Excellent Transformers ??

I am looking for a excellent transformer, but with these units I have absolutely no experience.
Reason:
I am looking for a Atma-Sphere MP-1 MK II, this one has a build in phono section, which should be very good, from what I heard.
But I am using a Miyabi Cartridge, which has a output from .24mV/4 ohm.
I think that's absoulutely at the limit to work there.
Maybe good, maybe not.
I will see when I have the MP1.
But when there is someting to improve, I would like to know, in which direction I should look.
It is not urgent, because I have a Klyne 7 phono preamp but I never had a transformer and I am interested, what's going on with these.
Thanks