Anyone here using Bent Audio MU MC into Modulus 3a

yes, that's it.

I used the AI M3A with the built in Gold MC phono board for about 5 years. I thought it was quite good at the time. I then moved to an integrated amp and purchased the K & K Audio phono stage. Without question, this phono stage is a big step up from the phono stage built into the AI (before you ask, yes I did do substantial comparisons of the two). I then got a chance to hear the Mu Mc through my K & K and it was a significant, further improvement over the Lundahls built into the K & K. I bought a used the Mu Mc to used with my K & K. All this to say, the Mu Mc is the best step-up I have heard in my system and I cannot imagine that you would not be happy with it. However, I think you need to question if it is really worth spending a substantial amount of money for an improvement in the phono section of the AI. The AI is already quite limited and you would probably be better off spending that extra money on moving to a different preamp altogether. Just my opinion, of course.

The K & K phono stage only comes in one standard version, although Kevin Karter can customize the disign to some extent. This phono stage has both mm and mc capability and it also provides 3 or 4 load settings for mc cartridges. It cost about $1,700 new. This would be, in my humble opinion, a better purchase than the TX103 as it would give you superior phono with both mm and mc cartridges. There are other good phono stages on the used market that could be considered (eg. Audio Research PH3SE, Herron etc.).

No! The latest I heard was made 1999. I believe there have been improvements since then but I do not know how extensive they are or the improvements they make.