KOETSU VERMILION and audio research PH7

I doubt it! Get a good mc transformer (SUT) to maximize the signal-to-noise range of the Koetsu - and your other mc"s.

I have a Bellari and a Quicksilver, plus two custom-built SUTs I prefer them over active stages!

The Urushi Vermillion spec is .4 mv so would work.  If .2 mv it would not.  I owned the PH-7 for years so the answer is easy - upgrade the phono pre instead.  I went Herron and it spanked the poor old PH-7 (NOS Telefunkens) without mercy.  

First, as wlutke says, the output is at least 0.4mV, unless the cartridge is in the Platinum series, which I doubt because I don’t think Koetsu made a Platinum version of the Urushi types. (Vermilion is essentially a red Urushi.) Second, it’s not a good idea to mate a SUT into an MC phono section even if the input resistance is 47K ohms, because you are very likely to overload the stage. If input R is the more typical 100 ohms or any value much less than 47K, that’s a much worse situation. Don’t do it.