Audible Illusions modulus 3A, what would be the next level of up grade?

Backert Labs.

The Calypso was on my short list and there is one available locally.
It is highly regarded in the forums. I did have direct discussion with a couple of people that have owned one and they said they were a little noisy. Noise bugs me. I should still check it out.

I haven't listened to one in a long time, but my impression is that the 3A is very good. It may be hard to beat for near the same kind of money. It does have a ton of gain which isn't an issue for vinyl, but might make finding a good match amplifier wise more important than finding another preamp that is "better".

If used as a line stage

The best part of any Audible Illusions preamp is their phono section, especially the John Curl MC one.  I was upgrading to a better speaker long ago when I first bought the 2D.  After hearing what I could getting sound improvement from over doubling the cost of $900 speakers back in 1990, I kept hearing such a great difference in the sound with any of their speakers vs. my own setup.  I had a good PS Audio preamp with phono then and brought it back in to Quintessence Audio to listen to it vs. the AI 2D.  The AI just brought the music to life and was very organic and beautiful sounding with every record I played--so much so that I bought the 2D for $800 and had a very significant improvement to my system for a whole lot less than buying the better sounding speakers.   The 3A was just as impressive when I bought it later.