Preamp 47K load. Cartridge needs 330 ohm

The loading is not the main issue.  The PV7 has a phono input designed for MM cartridges.  It is expecting an input voltage of 2.5mV to 5mV.  Your MC cartridge only has an output of 0.35mV.  You need a phono Step Up Transformer (SUT) that provides the required increase in amplification voltage and will also address the loading issue by its presence.  You will need to do some research but a 1:10 (20db) step up would also give you a loading of 470ohms if my memory is correct.  That would be adequate to get started.  Another option is an active phono head amp  that does not have the RIAA curve in its amplification because going into the PV7 MM phono input the signal will pass through the RIAA equalization within the Conrad Johnson (don't want to do that twice). Last option is a total external phono preamp capable of handling the MC amplification and loading that would plug into an auxiliary input on the PV7.

A 1:10 SUT is perfect for your needs. And no cartridge has an absolute requirement for a single particular load resistance. A 1:10 SUT will result in a 470 ohm load and that is just fine for your cartridge. See above for other viable solutions.

your cartridge is 0.35 signal strength; it's coil impedance is 2.5 ohms

the answer:

Exactly as said above: Step Up Transformer with a (+/-) 1:10, ratio (which is it's xFactor),

Like lewm said: result of 1:10 x factor will change your cartridges 2.5 coil impedance to 470 which will be 'shown' to your PV7 MM Phono input'.

.......................................

the math:

your .35 cartridge strength will be  Stepped Up (multiplied .35 x 10 and be increased to 3.5V, a perfect strength for your PV7 MM Phono Input.

Impedance load is a 'guideline', kind of a minimum that the cartridge wants to be 'shown to PV7'.

.....................................

Choosing a SUT, the indicators on the front often do NOT tell you the xFactor, you need to find out/ask which SUT has a transformer inside which can do a (+/-) 1:10 xFactor. 

i.e. my SUT, Fidelity Research FRT-4 (I had to find the specs) has optional indications on the face, the face option of 100 ohm results in an xFactor of 10.55. which results in 423 ohms 'shown' to your PV7 for your cartridge.

........................................

I put copies of the research I did about SUTs as one of my Virtual Systems.

Click on my name, choose 'details', it will take you to a page with a list of Virtual Systems, one is named 'SUT info'. One column shows the xFactors.

Small print of scanned pages: temporarily change your monitor' ZOOM from 100% to 150%s. Put back to where it was, i.e. 100%.