Lewm- where in the world did you get the idea that the PHT is magnetic? It is not, so therefore your question about increasing the magnetic field intensity is moot. No manufacturer that I know of would design and market an add on magnet for use with ALL types of cartridges- MM, MI, or MC. The PHT is a mechanical/acoustic transducer ( granted an extremely small MICRO transducer). I have used it with Lyra (MC), Ortofon (MC), Soundsmith (MI), and Benz (MC) cartridges and I can absolutely verify that it does make a discernable impact on the sound quality of the analog playback.
