Sudden cart/arm compliance issue?

Hi,

I have a Rega RP3 turntable with stock arm, and an Audio Technica AT33ev cart. Up until the last day or two, things have been fine.

Now, on records that may have some imperfections toward the outer edge, I am getting low level intermittent rumbles I have never heard before. Of course, once we get to the middle of the record, it is mostly if not entirely gone.

Sounds to me like a compliance issue, but it came up suddenly. The cantilever on this cart has a lot of give in it, it seems, but, like I said, never had the issue til recently.

Is it heard of for a cart suspension to 'settle in' and loosen up, causing compliance issues that may not have been experienced at first?

 

And, no, my phono stage does not have a subsonic filter. So I don't have that option. But, as stated, never needed it before, and that doesn't seem like an optimal solution.

 

More info... when I watch the cartridge during these episodes, the stylus seems to be jumping in and out of the groove ever so slightly. It isn't much to see, but it is moving. Not staying firmly put in place.

This has never happened before. I double checked all aligment and tracking force, and it still bounces.

So, I am right to think I am probably looking at a failing suspension?

 

Perhaps I just have a mismatched arm/cart. There is another variable in place. A new set of headphones I am listening through. It may be very, very possible this problem has been there all along, it was just masked by my other phones which may have rolled off much sooner than these.

But, I recall reading somewhere that the AT cart and the Rega medium mass arm worked fine together. Maybe not.

Sounds like I need to invoke the warranty. Hope it has a good one.

 

List your other components, what geometry and VTF are you are using on your cartridge? How old is your stylus?

 

Rega RP3

Audio-Tech AT33ev MC cart

Loefgren B, pivot to spindle set at 221.7

VTF 2.0 gram

Cart and Stylus 6 months old, not much actual use

Meticulously set to Lof. B with arc protractor.

This is a new phenomenon, I double checked all my alignments and they are still spot on. 90 percent of it occurs in outer grooves at the beginning of each side.
Never heard anything like it before. My tracking has always been exceptional with this cart and arm, with VTF set right in the middle of manufacture recommendation.

Audioquest cables, if that matters, and

the weak link in the system, the entry level Music Hall PA-1.2

I wish it had a subsonic filter to help with this.

On a perfectly flat record, no issues at all. But any slight warp-age at all, and it is successive low frequency 'taps', and like I mentioned, I can see in those places some cantilever/stylus flexing.

For instance, I first heard it tonight on the first track of my 'Pretzel Logic'' LP. It was very, very bad. I have played this LP several times before, and nothing like this has ever been present before. And it extends to any LP that is even just slightly less than perfect. And it once did, and SHOULD track those LP's just fine.

The AT33ev is a low rider, and seems to have a lot of give in the cantilever. I am thinking that the suspension has 'loosened up' over time, and I have developed a compliance issue

 

Then again, this could have always been there, just, not exposed by my older set of phones, that didn't seem to have near as much deep bass response. Like a subsonic filter, but not Perhaps, and perhaps this is the way I am leaning, there has always been a bit of compliance problems, I just really couldn't hear the effects nearly as well previously.

Like for instance, the bass line in Miles Davis' 'So What' That bass line was barely there on my Grado headphones. It is very, very strong and present on my new set of Sennheiser HD650. Seems to reason that a major increase in bass response would mean near sub-sonic rumble artifacts would be much more audible that before.

 

Nothing immediately jumps to mind. "Taps" is the cart body contacting the record? Do you have another cart to swap for a test? Failure of the suspension is a possibility as you surmise. Luckily there are quite a few knowledgeable folks here on the forums so be patient and check back. Some one might know what's going on and more importantly have answers.