What does the app actually detect, EMI or "magnetic fields"? Those are two different phenomena. I would expect it detects EMI. I don't think this is endemic to every single DD turntable ever made; I would expect it is something to think about on a case by case basis with any particular DD. However, as Banquo mentioned, the L07D cognoscenti recommend implementing a shield between its motor and the platter. It seems to me that Kenwood already did that: the platter "mat" is actually a 5-lb piece of quarter-inch-thick stainless steel, which while not being a perfectly efficient shield, does act as a shield. Nevertheless, I did buy a piece of TI Shield from M Percy. I cut it in the shape of an LP and tucked it in under the stainless steel platter mat, so it does not show. I then was able to imagine that it made an improvement; I don't trust such uncontrolled observations when made by the guy who did the work and spent the money (me), but there you have it. One could do the same or similar for the TT101 or any other DD. A copper platter mat would do some good as an alternative. The SP10 Mk3 has a massive piece of bronze or brass in its surface, which probably affords some shielding. Unfortunately, last time I looked on M Percy's website, there is a notation to the effect that TI Shield is No Longer Available. I don't know whether that means it is out of production or only no longer sold by Percy. He does also sell ERS cloth, which could be made to do the job.
Note that any shield must be grounded to be fully effective. I am assuming that, since the TI Shield on my L07D is fully in contact with both the base platter and the SS mat, and since they are in continuity with the bearing, my shield is grounded. (TI Shield has layers of copper on both sides; it is quite conductive. Be careful.)
