Comparison of Audio Horizons Preamplifiers

I currently own a TP2.1 from Audio Horizons and thoroughly enjoy it. I wondered it anyone has had a chance to audition the new unit and been able to compare them. I am thinking about upgrading. Thanks in advance for all suggestions. Steve
the 2.2 is a bit sweeter thanks to some careful parts selection (hi fi fuse & furutech gold IEC), but the 2.1 is a bit more dynamic (thanks to 2 trannys).

i'd think upgrading tubes (1 & 3) or coupling caps would be the best thing you could do.
I am in process of upgrading my 2.0nB with all currently available upgrades except transformers and will let you know what I think of the difference. Have also thoroughly enjoyed my AH