Several audiophiles on this " SUT's party " have any idea what I'm talking about when theyare so happy with those SUT they own that does not permits that the cartridge can shows at its best.
That's correct.
MC Step Up transformers are like candy - what flavour do you prefer.
They are not linear.
They have phase shifts.
The variations with different cartridges goes well beyond loading (input impedance) and gain.
If you talk to cartridge designers like JCarr you will find that different core structures as well as materials mate better with some MC's and not others, even if they have the same internal impedance and output. For example - with some cartridges a toroidal MC Step Up may be preferable due to the design of the MC.
For the end user they are a crap shoot. For every cartridge you buy you would need to buy dozens of transformers to trial and find the best.
Price is no indicator and "specs" are not always an indicator as to which is best.
But at the end of the day you can't avoid the shortfalls - distortion, phase shifts.
As I said above MC Step Ups are candy, they provide a rose tinted view of the world. I have a draw full of some of the most highly regarded MC Step Up's - I don't use any.
In the vintage years Tamura and Altec were the best transformers as a line models. Some of them silver wired.
And there are a few others. I have some vintage Altec's from the 50's that have individually annealed layers within the core - that is each layer of the laminated core has a specific annealing process that is different for each layer. Those Altec transformers also have teflon inserted between the windings. There are no transformers today that approach the level of intricacy within these vintage transformers were built and wound. Altec for example I believe had some 200 staff working specifically on transformer R&D, development and testing in the early years. No manufacturer could carry that cost today.
