I recently installed an Audio Technica VM540ML on my friend’s Empire turntable, which has a Grace 700 tone arm. Install went smoothly, anti-skating and tracking force are good. Everything sounds great, but he’s noticed an odd problem. On certain pressings the setup seems very sensitive to record warp at the outer edge of an LP. If I shine a bright light and look closely I can see that on each revolution the cartridge jumps up and down slightly and briefly. We hear a little distortion (in the left channel only) and of course a slight thump. This happened on 2 out of 10 records that we tried. It only lasts for about the first 30 seconds of the track. I took two of the “problem” records back to my place and played them on my SL-1200, which has a Share V15 (with a brush in front of it) and a different model Grace arm. Not only was there no thump or distortion, I couldn’t even see the cartridge lift up at all in the places where it did on his TT. It was as if I was playing a totally different pressing. Amazing to me. I discussed this with by buddy Kevin Gray, and he thought it might be a tonearm resonance issue. I am also wondering if this might be a downside of the AT cartridge having better LF response. I mean, clearly there is a warp in the record, which should be passed on the speaker cones, at least to some extent. Maybe it has to do with the cart’s compliance? I don’t think there are any flaws on his turntable platter that could cause this. And I wonder if the brush on my cartridge helps it "ride" the warps somehow. I should mention that his Grace arm has had some kind of makeshift repair near the base, and may have some kind of mechanical issue. Not sure what to make of this. Has anyone else run into this? Any thoughts? It’s not a huge problem but maybe it can be improved in some way. Thanks in advance.