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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
actusreus OP
733 posts
 
Dan_ed,
I'm genuinely interested in what those in the know, or more knowledgeable than me, have to say about these different approaches to phono stage design. But certainly I'm also hoping that the discussion would assist me with my selection. Auditioning in my system might be difficult.
dan_ed
2,451 posts
 
Well, good luck to you. Don't be surprised if it gets to be somewhat of a "religious" discussion. ;-)
atmasphere's avatar
atmasphere
11,901 posts
 
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).

actusreus OP
733 posts
 
Atmasphere,
Would it be correct to say all-tube phono preamps are rather rare?
atmasphere's avatar
atmasphere
11,901 posts
 
Hadn't really thought about that! We make two... it might be interesting to take a poll.
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