Active FETs vs. Step-up phono stage designs


I've noticed quite a few threads on A-gon discussing step-up transformers recently, and it got me thinking of the different applications in the phono stage design. I'm curious of the advantages and disadvantages of designs that employ step-up transformers vs. active designs with FETs, especially in tube preamps. Examples would be the new Manley Chinook vs. the Rogue Audio Ares with its custom Cinemag transformers, or the highly-regarded Andros, which also went the step-up route. I'm thinking of upgrading my solid stage phono preamp in the near future, and would like to hear your opinions (and I know we have a few designers posting regularly) regarding this subject.

actusreus
Well, good luck to you. Don't be surprised if it gets to be somewhat of a "religious" discussion. ;-)
Dan_ed got that right...

Its been my experience that you don't want semiconductors at the input of a phono stage- they just don't have the same low level detail as an all-tube phono section.

I don't like transformers for the same reason- they limit bandwidth and loose detail.

But noise is also an issue. If I had to compromise (meaning that I can't use a phono section that is all-tube, is quiet enough yet has the needed gain), I think I would go with an SUT before using semiconductors. I guess I don't like the semiconductor sound (brighter due to emphasis of odd ordered harmonic distortion, lacking in tubes and SUTs).

Hadn't really thought about that! We make two... it might be interesting to take a poll.
Aesthetix is all tube gain stages I believe. I believe they are all tube gain stages. I do think the mm with SUT is perhaps the "standard". However, there can be more work involved with getting SUT loading optimized. Not a big thing, just a bit more work involved.

In my case, the phono stage I use has a FET mc gain stage that is configured conservatively. I.e., most of the gain is realized through the MM stage. I can run my XV-1s through my MM stage. Obviously, it sounds much better through the mc inputs, but I think that gives an idea of how much gain is applied at each stage.

I leave the discussion now since Actusreus is really looking for designer input.