Hum Issues - Rega P-25 w/ Grado Reference Platnum

Here's more info on one solution that was recommended above:

Well, here is one from the archive : (for Rega 2/3, from an article in Audio 1998 by Cory Greenberg)

The material used comes from Magnetic Shield Corporation and is called Mu-Metal. There is a lab kit that contains several sheets for $80, CO-NETIC AA for low intensity fields and NETIC for high intensity fields.

Shielding the motor with the NETIC didn't work so he tried placing the CO-NETIC sheets on the base under the platter, and this did it.

He recommends is to remove the cart from the arm and the glass outer platter and plastic inner spindle from the turntable. Be careful when cutting the hole for the bearing, because the sheets can bend and may scrape the underside of the plastic inner spindle. Fix it with double-sided tape. If you don't like the color, you an paint it without changing it's shielding properties.

One can buy directly from the company 630/766-7800; ask for product LK-110.

This was pulled from an AA archive.

Here's a link for their site:

Mu Shield

Hello,

Your problem is normal with your grado cartridge because it is not protected against the magnetic and electric fields from the motor. You have two solutions. First, put a metal cover under the turntable between the motor and the plinth. Finnally, change your cartridge and choose one which is well protected against the magnetic and electric fields. An example, the rega Elys or the old Linn K9.

Hey Tom- Where is ya? :~)
Hum? Nah!