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.

Forgot to say you should be ok as is in terms of gain. My Urushi Wajima  behaves as if it puts out more like 0.5-0.6mV.