Distortion mystery -- MC cart mistracking? / transformer / head amp input saturation??

@sfall  I totally get it that carts change a lot with break in... but this distortion sounds like mistracking or some kind of input overload.... not sure a less-than-broken-in cart would sound this way.... or am I wrong about that?

to dover and almarg

yes you are both quite right... thank you

almarg - my unit is a ANS2 ’H’, thank you so much for your calculations

i had been using the L setting of the ANS2, which in fact provides slightly more gain than the H setting (counter-intuitive, but I am now clear on this) ... my error -- in due course i will try the H setting on the transformer -- the internal impedance of the R100H is somewhere in the middle of the two impedance ranges quoted for the ANS2 settings... I should indeed run the other and see if it cures the ill...

by the stated ANS2 specs the gain is only +/- 2 db in the 2 settings, so not much, on paper at least, but almarg your calcs make it more obvious that into 47k ohms the gain differential is much greater... thus most likely the root cause of my problem - THANK YOU :)

sidebar -- that Mockingbird/Jasmine 2.5 unit is very very nice... punchy, quiet, big stage... plenty of gain of LOMC... incredible value for an active head amp, very glad I tried it after reading A Salvatore’s notes on it...

Further on this... I have discovered the Zyx cartridges' output is measured at 3.54 cm and the ART 9 output is measured at 5 cm... so measurement standards are in fact quite different.  

So taken at face value, the R100H output is 41% higher than the ART 9, or measured at the higher standard, R100H output is at least 0.68 mv (vs the ART 9 spec'd at 0.5 mv)!

That would explain some input overload at the head amp!!

no i am now determining that it isn’t electrically overloading

the cartridge distorts at the same points on the same records using all step-up and amplification methods

the zyx is definitely not tracking properly or is somehow damaged

i have used the same vpi arm jig set up procedure for ART 9, Koetsu and Zu Denon 103 - the other carts don’t distort

Zyx being sent to Soundsmith for evaluation...

Peter Ledermann at Soundsmith called me upon receiving my Zyx, and he said the cartridge looks fine... minimal wear on the stylus, stylus is clean, suspension looks fine. He then asked about my setup. When I said I was not using the VPI JMW arm anti-skate gizmo, he emphatically said that was the problem causing the distortion. He said some carts like the Zyx (and his own SS carts too, evidently) really need anti-skate to track properly... and to read and carefully follow his very lengthy and specific instructions on his website regarding setting AS in general, and setting AS specifically for the VPI unipivot arms. So he is sending the Zyx back to me.

In the meantime I have spent a lot of time last couple days learning/reading and setting up AS on the table/arm ... of course Peter’s view on AS is diametrically opposed to Harry W’s. I have read a ton about this now on the various boards and there are clearly 2 fervent camps, Peter’s says gotta have it, Harry’s says no need, basically. Anyhow, following Peter’s instructions leads one to dial in A LOT of AS into the JMW arm. A LOT! I had to buy several metal washers to mount on the AS lever arm to slow the tonearm from skating inside hard, then the AS nylon string pulled so hard on the unipivot that it tilted the arm, causing an azimuth issue. So then, readjust the eccentric counterweight to offset the skewed azimuth caused by the anti skate. Jesus.

Alas, all is dialed in - at this point not using the Zyx yet as it is still in transit back from Soundsmith. But with my Koetsu and ART9, with the AS dialed in ’properly’ per Peter L, I would say things sound great. But then again, with these two carts, things sounded great before too, as these were problem free carts, unlike the Zyx which distorts. Will need to listen more and more critically to see if I prefer which camp of AS.

Zyx will be back in a few days... will try it with the AS dialed in. Hopefully it makes a difference.