Need help with diy ribbon mic

[mbf90]

Hi,

I decided to assemble my own ribbon mic by purcahsing Artur Fisher’s ribbon motor from diy components, an Ami TR42 transformer, and an old Japanese dynamic mic that copied the rca 77 in body style to use for the body.

However, some of the parts of the body are magnetic. I was able to make some brass rods inside the mic to support the ribbon motor and get rid of the magnetic steel rods that were inside.

My current issue is the grill of the mic, which looks just like an rca 77, is also magnetic. It is not as magnetic as the metal rods that I took out and I am wondering if it will be ok to use or will it disturb the magnetic field of the motor and degrade its performance?

Thanks,

Matt Fishel

 

[Khron]

Are magnetic fields subject to the inverse-square law?

<edit> It seems they are indeed - https://en.wikipedia.org/wiki/Inverse-square_law#Formula

Either way, i would think that by sheer virtue of the grill being dozens(?) of times further away from the magnets than the ribbon itself is, if it actually had any measurable(?) effect on the magnetic field, it would be purely academic / imperceptible.

In other words, i wouldn't worry about it. In fact, i quite wonder what the grills of potentially famous / classic ribbon mics are made out of (perhaps apart from Royers though).