Cartridge distorting progressively during playback


Has anyone experienced this in their setup.  Record plays fine at beginning but begins to distort ( especially in midrange).  Here is the hitch.  It plays fine if you start with the first song middle or last.  But after a while the distortion progresses.
If you lift the tonearm and wait around 30 sec or more and lower to play the distortion disappears but will return in the next few mins.  It will do this if you re cue the same track or one near the beginning or end.

I have tried two phono stages and it does the same with both.  I tried a different cart (MC) and it does not do this.  

The cart in question is an Ortofon 2mBlack that is brand new.  It was set up the same as the previous 2mBlack it replaced under warranty (cartridge pin came off). SRA at 92, 1.5g tracking force.   Tracks perfectly.

Any insights on what is going on.  I figured I'd get some input before I take this back to the dealer.  Maybe there's something I overlooked. 
nutella

Showing 2 responses by pops

Couple of questions - does it distort in both channels or only one?

Did you set up the cartridge?  Have you rechecked all the setup parameters?
@nutella it sounds like a defective cartridge to me - unlucky! I have a similar situation with my Transfiguration Proteus except my problems started after 500 or so hours - you can check the thread  "cartridge issues."

Like you I am pretty savvy with setup and tried everything - several times. What tonearm are you using? noromance has a good suggestion.