying bass that can thrill the audiophile heart.
From the way you described your listening preference, any choice that fails to deliver great bass might be a short-lived experiment.
DK Designs VS.1 Reference Mk.III integrated amplifier.
Heard this peace on a few occasions. I was really floored when I find out it was around $3000 new. However take my recommendation lightly because I never had this peace in my system for evaluation. But if I was looking for a integrated amp it would be this or Manley's Stingray.
In your system, DK would probably be a better choice.
Try a Cary SLI-80 Signature, it should fit the bill.

I agree with Bbro that the Jadis Orchestra Reference is a very good option if you are looking for good bass performance. It also proides you with the option of using El34(more sweet); KT90 (Good bass an some sweetness)or 6550 (for the most bass punch). At least that was my eperience and I had one for over 4 years. If your starting out in tubes it gives you te option of tube rolling and you won't be dissapointed. I sold mines in 8/10 condition for just below $1,500(retails $3,400). Another option would be one of the 845 tube integrated manufactured by Unison Research. You may have to pay a little more for a used one, but they are very good amps despite not being as well know in the US.
Primaluna Dialogue Two; my 4th amp and I am now happy.

Good Luck-
I second the Cary SLI-80. It's a flexible amp in that you can use KT88's, 6550's, El34's, etc., plus is has triode and ultralinear modes that you can shift on the fly. Plus is has subwoofer outs that many amps are missing and it has a great headphone out as well. Used Sli-80's show up regularly in the classifieds within your budget. Although I have not had the good fortune to hear the Jadis Orchestra, I'm sure its a great choice as well. IMHO, few integrateds exude class like Jadis and I hope to own one one day.