Cartridge rings at certain high frequencies

Hi all, I am new to the forum, and this is my first post. First my system, mainly vinyl based and consists of Linn active Amps & Speakers, with a Michell Gyro modified with the Orb platter, plus an SME 309 arm. Phono pre amp is a Graham Slee reflex C, cables are Nordost. Cartridges are various, but exist on all of them, currently an AT33EV MC.
On certain high frequencies I get a ringing sound, a sort of harmonic, but not truly a harmonic sound. It's not on all albums I play, such as all my 180gm, but shows up on a lot of the 120-140 general vinyl. So far I have tried the following. Checked the arm and cart every setting at least fifty times, so much so I can now set the Azimuth blindfolded and asleep. I thought it was my music room, so in went the rugs, carpets, cushion, sound defuses, traps etc. didn't make any difference, it was still there. The TT does have DensoDamp fitted and the SME doesn't ring at all. The only thing that hasn't been changed is the cable......so I have bought a lot of Linn cable to try, but first thought some of you kind people may hopefully tell me of something that I have missed.
I do have a DS player, not that is used a lot as vinyl is my prime listening pleasure, and I occasionally get the slight ringing, but not as prevalent as with my vinyl setup. Thank for reading and thank you for any assistance that you can provide.
Brian in the UK