Sound of transformers in preamps?

Rsimms, yes, single-ended tube circuits are known for 2nd ordered harmonic distortion, which gives them a lusher sound. This is the same effect a transformer can impart. Although it is pleasantly euphonic, the distortion does impair transparency/detail.

Philipwu, generally speaking resistors are more stable with respect to frequency! I'm pretty sure the reason transformers are turning up in preamps is just above in this post.

Yep, it's a fetish. If you want colorama maximus, loss of transparency and destruction of musical timing and loss of coherency then by all means buy more stuff with transformers in it.
Transformers = hysteresis distortion, bandwidth limitations, phase shifts that differ at different frequencies, even order distortion ( in single ended applications ).
This article gives you a good insight -
http://www.jensen-transformers.com/an/Audio%20Transformers%20Chapter.pdf

Well, don't forget: High End
That means, when 20 normally cry loud "NO, that is wrong",
then it is normally the way to go for a Designer who has a better brain.
The customer simply has to find him. But that needs brain, too.... :-)

Dover, thanks for the link to the transformer information. That was very informative. It is probably a little like finding out how sausages are made though. One part of the picture lost is the problems created if you don’t use transformers. The alternatives have a lot of issues and problems too. One time at NASA I tried to find a linear capacitor. That was hard to find. I would think that isolation would be a very significant advantage of transformers, especially in a preamp.

Bob

Rsimms, isolation is only a problem if you have a severe ground loop or problem with AC power where you are trying to run the system where part of it is on one line and another part on another line.

However an interstage transformer will not help you with any of that.