Sorry for jumping into the discussion, the main subject was never clear to me, even after reading many posts and detailed explanation on vinylengine article for example.
I have Fidelity Research AGT-5X SUT, which can accept loading of the carts from 3 to 10 ohms, with respective gain from 31 to 29 db. If I look at the carts produced at the time SUT was made, carts by FR, they all fall into 3 to 10 ohms load impedance (with 2 carts as exception), which would make a lot of sense to me - mfrg making SUT to fit their carts, why would they make incompatible SUT at all (I presume that they making SUT primarly for their carts, not just for the market).
Now I have Transfiguration Phoenix, which has impedance of 7 ohms, and requires loading higher than 7 ohms. That should almost perfect match between SUT and cart.
But I am reading not for the first time about 3X or 10X rule of thumb ratio between cart impedance and SUT loading, which makes me confused again.
My Phono stage is Audion Phono (which requires impedance of 47 kOhm which SUT has), volume of playing at the same level as say from CD, not different.
Can someone clarify?