I have been doing some research on the core materal used in the 5 coil VIC.
Ferrite 43 material which has a permeability of 850 (which I think is too low) and CN20 Ferrite which has a permeability of 925. Both of these materials are NiZn Ferrites which are typically used at frequencies above 500kHz.
There are also MnZn Ferrites, from what I have read these ferrites have permeabilities above 800 and are used at frequencies from 1kHz to 1MHz. So I'm thinking we need a MnZn Ferrite. Right now I'm looking trying to find an MnZn material which has a permeability around 1000. Core material selection is something I have very little experience in, but in Meyer's case I think it is very important to find the right material.
