Where would you go from VAC Avatar SE integrated ?

That's what I thought - stay with VAC. But maybe there is something out there that people here are aware of that could be interesting and worth considering. Perhaps something more rare or exotic.

Synthesis ? Italian, right ? Never had Italian equipment, by the way.

VAC produces great equipment. Then the VAC Sigma 170i IQ integrated amplifier sounds like a really good choice for you. 

I certainly wouldn't want to change the basic character of the sound. I would not call it lush really but it is quite warm, natural and inviting. What I might want to add to it could be more resolution, a bit more precision, high frequency extension and power. However, it is quite good as it is. I use 12AX7 Mullard long plates in preamp, 12AU7 RCA black plates in the driver slot and SED 'Winged' EL34 tubes. Same Mullards for the phono stage.

the avatar is a great integrated from a time when Vacs gear was much more affordable

one of our best integrated amplifiers is the synthesis a 100 it is a similar sound to the avatar via kt66 tubes under 12k vs 16k for the vac 170 it is also more powerful at 100 wats vs 85 andd has a great built in dac.

in addition to sounding great it has a fantastic built in Dac

the dac is based on their separate 3k dac

so all you need is a digital transport and a set of loudspeakers.

https://www.hifinews.com/content/synthesis-action-a100-titan-integrated-amplifier

Dave and Troy

Audio intellect NJ

Synthesis dealers.

I'd suggest one of the newer VAC integrateds, since you like the company sound.  They use KT88s, though, so it might not be quite as lush as the Avatar, as I recall its sound.  I'm not sure how you want to "better" the sound, though--do you want more high frequency extension, tighter, deeper bass, etc.?