Is there a problem with my Lyra Delos cartridge?


Last March I upgraded from a Grado Platinum to a Lyra Delos cartridge which was installed by Analogique in Manhattan.My turntable is a VPI HW-19 MK-3 with an Audioquest PT-6 tonearm.After about 120 hours of use I have been getting distortion on certain lps.For example:Last night I wanted to hear Moment's Notice from Coltrane's Blue Train lp(180 gram).This is the second track on side one.So I drop the needle on track two and sound starts distorting at about the 7 minute mark(track is 9:09 minutes),I lift up the needle then lower it onto the lp again and it plays fine.This is not happening on every lp but it is happening quite often.I am tracking at 1.8 which is the Lyra recommendation.I switched phonostages but that does not seem to be the problem.I also put on a new belt but problem persists. Help!!!
montgomery
Just a thought - does this happen with only 180g or other weights too? Do you adjust VTA for thicker discs?

You mentioned that you're on the upper limit of VTF for the Delos. Sometimes we can exceed that if VTA is unfavourable? I've certainly exceeded the max on some carts by up to 0.1g (I know a lot of people go even higher than this on some carts) and always wondered if sustained use at heavier forces can distort the suspension permanently, especially in warmer climate, or the User can just cheerfully regress back to lighter VTF after 200 hrs or so...(?)
Thanks for your response Moonglum.The distortion has occurred on a variety of lps.I have to make a decision on taking this to Analogique for service or upgrading to the VPI Classic One and the much better JMW tonearm.Thanks again.
As others have mentioned, 1.8g is on the very top end of the recommended VTF range. And VTF on these is pretty particular, like a couple hundredths of a gram making an audible difference.

I'd slack it off to 1.7g and work towards the recommended 1.75g. Mine was happiest at 1.735g on the VPI 10.5i arm, and I can heartily recommend that combo if you decide to go that way. But I'd take a little VTF off it first.
Montgomery,

I would say you should check the stylus raking angle (SRA). I was getting distortion from my LP and I experimented with the SRA and solve the problem. In some your tracking force could also be the problem, as other have pointed out. To little tracking force will cause the tone arm to jump around. So check that first then the SRA.
I moved the tracking force up from 1.6 to 1.8 thinking this might be the problem. No problems ever with tonearm jumping around.I am not very good at tweaking things myself.Is there a easy way to check SRA? Last year at this time I took the turntable into the shop to have what turned out to be a short in the interconnect wires fixed and believe me the repairs were not cheap. So I have had problems in the past with this turntable and do not want to spend anymore money having it fixed and that is why I am thinking about moving up to the VPI Classic One. Thanks