Advice on integrated tube amps

I assume you meant under 1000. I would look for something in the Jolida line. The only problem I know of is they have customer service issues from time to time. If you could go above your budget you might look at the Rogue Mag. Tempest. You can find them for about $1500 used.

Bill Baker of Response Audio is running a clearance on Ming Da amps and had two MC-88 units left a few days ago. It has a true active tube preamp stage unlike most of the so-called tube integrateds. I'd have bought one myself but I have no need...

cayin ta-30 from bizzybee or primaluna from upscale audio

To better understand and assist: What amp/pre are you currently using? What do you like/dislike about it? Have you demoed a tube amp in your system? Why do you think tubes may be a good choice?

If your Audience 50s are 4ohm, 88dB you may be happiest with a late-model, higher quality used (say, Audiomat Arpege) tube integrated for $1,000 - $1,500 that can drive and control your speakers. If you don't require higher listening levels on dynamic music, there are several
quality(?) Chinese tube integrateds out there for $1,000 to $1,500 (new). Just know that some are unsupported and the longevity may be questionable.