Budget Tube Preamp ($2000)

Hello guys,
First post here!

I am in the market for a tube preamplifier for my current system, to add a bit of warmth. My budget is under $2000, the cheaper the better, Mainly looking at the used market (I love great deals). 
My build currently:
- Monitor Audio Silver 300 speakers
- Project Debut Carbon Turntable
- Marantz Cd5005 CD player
- Cambridge Audio Azur 851N
- Rotel RB 1582 Mkii Power Amp

If you guys have suggestions, I appreciate it a lot! For the inputs, if the preamp has XLR that would be great as I'm currently running my Azur 851N to my amp through a balanced connection and it sounds pretty good. This is not completely necessary though. 

Thanks!