the debate is over, @atmasphere, he verdict has been in a long time"you get the best MC sound quality with a properly matched and loaded SUT into a MM phono.t case closed.
@cey This statement is false, based on a logical fallacy of limited sample size.
You cannot get the bandwidth of direct-in from the best SUTs available. SUTs also have distortion due to the sigmoid curve that is a function of all transformers. Case closed on that.
This isn't saying that all SUT setups are inferior to all phono sections that can operate direct-in. But the two parameters I listed are very real. However the question really is: is it worth it going direct in since the extra gain needed will result in more distortion?
A way around that of course is to run the direct-in circuit fully differential. Not only will it be lower distortion; it will also be lower noise. When comparing side by side with the correct loading for the SUT, the direct-in has always been more transparent (BTW the best way to know that is to have access to the master tape; I've been doing recordings and mastering LPs so this is not a challenge).
We spec our phono section to 100KHz on the RIAA de-emphasis curve. Most SUTs are incapable of that sort of response. Yet we don't have issues with RFI and if a different cartridge is used, its plug and play. No having to sort out what the correct loading is (which, if an SUT is used, will be different from cartridge to cartridge).
The debate is far from over; its not really a debate anyway, since it won by what works the best as opposed to wordplay.