Warm, rich, smooth, 3d tube integrated amp, budget $6000

Thanks guys for the further thoughts. I agree with @pani it seems like those options are not rich, warm, full (based on my reading and talking to some friends).

Another name that keeps popping up for the sound I am looking for is Cary (SLI80) and Jadis (orchestra).

@audioman58 thx but not interested in solid state.

I haven't tried many alternatives but can say that the primaluna Evo 400 I own is a great integrated amplifier that doesn't run the tubes hard and is made to last.

Plenty of good reviews around.

The only downside is that the 8 power tubes are costly when replacing...cos there's 8. To my ears the kt150's sound better than the el34's it came with driving IMF RSPM IV transmission lines.

we are a dealer we sell a number of warm and powerful integrated amps being discussed here 

we sell the coda csib

the synthesis a100T

unison research unico 150 which is a hybrid

the synthesis is amazing the unico is also impressive

Dave and Troy

Audio intellect NJ

dealer Coda, Synthesis, and unison research

I own the Yamaha NS 5000 (no opinion on Vienna Acoustics or ATC) and it is well matched with Magnum Dynalab Integrated MD 307 and 309 (I own the less expensive 307). Both within your budget but midrange is not forward. The soundstage is deep, wide, clearly spaced instruments and vocals and natural sounding. Another outstanding option for the NS 5000 but above your budget will be the Ypsilon Phaethon. Used will be about 10-12K. Others spoke of Octave and I will also recommend. The Octave 500SE preamplifier with their MRE 130 tube mono combination will meet the asking requirements. All 3 Octave components are slightly higher than your budget and difficult to find in the used market but worth exploring. Good luck. No affiliation with any of these brands, except as customer.

https://octave.de/en/htdocs/verstaerker/mre130.php

https://octave.de/en/htdocs/verstaerker/hp500se.php

Rich? Forward mids? 3D sounding?

You've just described my Evo 400.

Others have mentioned better equipment...I would love a Luxman!

But if that's what you want, you could do worse than Primaluna.

Despite what you may have heard, the Evo line is a noticable step up from the Dialogue line.